Service

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Caddy 1996 , Polo Classic 1996 ➤

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Diesel injection and glow plug system

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Edition 11.1995

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Service Department. Technical Information

 Service
List of Workshop Manual Repair GroupsList of Workshop Manual
Repair GroupsList of Workshop Manual Repair Groups
Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system

AG. Volkswagen AG d
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Repair Group th eo
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01 - Self diagnosis

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23 - Mixture preparation, Injection

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28 - Glow plug system

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Technical information should always be available to the foremen and mechanics, because their careful
and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In
addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course,
be observed.

All rights reserved.

No reproduction without prior agreement from publisher.

Copyright © 2011 Volkswagen AG, Wolfsburg 00056406420

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

Contents

01 - Self diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . .n.A.G..V.ol.ks.w.ag.e.n A. . . . . . . . . . . . . . . . . . .1

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1 Self diagnosis . . . . . . . . . . . . . . . . . . . .y .Vo. lk. s.w. . . . . . . . . . . . . . . . . .es. n. o.t g. . . . . . . . . . . . . . .1
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1.1 Self diagnosis . . . . . . . . . . . . . . . . r.is.ed. . . . . . . . . . . . . . . . . . . . . . . . . . . . .ar.a.nt. . . . . . . . . . .1
o e
1.2 Function . . . . . . . . . . . . . . . . . .au.th. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e.o.r a. . . . . . . .1
1.3 Technical data of self diagnosis s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .c . . . . . . .1
s

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1.4 Connecting fault reader V.A.G 1551 and selecting engine electronics control unit . . . . . . . .2

nl

pt
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1.5 Interrogating fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

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1.6 Fault table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

ility
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1.7 Erasing fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

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1.8 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

h re
hole

1.9 Reading measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

spec
es, in part or in w

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23 - Mixture preparation, Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1 Servicing fuel injection system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

rrectness of i
1.1 Servicing fuel injection system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.2 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
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1.3 Rules for cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

1.4 Fitting locations overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

nform
ercia

1.5 Servicing injection pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

m

1.6 Servicing fuel filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

at
om

io
1.7 Checking fuel system for leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

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1.8 Removing and installing injection pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

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ate

1.9 Checking and adjusting injection pump timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

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1.10 Checking and adjusting idling speed, idling speed boost and governed speed . . . . . . . . . .30
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1.11 Idling speed boost actuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32op
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1.12 Checking commencement of injection valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
. C rig
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1.13 Checking engine temperature sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
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1.14 Resistance figures for engine temperature sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
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1.15 Checking idling speed boost valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
1.16 Checking full throttle stop valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
1.17 Residual volume basic setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
1.18 Removing and installing injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
1.19 Servicing injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
1.20 Checking injector nozzle valve tip for damage, injection pressure and for leakage. . . . . . .38

28 - Glow plug system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

1 Checking glow plug system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
1.1 Checking glow plug system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
1.2 Checking glow plug current consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
1.3 Checking glow plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
1.4 Glow plugs with burned electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Contents i
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
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ii Contents
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

01 - Self diagnosis

1 - Self diagnosis
1.1 - Self diagnosis

1.2 - Function

The control unit (J179) for the automatic glow period is equipped with a fault memory.

If faults occur in the sensors and components being monitored, they will be stored in the fault memory together
with an indication of the type of fault.

The faults stored can be read-out with the fault reader V.A.G 1551 or the vehicle system tester V.A.G 1552 =>
Page 3 .

The fault memory must be erased after the faults has been eliminated => Page 3 .

Faults which can be attributed to a temporary open circuit in the wiring or a loose contact, will also be stored.
These faults will be displayed as sporadic faults "SP".

An electrical fault in the glow plug circuit is indicated during the extended glow period (approx. 3 minutes) by
the glow period warning lamp flashing.
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General information au
ss for self-diagnosis is in the fault reader V.A.G 1551 and the vehicle system tester V.A.G
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1552 instruction manuals.
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1.3 - Technical data of self diagnosis

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◆ The data transfer between control unit and fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 is
carried out in the operating mode "Rapid data transfer".
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◆ The fault memory is equipped with a non-volatile memory.

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Selectable functions
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Function Ignition switched Engine idling

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02 Interrogate fault x x
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03 Final control di‐ x x

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05 Erase fault mem‐ x x

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06 End output x x
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08 Read measured Prote
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1.1 - Self diagnosis 1

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.4 - Connecting fault reader V.A.G 1551 and selecting engine electronics control unit

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

Note:
The vehicle system tester V.A.G 1552 can be used instead of the fault reader V.A.G 1551, however a print-out
is not possible.
Test conditions

• Battery voltage OK.

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• Fuse 21 OK.
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• Earth connections on engine and gearbox OK.

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Work sequence
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- -> Fold driver's side stowage compartment down.

- Connect fault reader V.A.G 1551 with cable V.A.G 1551/3.
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-> Appears on display:

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V.A.G - SELF DIAGNOSIS HELP

1 - Rapid data transmission*
2 - Flash code output*
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* Appears alternately
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If the display remains blank:

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=> Fault reader operating instructions

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After the fault reader has been connected:
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- Depending upon desired function:
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Switch ignition on
or
Start engine => Page 1 , Table "Selectable functions".
- Operate fault reader taking into account the information on the display:
- Press key 1 for "Rapid data transfer".
- Press keys 4 and 1 for address word "Diesel pump electronics" and confirm entry with Q key.

-> The fault reader V.A.G 1551 display will show the control unit identification, e.g.:
028906124B Saugdiesel V02
Coding 00124 WSC0000

2 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
◆ 028906124 = Part No. of the control unit (for up-to-date control unit versions see parts catalogue)
◆ Saugdiesel (naturally aspirated diesel) = engine version
◆ V01 = Control unit software version
◆ Coding: 127 without air conditioner, 124 with air conditioner
◆ WSC...Dealership number of the V.A.G dealer

- Press the ⇒key.

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-> Indicated on display: olksw not
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Rapid data transfer rise HELP nte
Select function XX tho eo
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- Further measures see repair procedures.

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1.5 - Interrogating fault memory

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Special tools, testers and auxiliary items

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◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

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Note:
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The vehicle system tester V.A.G 1552 can be used instead of the fault reader V.A.G 1551, however a print-out
is not possible.

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Work sequence

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- Connect fault reader V.A.G 1551 (V.A.G 1552) and with the "Address word" 41 select the Diesel pump
o

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electronics control unit. When doing this the engine should be idling.
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(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
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Only when engine does not start:
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- Switch ignition on.
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- Switch on fault reader printer with the print key. The warning lamp in key must light up.

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Operate fault reader taking into account the information on the display:
- Press keys 0 and 2 for function "Interrogate fault memory" and confirm entry with Q key.

