Scribd
Upload
545 views1 page

FMI 5: Checking The Injector Circuit FMI 7: Checking The Injector Circuit

The document discusses a malfunction in the electrical system of a vehicle with a fault code related to the injector circuit. There are two possible fault codes - one for an open circuit in the injector circuit and another for too high cylinder balancing data. The symptom is the engine running on 3 or 5 cylinders. Possible reasons include an open circuit in the cables to the injectors, a fault in an injector itself, or asymmetric engine loading. Suitable actions are to check the cables between the injectors and engine control unit, perform compression and cylinder acceleration tests to localize faults, and check individual injectors by changing them and performing injector trimming.

Uploaded by

user1
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
545 views1 page

FMI 5: Checking The Injector Circuit FMI 7: Checking The Injector Circuit

The document discusses a malfunction in the electrical system of a vehicle with a fault code related to the injector circuit. There are two possible fault codes - one for an open circuit in the injector circuit and another for too high cylinder balancing data. The symptom is the engine running on 3 or 5 cylinders. Possible reasons include an open circuit in the cables to the injectors, a fault in an injector itself, or asymmetric engine loading. Suitable actions are to check the cables between the injectors and engine control unit, perform compression and cylinder acceleration tests to localize faults, and check individual injectors by changing