-> The number of faults stored or "No fault recognised!" will be shown on the display.
X Faults recognised!

If one or more faults are stored:

The stored faults will be displayed and printed out one after the other.

-> After the stored faults have been printed out, the display will show:
Rapid data transfer HELP
Select function XX

- Eliminate the printed out faults using the appropriate fault table.
=> Page 4 .
- Afterwards erase fault memory => Page 6

1.4 - Connecting fault reader V.A.G 1551 and selecting engine electronics control unit 3
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
If no fault is stored:

- Press the ⇒key.

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.

Note:

If the self-diagnosis has not detected a fault, use the appropriate fault table in "Fault finding engine" binder for
further fault finding.

1.6 - Fault table

Notes:

◆ The fault tables are listed according to the 5 digit fault code on the left.
◆ Explanation of the fault types (e.g. "open circuit/short circuit to earth"):

=> Fault reader operating instructions

◆ If components are indicated as faulty:

First check the wiring and connectors to these components as well as the system earth connections ac‐
cording to current flow diagram. This is particularly relevant if faults are output as "occurring
sporadically" (SP).

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00626
Glow period warning lamp -K29
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Short to positive - Wiring short to positive agen
ksw - Warning lamp doesesnot no - Check K29, => Page
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ol
- Warning lamp ddefective
by
V light during glow period t gu7ar, final control diag‐
or
ise nosis
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ut or
ac
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V.A.G 1551 print-out Possible fault causes of
s Possible effects Fault remedy
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Glow plug monitor

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Open circuit/short to earth - Wiring open circuit or - Poor cold starting - Check wiring and connec‐
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short to earth - Glow period warning tions according to current

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- Fuse -S125- defective lamp (K29) flashes flow diagram.

hole

spec

- Relay contact open Replace fuse if necessary.

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Replace glow plugs if nec‐

t to the co

essary.
Short to positive - Wiring short to positive - Always pre-glows - Check wiring and connec‐
- Relay does not switch off tions according to current
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flow diagram.
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V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
01167
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Full throttle stop valve -

m

N194
com

tion in

Open circuit/short to pos‐ - Wiring open circuit or - Slightly reduced perform‐ - Check N194
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itive short to positive ance => Page 7 , final control

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iva

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- N194 defective diagnosis

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4 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
Short to earth - Wiring short to earth - Black exhaust smoke at
- N194 defective altitudes above 1000 me‐
tres
01168
Idling speed boost valve -
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Short to positive - Wiring short to dpositive
by - Idling speed too high t guar- Check N177, => Page
- N177 defective rise
when engine warm 7 t,eefinal control diagno‐
an
ho
aut sis or a
ss c
Open circuit/short to earth - Wiring open circuit - Idling speed too high

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- N177 defective when engine warm
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- Wiring short to earth - Idling speed too low when

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V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy

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spec
01169
es, in part or in w

Door contact switch driver's

t to the co
side -F2
Open circuit/short to - Wiring open circuit or - Glow period system will - Check wiring and con‐
positive short to positive not activate by opening and nections according to cur‐

rrectness of i
- F2 defective closing the driver's door rent flow diagram.
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Short to earth - Wiring short to earth - Renew F2 if necessary.

- F2 defective

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01170
m

Injection period sender -

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com

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G175

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Short to earth - Wiring short to earth - Automatic glow period - Check wiring and con‐

thi
s
control unit (J179) switches nections according to cur‐
iva

do
r

to emergency function rent flow diagram.

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No signal - Wiring open circuit or - Renew G175 if necessa‐

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short to earth . Cop
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- G175 defective
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V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
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01180
Engine / ACC electrical con‐
nection
Short to positive - Wiring short to positive - Check wiring and connec‐
tions according to current
flow diagram.
01204
Engine temperature sender -
G27-
Short to earth - Wiring short to earth - No pre-glow - Check G27
- G27 defective - No idling speed increase =>Page 33
when engine cold
Open circuit/short to pos‐ - Wiring open circuit or - Always pre-glows
itive short to positive
- G27 defective

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
01265
Exhaust gas recirculation
valve -N18-
Short to positive - Wiring short to positive - No exhaust gas recircula‐ - Check N18, => Page
- N18 defective tion 7 , final control diag‐
- Increased emissions nosis

1.6 - Fault table 5

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
Open circuit/short to - Wiring open circuit
earth - N18 defective
- Wiring short to earth - Exhaust gas always recir‐
culating
- Black exhaust smoke
- Increased emissions
- Slightly reduced perform‐
ance

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
01266
Glow plug relay -J52
Short to positive - Wiring short to positive - No glow period - Check J52
- J52 defective - Poor cold starting =>Page 7 , final control
- Glow period warning diagnosis
lamp (K29) flashes
Open circuit/short to earth - Wiring open circuit or
short to earth
- J52 defective

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
01269
Commencement of injection
valve -N108
Open circuit/short to pos‐ - Wiring open circuit or - Coarse engine running - Check N108, => Page
itive short to positive or diesel knock when en‐ 7 , final control diag‐
- N108 defective
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Short to earth Volks short to earth
- bWiring - Misfiring
ot gand/or blue
y ua
ris - N108 defective smoke whenraengine is
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1.7 - Erasing fault memory

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Special tools, testers and auxiliary items

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◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
es, in part or in w

t to the co

Test conditions
• Fault eliminated
rrectness of i
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Note:
After eliminating faults the fault memory must be interrogated again as follows and then erased.
nform
ercia

Work sequence
m

at
om

ion

- Connect fault reader V.A.G 1551 (V.A.G 1552) and with the "Address word" 41 select the Diesel pump
c

in t
or

electronics control unit. When doing this the engine should be idling.
his
ate

(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
do
priv

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for

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g

-> Indicated on display:

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Rapid data transfer HELP ht. rig
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Select function XX rig by
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- Press keys 0 and 2 for function "Interrogate fault memory" and confirm entry with Q key.
Prote AG.
-
Rapid data transfer HELP
Select function XX

6 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
-> Press ⇒key until all faults still stored have appeared and the display reads:
- Press keys 0 and 5 for the function "Erase fault memory" and confirm entry with Q key.

-> Indicated on display:

Rapid data transfer
Fault memory is erased!

- If the fault memory will not erase there is a fault still in the system and this must be rectified.
- Press the ⇒key.

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
- Carry out a road test and interrogate fault memory again. No faults must be displayed.

1.8 - Final control diagnosis

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
◆ Diode test lamp V.A.G 1527
◆ Adapter set V.A.G 1594
◆ Current flow diagram

The final control diagnosis activates the following components in the stated sequence:

1. Exhaust gas recirculation valve (N18)

2. Idling speed boost valve (N177) agen

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oes
(only with air conditioner) olksw not
y V gu
db a
e ran
ris tee
3. Glow period warning lampu(K29)
tho or
a ac
ss
4. Glow plug relay (J52)
ce
le
un

pt
an
d
itte

y li

5. Full throttle stop valve (N194)

rm

ab
pe

ility
ot

6. Engine/air conditioner compressor electrical connection

wit
, is n

(not relevant)
h re
hole

spec

7. Commencement of injection valve (N108)

es, in part or in w

t to the co

Notes:
rrectness of i

◆ The final control diagnosis can be carried out with the engine stationary or running. As the clicking of the
valves when being activated can be heard better with the engine stationary. it should be carried out with the
l purpos

engine stationary.
◆ The ignition must be switched off before repeating the final control diagnosis.
nform
ercia

Work sequence
m

a
com

tion in

- Connect the fault reader V.A.G 1551 (V.A.G 1552) and with ignition switched on select Diesel pump elec‐
r
te o

thi

tronics control unit using the "Address word" 41.

s
iva

(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
do
r
rp

cum
fo

en
g

-> Indicated on display:

n

t.
yi Co
Cop py
Rapid data transfer HELP t. rig
Select function XX gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

1.7 - Erasing fault memory 7

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- Operate fault reader taking into account the information on the display:
- Press keys 0 and 3 for the function "Final control diagnosis".

-> Indicated on display:

Rapid data transfer Q
03 Final control diagnosis

- Confirm input with Q key.

AG. Volkswagen AG d
agen oes
ksw
-> Indicated on display: byV
ol not
gu
ara
ed
Final control diagnosis ris nte
th
Exhaust gas recirculation uvalveo -N18 eo
a ra
ss c

ce
e

The valve will be activated and must click once.

nl

pt
du

an
itte

y li
erm

- Press the ⇒key.

ab
ility
ot p

wit
-> Indicated on display:
, is n

h re
hole

Final control diagnosis

spec
Exhaust gas recirculation valve -N18
es, in part or in w

t to the co
Valve activation will be switched off and the valve must again click once.

rrectness of i
Valve does not click:
l purpos

- Check exhaust gas recirculation:

nf
ercia

=> Repair group 26; Exhaust gas recirculation system; Checking exhaust gas recirculation Exhaust gas recir‐

o
culation system Checking exhaust gas recirculation

rm
m

atio
om

- Press the ⇒key. n in

or c

thi
te

sd
a

-> Indicated on display:

iv

o
r
rp

cu
o

Final control diagnosis

f

en
ng

t.
Idling speed boost valve -N177 yi Co
Cop py
ht. rig
ht
The valve will be activated and must click once.
rig by
copy Vo
by lksw
cted agen
Prote
- Press the ⇒key.
AG.

-> Indicated on display:

Final control diagnosis
Idling speed boost valve -N177

Valve activation will be switched off and the valve must again click once.

Valve does not click:

- Check wiring and connections according to current flow diagram.

- Check idling speed boost valve => Page 34
- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Glow period warning lamp -K29

The warning lamp must light up.

Warning lamp does not light up:

- Check glow period warning lamp:

8 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
=> Current flow diagrams, Electrical fault finding and Fitting locations binder

- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Glow period warning lamp -K29

The warning lamp must go out.

- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Glow plug relay -J52

The glow period is switched on and the relay must click

en AG. V
olkswonce
agen AG
ag does
ksw not
Vol
- As a check the diode test lamp V.A.G ed 1527can
by be connected to the glowgu
arplug
an feed wire.
LED must light up. thoris tee
or
- Press the ⇒key. au ac
ss

ce
e
nl

-> Indicated on display:

pt
du

an
itte

y li
Final control diagnosis
erm

ab
Glow plug relay -J52

ility
ot p

wit
, is n

The glow period is switched off and the relay must again click once or LED must go out.

h re
hole

spec
If the relay does not click:
es, in part or in w

t to the co
- Check glow plug system:

rrectness of i
=> Current flow diagrams, Electrical fault finding and Fitting locations binder
l purpos

- Press the ⇒key.

nform
ercia

-> Indicated on display:

m

Final control diagnosis

at
om

io

Full throttle stop valve -N194

n
c

in t
or

his
e

The valve will be activated.

at

do
priv

cum
or

- As a check the diode test lamp V.A.G 1527can be connected to the full throttle stop valve feed wire.
f

en
ng

t.
yi
LED must light up.
Co
op py
- Press the ⇒key. t. C rig
gh ht
pyri by
Vo
co
-> Indicated on display:
by lksw
cted agen
Prote AG.
Final control diagnosis
Full throttle stop valve -N194

Valve activation is switched off and the LED must go out.

If LED does not light up:

- Check wiring and connections according to current flow diagram.

- Check full throttle stop valve => Page 34
- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Engine/ACC electrical connection

1.8 - Final control diagnosis 9

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
The test step is also recalled on vehicles without air conditioner system.

- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Engine/ACC electrical connection

- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
Commencement of injection valve -N108

The valve will be activated and must click once.

- Press the ⇒key.

-> Indicated on display:

Final control diagnosis
End output

Valve activation is switched off and the valve must again click once.

Valve does not click:

- Check wiring and connections according to current flow diagram.

- Check commencement of injection valve => Page 32 .
- Press the ⇒key.

-> Indicated on display:

Function is not known
or cannot be performed at the moment

- Press the ⇒key. n AG. Volkswagen AG do

lkswage es n
o ot g
yV
-> Indicated on display: d b ua
ran
ir se tee
Rapid data transfer HELP tho
u or
Select function XX a ac
ss
ce
e
nl

pt
du

- Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
an
itte

y li

- Switch off ignition.

erm

ab
ility
ot p

wit
, is n

h re

1.9 - Reading measured value block

hole

spec
es, in part or in w

t to the co

Currently only display group 01 can be read in the measured value block, for the following values:
rrectness of i

Display zones
l purpos

1 4 2 3
Display group 01
nf
ercia

Display xxxx rpm xx.x ms xxx.x % xx.x mm3

orm
m

Indica‐ Engine Injec‐ Com‐ Quantity

atio
m

ted speed tion pe‐ mencement injected

o

n in
c

riod of injection
or

thi
e

valve
t

sd
iva

switched-
o
r
rp

cu

on period
o

m
f

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

10 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Test conditions

• Engine oil temperature min. 80 °C

• All electrical consumers switched off.

Work sequence

- Connect fault reader V.A.G 1551 (V.A.G 1552) and with the "Address word" 41 select the Diesel pump
electronics control unit. When doing this the engine should be idling.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display

Read measured value block 1
930 rpm - 37.0 % 5

- Read off idling speed in display zone 1.

Specification: 900± 30 rpm
- Disregard injection period in display zone 2 (no specification).
- Read off commencement of injection valve switched-on period in display zone 3.
Specification: 10...90%
- Read off quantity injected in display zone 4. swa
gen AG
. Volkswagen AG
does
Specification: 1...14 byV
olk not
gu
- If the specifications in display zone 3 and 4 are
risednot attained, replace injection period sender
ara
nte (G175)
=> Page 19 . utho eo
r a ac
ss
ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen

11
Prote AG.
1.9 - Reading measured value block
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

23 - Mixture preparation, Injection

AG. Volkswagen AG d
agen oes
olksw not
yV gu
1 - Servicing fuel injection system d b ara
ise nte
or eo
h
aut ra
c
1.1 - Servicing fuel injection system ss

ce
le
un

pt
an
d
itte

y li
erm

ab
Notes:

ility
ot p

wit
is n

◆ The control unit for the automatic glow period (J179) is equipped with a fault memory. Before carrying out

h re
ole,

repairs and fault finding the fault memory must be interrogated and final control diagnosis performed

spec
◆ During some checks it can happen that the control unit will recognise and store a fault. Therefore after
urposes, in part or in wh

completing all checks and repairs the fault memory must be interrogated and if necessary erased.

t to the co
=> Page 3 , interrogating fault memory
◆ Always renew spring-type hose clips with screw-type hose clips.
◆ Always renew seals and gaskets.

rrectne
Safety precautions =>Page 12

ss o
cial p

f
Rules for cleanliness => Page 12

inform
mer

Checking fuel system for leaks => Page 21

atio
om

n
c

i
or

n thi
te

sd
va

1.2 - Safety precautions

i

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
To prevent injuries to persons and/or damage to the injection and glow plug system, the following must be
ht. rig
rig ht
by
noted: copy Vo
by lksw
cted agen
Prote AG.
◆ The ignition must be switched off before connecting or disconnecting injection or glow plug system wiring
or tester cables.
◆ Before disconnecting battery, obtain radio code for radios fitted with anti-theft coding.
◆ Disconnecting and connecting the battery must only be undertaken when the ignition is switched off other‐
wise the automatic glow period control unit may be damaged.

1.3 - Rules for cleanliness

When working on the fuel supply/injection system, pay careful attention to the following "5 rules":

◆ Thoroughly clean all unions and the adjacent areas before disconnecting.
◆ Place parts that have been removed on a clean surface and cover. Do not use fluffy cloths!
◆ Carefully cover opened components or seal, if the repair cannot be carried out immediately.
◆ Only install clean components:
Only unpack replacement parts immediately prior to installation.
Do not use parts that have been stored loose (e.g. in tool boxes etc.).
◆ When the system is open:
Do not work with compressed air if this can be avoided.
Do not move vehicle unless absolutely necessary.
◆ Also ensure that no Diesel fuel runs onto the coolant hoses. If necessary hoses must be cleaned immedi‐
ately. Affected hoses must be replaced.

12 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.4 - Fitting locations overview

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

1 Exhaust gas recirculation valve (N18)

cu
o

m
f

en
ng

◆ Activated charcoal filter system

t.
yi Co
Cop py
t. rig
=> Repair group 26; Exhaust gas recirculation system Exhaust gas recirculation system
gh ht
pyri by
Vo
o
by c lksw
cted agen
2 Idling speed boost valve (N177) Prote AG.

◆ On vehicles with air conditioner

3 Automatic glow period control unit (J179)
◆ Location: above relay plate
4 Glow plug relay (J52)
◆ Location: on relay plate
5 Multi-pin connector

1.4 - Fitting locations overview 13

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
6 Engine temperature sender (G27)
ut
hor eo
a ra
◆ With coolant temperature
ss gauge sender (G2) c
ce
e

7 Injection pump
nl

pt
du

an

◆ Attaching components => Page 15

itte

y li
erm

ab

8 Injector
ility
ot p

9 Fuel filter
wit
, is n

h re

◆ Location: in front right wheel housing

hole

spec

10 Air cleaner
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

cu
o

m
f

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
o
by c lksw
14 23 - Mixture preparation, Injection
cted agen
Prote AG.
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.5 - Servicing injection pump

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c
ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
m

◆ Observe rules for cleanliness

o

n
c

i
or

=>Page 12
thi
te

sd
iva

o
r

1 Idling speed boost actuator

p

cum
r
fo

◆ Pneumatic for vehicles with air conditioner

en
ng

t.
yi Co
◆ Adjusting => Page 32 . Cop py
rig
ht
2 Bracket rig ht
py by
o Vo
3 10 Nm by c lksw
cted agen
Prote
4 Return pipe
AG.

◆ To control valve/fuel filter

5 Banjo bolt, 25 Nm
◆ Is marked with "OUT"
6 Oil seal
◆ Renew

1.5 - Servicing injection pump 15

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
. Volkswagen AG
gen AG d a oes
ksw not
y Vol gu
b ara
ed nte
oris eo
th
au ra
c
ss

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

7 20 Nm
8 Clamping piece
9 Banjo bolt, 25 Nm
10 Supply pipe
◆ From fuel filter
11 Injection pump sprocket
◆ Two part
12 25 Nm
13 Nut
◆ For hub, item 14
◆ Do not loosen. Otherwise the injection pump basic setting may be altered and this cannot be reset with
normal workshop equipment
14 Hub

16 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectne

15 Injection pump
ss

◆ Checking commencement of injection and adjusting =>Page 27

o
cial p

f i

◆ Removing and installing

nform

=>Page 22
mer

◆ Fill with Diesel before installing

atio
m

◆ On replacement, the injection pump must be matched to the electronic immobilizer

o

n
c

i
or

n thi
te

sd

=> Electrical system; Repair group 01; Immobilizer self-diagnosis; Matching fuel cut-off valve control unit to
iva

o
r

immobilizer control unit Immobilizer self-diagnosis Matching fuel cut-off valve control unit to immobilizer control
p

cum
r
fo

unit
en
ng

t.
yi Co
Cop py
16 Protective cap ht. rig
rig ht
py by
17 Idling speed boost actuator (N123) co Vo
by lksw
cted agen
◆ Electric for vehicles without air conditioner Prote AG.
◆ Adjusting => Page 32

1.5 - Servicing injection pump 17

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

18 Fuel cut-off valve control unit (J366)

◆ Checked by immobilizer control unit:

=> Electrical system; Repair group 01; Immobilizer self-diagnosis; Performing immobilizer self-diagnosis Im‐
mobilizer self-diagnosis Performing immobilizer self-diagnosis

19 O ring
20 Commencement of injection valve (N108)
◆ Checking =>Page 7 , final control diagnosis
21 Electrical wiring
◆ Removing from multi-pin connector => Page 25
◆ Multi-pin connector assignment:

=> Current flow diagrams, Electrical fault finding and Fitting locations

18 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

22 Injection period sender (G175)

◆ Tighten to 25 Nm
23 Shock absorber
24 Full throttle stop valve (N194)
◆ Checking =>Page 7 , final control diagnosis

1.5 - Servicing injection pump 19

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.6 - Servicing fuel filter

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
rise nte
tho eo
au ra
ss c

ce
le
un

pt
an
d
itte

y li
rm

ab
pe

ility
ot

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

1 Return pipe
◆ From injection pump
2 Supply pipe
◆ To injection pump
3 O-Ring
◆ Renew
4 Control valve
◆ Installation position: arrow points towards fuel tank
◆ When changing filter, remove securing clip and take control valve off complete with fuel pipes
◆ Below + 15 °C:
Passageway to filter open
◆ Over + 31 °C:
Passageway to filter closed
5 Securing clip

20 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c
ce
e
nl

pt
du

an
itte

y li
erm

ab

6 Return pipe
ility
ot p

◆ To fuel tank
wit
, is n

h re

7 Supply pipe
hole

spec

◆ From fuel tank

es, in part or in w

t to the co

8 Fuel filter
◆ Location: in front right wheel housing
◆ Fill with diesel before installing
rrectness of i

◆ Flow direction is marked by an arrow

◆ Do not interchange connections
l purpos

9 Gasket
◆ Renew if damaged
nf
ercia

10 Water drain plug

rm
m

atio

◆ To bleed remove securing clip and take control valve off complete with fuel pipes attached
om

n in

◆ Loosen and allow approx. 100 cm3 fluid to drain

or c

thi
te

sd
iva

o
r
rp

cu
o

1.7 - Checking fuel system for leaks

f

en
ng

t.
yi Co
Cop py
. rig
Special tools, testers and auxiliary items
ht ht
rig by
py
◆ Hand pump V.A.G 1274 co Vo
by lksw
◆ Adapter V.A.G 1274/1 A cted agen
Prote AG.

1.6 - Servicing fuel filter 21

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
◆ Adapter V.A.G 1274/2
◆ Hose clip

Test sequence
- Run engine at idling speed and open the throttle several times to remove any air which may be in the system.

olksw
- Disconnect return pipe from injection pump. agen
AG. V agen AG
does
ksw
- -> Secure adapter pipe to the injection
by Vol pump in place of the return
not
pipe.
gu
- Clamp-off supply pipe at fuel rtank
ised with a hose clamp. ara
nte
tho eo
au ra
- Using tester hand pump sbuild-up
s a pressure of c
1.0 ... 1.5 bar.

ce
le
un

pt
It may be necessary to pump up the system several times because of air which may be in the system.

an
d
itte

y li
- If the pressure constantly drops, locate leak and eliminate fault.
rm

ab
pe

ility
Notes:
ot

wit
, is n

h re
◆ The fault can be localised by repositioning the hose clamp, e.g. to in front of the fuel filter.
hole

spec
◆ The return pipe can be pressurized by connecting the adapter to the injector supply pipe. Then the return
es, in part or in w

and supply pipes at the fuel tank as well as the supply pipe at the fuel filter outlet must be disconnected.
t to the co
rrectness of i

1.8 - Removing and installing injection pump

l purpos

Special tools, testers and auxiliary items

nform
ercia

◆ Setting bar 2065 A

m

◆ Pin wrench Matra V159

a
com

tio

◆ Ring spanner 3035

n in

◆ Pin 3359
r
te o

thi

◆ Torque wrench V.A.G 1331 (5...50 Nm)

s
iva

do

◆ Spade terminal release tool

r
rp

cum
fo

en
ng

t.
yi
With engine removed:
Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

22 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
◆ Adjusting device 2068 A

Removing
- Remove intake hose between air cleaner and intake manifold.
- Remove upper toothed belt guard and cylinder head cover.
- -> Turn crankshaft to TDC No. 1 cylinder -arrow-.

Engine removed:

- -> Install adjustment device 2068 A as shown.

- Set adjusting device to 5 mm -arrow A-. The left-hand mark non
AGthe
. Volkscale
swagenisAG
the reference point.
- Turn crankshaft until flywheel TDC marking aligns with wage of setting devicedo-arrow
kspoint ot g B-.
l es n
Vo
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rise tee
tho or
s au ac
s

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le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectne
- -> Lock camshaft with setting bar.
- Centralize setting bar as follows:

s
Turn arrested camshaft so that one end of setting bar contacts the cylinder head. Using feeler gauge es‐

s o
cial p

f
tablish the gap at the other end of the setting bar. Place a feeler gauge corresponding to half the gap between
setting bar and cylinder head. Turn camshaft until the setting bar contacts the feeler gauge. Place a 2nd inform
mer

feeler gauge, of same thickness, at the other end between setting bar and cylinder head.
atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Lock injection pump sprocket with pin 3359.

- Loosen injection pump sprocket securing bolts -1-.
- Remove tensioning roller nut.
- Remove toothed belt from camshaft and injection pump sprockets.

1.8 - Removing and installing injection pump 23

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- Pull fuel supply and return hoses off injection pump.
- Unbolt all fuel lines at fuel pump.

Note:
Use slotted ring spanner 3035 to remove high pressure fuel pipes.

- Cover openings with a clean cloth.

- Pull accelerator cable off control lever and support bracket.
- -> Pull connector -1- off engine temperature sender and connector -2- off oil pressure switch.
- Pull connector off oil pressure switch on oil filter bracket.
- Remove wiring for glow plugs.

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agen oes
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ce
le
un

pt
an
d
itte

y li

- -> Disconnect multi-pin connector and unclip connector from retainer.

erm

ab

- Remove earth cable -2-.

ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

24 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- -> Remove securing bolts from console -arrows-.

Note:

On no account must the nut -1- for the hub be loosened. Otherwise the injection pump basic setting will be
altered and this cannot be reset with normal workshop equipment.

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
rise nte
tho eo
- -> Then remove bolt from rear support -arrow-.
s au ra
c
- Take off injection pump. s

ce
e
nl

pt
du

an
itte

Installing

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

-> If the injection pump is replaced, the spade contacts must be pushed out of the multi-pin connector with the thi
e

spade terminal release tool.

t

sd
iva

o
r
rp

cu
o

1- Spade terminal release tool

f

en
ng

t.
yi
2- Multi-pin connector
Co
Cop py
t. rig
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yri
Injections pumps supplied as a replacement part, are not fitted with a multi-pin connector. The spade connectors
p by
co Vo
by lksw
on the wires must be located in the multi-pin connector in accordance with the current flow diagram: Prote
cted AG.
agen

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

- Insert injection pump into console and then tighten securing bolt on rear support with conical nut first.
- Insert front securing bolts and tighten to 25 Nm.
- Fit bolts for securing injection pump sprocket to hub but do not tighten.
- Align injection pump sprocket to central position in elongated holes.

1.8 - Removing and installing injection pump 25

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

- -> Lock injection pump sprocket with pin 3359.

- Loosen camshaft sprocket securing bolt a half turn.

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c
ce
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un

pt
an
d
itte

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rm

ab
pe

ility

- -> Place a drift through hole in the rear of the toothed belt guard and release the camshaft sprocket from
ot

wit
, is n

camshaft taper with a blow from a hammer.

h re

- Check whether TDC mark on flywheel and reference mark are aligned.
hole

spec

- Fit toothed belt.

es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi
- -> Tension toothed belt. Using pin wrench (e.g. Matra V159) on eccentric turn clockwise until the notch and
Co
op py
the raised mark -arrows- align.
. C rig
ht ht
rig
- Tighten securing nut to 20 Nm. py by
co Vo
- Check TDC mark on flywheel again.
by lksw
cted agen
Prote
- Tighten injection pump sprocket securing bolts to
AG.

25 Nm.
- Tighten camshaft sprocket securing bolt to
45 Nm.
- Remove locking pin 3359.
- Remove setting bar 2065A from camshaft.

26 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- Turn crankshaft two rotations in engine D.O.R. until crankshaft is set to TDC No. 1 cylinder again.
- Check whether injection pump sprocket can be locked with pin 3359.

If the injection pump sprocket cannot be locked:

- Loosen injection pump sprocket securing bolts.

- Turn injection pump sprocket hub until the pin fits.
- Tighten injection pump sprocket securing bolts to
25 Nm.

- Fill injection pump with clean Diesel.

- Reconnect injection pipes, fuel pipes and electrical wiring.

Note:

Do not interchange fuel supply and return pipe banjo bolts the return pipe banjo bolt has a smaller internal
diameter and "OUT" is marked on the hexagon head.

- Install toothed belt guard, cylinder head cover and intake hose.
- Match new injection pump to electronic immobilizer.

=> Electrical system; Repair group 01; Immobilizer self-diagnosis; Matching fuel cut-off valve to immobilizer
control unit Immobilizer self-diagnosis Matching fuel cut-off valve to immobilizer control unit

- Check idling speed and governed speed => Page 30 .

1.9 - Checking and adjusting injection pump timing

Special tools, testers and auxiliary items

◆ Setting bar 2065 A agen

AG. Volkswagen AG d
oes
◆ Pin 3359 Volksw not
gu
◆ Torque wrench V.A.G 1331 (5...50 Nm) ed by ara
nte
ris
ho eo
ut
With engine removed: ss a ra
c

ce
e
nl

pt
◆ Adjusting device 2068 A
du

an
itte

y li
erm

ab
Test sequence

ility
ot p

wit
, is n

- Remove intake hose between air cleaner and intake manifold.

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

- Remove upper toothed belt guard.

um
for

- -> Check toothed belt tension. The notch and raised portion -arrows- must align.
en
ng

t.
yi Co
Cop py
If markings do not align:
t. rig
gh ht
pyri by
Vo
o
by c lksw
cted agen
Prote AG.

1.8 - Removing and installing injection pump 27

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- Adjust toothed belt tension:

=> Repair group 13; Dismantling and assembling engine; Removing and installing toothed belt and adjusting
tension. Dismantling and assembling engine Removing and installing toothed belt and adjusting tension.

n AG. Volkswagen AG do
lkswage es n
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byV ua
d ran
ir se tee
tho
u or
a ac
ss

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e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

- -> Turn crankshaft to TDC No. 1 cylinder -arrow-.

wit
, is n

h re
hole

Engine removed:

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

cu
o

m
f

en
ng

- -> Install adjustment device 2068 A as shown. yi

t.
Co
- Set adjusting device to 5 mm -arrow A-. The left-hand mark on the scale is the reference point.
. Cop py
- Turn crankshaft until flywheel TDC marking aligns with point of setting device -arrow B-.
t rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Check if injection pump sprocket can be locked with locking pin 3359.

28 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
If the pin cannot be pushed into the holes, the commencement of injection must be reset as follows:
- Remove cylinder head cover.

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
- -> Lock camshaft with setting bar. uth o eo
ra
- Centralize setting bar as follows: ss a c
Turn arrested camshaft so that one end of setting bar contacts the cylinder head. Using feeler gauge es‐

ce
le
un

pt
tablish the gap at the other end of the setting bar. Place a feeler gauge corresponding to half the gap between

an
d
itte

setting bar and cylinder head. Turn camshaft until the setting bar contacts the feeler gauge. Place a 2nd

y li
erm

ab
feeler gauge, of same thickness, at the other end between setting bar and cylinder head.

ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n
- Loosen camshaft sprocket securing bolt a half turn.
thi
te

- -> Place a drift through hole in the rear of the toothed belt guard and release the camshaft sprocket from
sd
iva

camshaft taper with a blow from a hammer.

pr

cum
r
fo

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

- -> Loosen injection pump sprocket securing bolts -arrows-.

- Turn injection pump sprocket hub until the pin fits.
- Check TDC mark on flywheel again.
- Tighten camshaft sprocket securing bolt to
45 Nm.
- Tighten injection pump sprocket securing bolts to
25 Nm.
- Remove locking pin 3359.
- Remove setting bar 2065A from camshaft.

1.9 - Checking and adjusting injection pump timing 29

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- Turn crankshaft two rotations in engine D.O.R. until crankshaft is set to TDC No. 1 cylinder again.

- -> Check whether injection pump sprocket can be locked with pin 3359.

If the injection pump sprocket cannot be locked:

- Loosen injection pump sprocket securing bolts.

- Turn injection pump sprocket hub until the pin fits.
AG. Volkswagen AG d
- Tighten injection pump sprocket securing bolts to lksw
agen oes
not
25 Nm. by Vo gu
a
ed ran
oris tee
- Install toothed belt guard, cylinder head cover
au and
th
intake hose. or
ac
ss

ce
e
nl

pt
du

an
itte

y li
1.10 - Checking and adjusting idling speed, idling speed boost and governed speed
erm

ab
ility
ot p

wit
, is n

Special tools, testers and auxiliary items h re

hole

spec
es, in part or in w

◆ Ignition tester V.A.G 1767 or V.A.G 1367

t to the co

◆ T spanner 3231

Checking and adjustment conditions

rrectness of i
l purpos

• Oil temperature at least 60 °C.

• Electric consumers switched off.
nf
ercia

Work sequence
orm
m

atio
m

The engine speed can also be measured in measured value block of self-diagnosis with fault reader V.A.G
o

n in
c

1551.
or

thi
te

sd
iva

o
r

- Connect ignition tester V.A.G 1367 or ignition tester V.A.G 1767.

rp

cu
o

- Start the engine and run at idling speed.

f

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

30 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
Idling speed
n AG. Volkswagen AG do
lkswage es n
o ot g
byV ua
d ran
ir se tee
tho
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nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
- -> Adjustment is by turning the idling speed adjustment screw -1-, with the T spanner 3231.

rrectness of i
Specification: 900± 30 rpm
l purpos

Idling speed boost

nform
ercia

When engine is cold or when switching on the air conditioner the idling speed will be increased by the idling
speed boost actuator.
m

at
om

ion
c

- Press lever against stop adjustment screw -2- by hand (when engine is warm). The engine speed must

in t
or

increase to

his
ate

do
riv

1050± 50 rpm.
p

cum
for

en
g

If idling speed is not to specification 1050± 50 rpm:

n

t.
yi Co
Cop py
t. rig
gh
- Release stop screw locking nut -2- and adjust increased idling speed to 1050 rpm by turning the stop screw.
ht
pyri by
Vo
- Lock stop screw.
co lksw
by
cted agen
- Check idling speed => Page 31 . Prote AG.

Engine governed speed (no load)

- -> Rev. up to maximum speed and set engine speed using adjustment screw -arrow- to
Specification: 5050 ±100 rpm
- Lock adjusting screw.

1.10 - Checking and adjusting idling speed, idling speed boost and governed speed

31
 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
. Volkswagen AG
1.11 - Idling speed boost oactuator
lksw
agen
AG does
not
yV gu
db ara
rise nte
tho eo
au ra
c
ss

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
When the engine is cold or when switching on the air conditioner the idling speed will be increased by the idling
speed boost actuator. If this actuator is replaced, it is to be connected as follows with the engine cold:
l purpos

Electrical actuator
For vehicles without air conditioner

nform
ercia

- -> Press control lever -1- against idling speed boost stop screw -arrow- and clamp clamping piece -2- so
there is no play.
m

at
om

ion
c

Pneumatic actuator

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

For vehicles with air conditioner

- -> Press control lever -1- against idling speed boost stop screw -arrow- and clamp clamping piece -2- so
there is no play.

1.12 - Checking commencement of injection valve

Special tools, testers and auxiliary items
◆ Hand multimeter V.A.G 1526

Test sequence

32 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
- -> Separate multi-pin connector -1- and unclip from retainer.
- Carry out resistance measurement between contacts 2 + 3 using hand multimeter V.A.G 1526.
Specification: 12 ... 20 ω

Multi-pin connector assignment:

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

If the specification is not attained:

- Replace commencement of injection valve (N108)

=>Page 18

n AG. Volkswagen AG do
lkswage es n
Vo ot g
1.13 - Checking engine temperature sender d by ua
ran
ir se tee
tho
u or
a ac
ss

ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness
Special tools, testers and auxiliary items

o
cial p

f inform
◆ Hand multimeter V.A.G 1526
mer

atio
om

Test sequence

n
c

i
or

n thi
te

sd
a

- Switch off ignition.

iv

o
r

- -> Pull connector -1- off sender.

p

cum
r
fo

- Perform resistance measurement between sender -2- sockets 1 + 3 using hand multimeter; Specification
en
ng

t.
yi
=> table.
Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
1.14 - Resistance figures for engine temperature sender
Prote AG.

Temperature Resistance figure Temperature Resistance figure

-20°C 5.40....7.30kω +20°C 0.922 1.158kω
-15°C 4.30...5.70kω +60°C 225...265ω
-10°C 3.30...4.30kω +90°C 96...108ω
-05°C 2.70...3.40kω +120°C 44.5...50.5ω
0°C 2.13....2.77kω

If the specification is not attained:

- Replace coolant temperature sender.

1.12 - Checking commencement of injection valve 33

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.15 - Checking idling speed boost valve

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c
Special tools, testers and auxiliary items

ce
e
nl

pt
du

an
itte

◆ Hand multimeter V.A.G 1526

y li
erm

ab
ility
ot p

Test sequence

wit
, is n

h re
hole

- Pull connector off idling speed boost valve.

spec
- -> Measure resistance at valve.
es, in part or in w

Specification: 50 ... 65 ω

t to the co
If the specification is not attained:

rrectness of i
- Replace valve.
l purpos

nf
ercia

1.16 - Checking full throttle stop valve

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

cu
o

m
f

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

Special tools, testers and auxiliary items

◆ Hand multimeter V.A.G 1526

- -> The naturally aspirated Diesel engines are equipped with a full throttle stop valve -1-. This is to reduce
the full throttle quantity at altitude.

Test sequence

- Perform resistance measurement with multimeter V.A.G 1526 between voltage supply connection and earth:
Specification: 8...12 ω (at room temperature)

34 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.17 - Residual volume basic setting

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
-> The residual volume screw -arrow- must rise
not normally be altered. nte
tho eo
au ra
ss c
The manufacturer sets the so-called residual volume via this screw on a test bench..

ce
e
nl

pt
du

an
itte

If the screw has nevertheless been altered, this may result in the following complaints:

y li
erm

ab
ility
ot p

◆ Screw turned in = residual volume too large.

wit
, is n

In this case the engine runs too fast and it is not possible to set idling speed.

h re
◆ Screw turned out (gap at adjusting lever) = residual volume too small.
hole

spec
This causes performance faults such as "flat spot" when pulling away and accelerating from low engine rpm
es, in part or in w

or jerking in all gears.

t to the co
If such faults occur, the following basic setting must be performed at the residual volume adjusting screw.

rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
iva

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r
rp

cu
o

m
f

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co
- -> Release adjusting screw -arrow- lock nut.
by lksw
cted agen
Prote AG.

Residual volume too low: (Performance faults)

- Screw adjusting screw in until idling speed increases.

- Turn adjusting screw back a half turn from the point at which the idling speed increases.

Residual volume too large: (Engine speed too high)

- Unscrew adjusting screw until engine speed no longer decreases.

- Screw in adjusting screw again until idling speed increases.
- Turn adjusting screw back a half turn from the point at which idling speed increases.
- Lock adjusting screw.

1.17 - Residual volume basic setting 35

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

1.18 - Removing and installing injectors

Special tools, testers and auxiliary items wage

n AG. Volkswagen AG do
es n
olks ot g
yV
◆ Ring spanner 3035 d b ua
ran
ir se
◆ Torque wrench V.A.G 1331 (5...50 Nm)tho tee
or
◆ Torque wrench V.A.G 1332 (40...200au Nm) ac
ss

ce
le
un
Note:

pt
an
d
itte

y li
Defective injectors cause the following faults:
erm

ab
ility
ot p

◆ Misfiring

wit
is n

◆ Knocking in one or more cylinders

h re
ole,

◆ Engine over-heating

spec
urposes, in part or in wh

◆ Loss of power

t to the co
◆ Excessive black exhaust smoke
◆ Higher fuel consumption
◆ Excessive blue smoke when starting from cold

rrectne
Defective injectors can be located by loosening the high pressure pipe union on each injector in turn with the
engine running at a fast idling speed. If engine speed remains constant after loosening a pipe union, this indi‐

ss
cates a defective injector.

o
cial p

f inform
Removing
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Remove injection pipes with a slotted ring spanner 3035.

Note:
Always remove pipe set complete. Do not alter pipe shape.
- Remove injectors with 27 mm socket.

Installing
Note:

36 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
Always renew heat shield between cylinder head and injectors.
-> Installation position of heat shield:
Arrow points towards cylinder head.
Tightening torques:
Injection pipes = 25 Nm
Injectors = 70 Nm
Note: agen
AG. Volkswagen AG d
oes
olksw not
Always renew heat insulating seal between cylinder
d by V
head and injectors. gu
ara
rise nte
tho eo
au ra
ss c
1.19 - Servicing injectors

ce
le
un

pt
an
d
itte

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rm

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Special tools, testers and auxiliary items
com

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r

◆ Torque wrench V.A.G 1332 (40...200 Nm)

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Work sequence
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en
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- -> Tighten injector upper part in a vice and loosen threaded union.
t.
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- So that the individual parts do not fall out, tighten injector lower part in vice and dismantle injector.
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When dismantling the injector ensure individual parts are not interchanged.
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Tightening torque:
Injector upper and lower parts 70 Nm

1.18 - Removing and installing injectors 37

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
-> Injector components
AG. Volkswagen AG d
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1- Injector upper part by Vo gu
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2- Shim orise
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3- Nozzle valve spring auth eo
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4- Pressure pin ss c
5- Nozzle valve retainer insert

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6- Nozzle valve (needle)

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7- Nozzle body
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8- Injector

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9- Heat insulating seal

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1.20 - Checking injector nozzle valve tip for damage, injection pressure and for leakage.

t to the co
rrectness of i
Special tools, testers and auxiliary items
l purpos

◆ Injector tester V.A.G 1322

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Checking injector nozzle valve tip for damage

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(Visual check)
or

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If injector nozzle valve tip is damaged e.g. broken off or deformed, renew injector or nozzle body and nozzle

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valve (needle).
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Checking injection pressure
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Warning!
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When testing injectors ensure that the jet of fuel does not contact the hands as the high pressure will cause
the fuel to penetrate the skin and may cause severe injuries.

Test conditions

• Pressure gauge on

Test sequence

- -> Connect injector to injector test unit.

- Move pump lever down slowly. When spray begins, read off breaking pressure. Specification incorrect;
adjust breaking pressure by exchanging shims.
Specification:
New injectors: 130 ... 138 bar
Wear limit: 120 bar

38 23 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
Note:

When servicing used injectors adjust breaking pressures to specifications for new injectors.

◆ Thicker shims increase breaking pressure.

◆ Thinner shims decrease breaking pressure.
◆ Increasing spring compression by 0.5 mm increases breaking pressure by 5.0 bar

Adjustment shims are available from 1.00...1.95 mm thick and increase by 0.5 mm. Use box 3065 to store
shims.

Checking for leaks

- Move pump lever down slowly and maintain a pressure of approx. 110 bar for 10 seconds. No fuel should
leak from the nozzle tip.

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at
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or

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1.20 - Checking injector nozzle valve tip for damage, injection pressure and for leakage.
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39
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 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995

28 - Glow plug system

1 - Checking glow plug system

1.1 - Checking glow plug system

Note: agen
AG. Volkswagen AG d
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The vehicles are equipped with a door contact controlled pre-glow
ised system. After entering the vehicleara the pre-
nte
glow system automatically starts on closing the driver's door.
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Checking door contact control:

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=> Current flow diagrams, Electrical fault finding and Fitting locations binder
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Test conditions

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• Battery voltage at least 11.5 V

spec
• Voltage exists at glow plugs. No voltage, locate fault according to current flow diagram.
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1.2 - Checking glow plug current consumption

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Special tools, testers and auxiliary items

nform
ercia

◆ Multimeter V.A.G 1715 or V.A.G 1315 A

m

a
com

tion in
Test sequence
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- -> Pull connector -1- off engine temperature sender -2-.

Note:

Pulling the connector off sender, simulates engine condition "cold" and when switching the ignition on the
relevant glow period is carried out.

- Place glow plug feed wire in multimeter current clamp.

- Switch on ignition to start pre-glow.
- Start the engine and run at idling speed.
- Read current consumption during extended glow period (approx. 180 sec.) with engine running.

40 28 - Glow plug system

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Edition 11.1995
The current consumption of the glow plugs during the extended glow period is approx. 8 Amp. per glow plug.
With a glow plug current consumption of:

Current consumption Defective glow plug(s)

32 A 0
24 A 1
16 A 2
8A 3
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Erase fault memory after completing checks ss a ra
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=> Page 6 . (The disconnected engine temperature sender connector is registered as a fault by the self-
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an
diagnosis) itte

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1.3 - Checking glow plugs
hole

spec
es, in part or in w

t to the co
Special tools, testers and auxiliary items

rrectness of i
◆ Diode test lamp V.A.G 1527
◆ Adapter set V.A.G 1594
l purpos

Test sequence

nform
ercia

- Remove wiring and busbar for glow plugs.

m

at
- Connect diode test lamp wire using auxiliary clips from auxiliary cable set to battery positive (+).
om

io
- Place diode test lamp probe on each glow plug one after the other.

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in t
or

Diode lights up: glow plug OK.

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ate

Diode does not light up: replace glow plug

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(tightening torque: 25 Nm)

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Notes:
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◆ The tightening torque of 25 Nm must not be exceeded otherwise the annular gap between glow pin and
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threaded section will be squeezed together. This may cause the glow plugs to fail prematurely. cted agen
Prote AG.
◆ If no fault is found and the engine is still hard to start, the glow plugs should be visually examined whilst
glowing (injectors removed).

1.4 - Glow plugs with burned electrodes

1.2 - Checking glow plug current consumption 41

 Caddy 1996 , Polo Classic 1996 ➤
Diesel injection and glow plug system - Editionag11.1995
en AG. V
olkswagen AG
do w es n
olks ot g
yV
Burned electrodes on glow plugs are frequently causedsedby faulty
b injectors. Damage of this nature
ua
ran is not due to
faults in or on the glow plugs. ho
ri tee
aut or
ac
ss
If damage of this nature is found -arrow- it is not sufficient merely to replace the glow plug. The injectors must

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also be tested for opening pressure and leakage => Page 37 .

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42 28 - Glow plug system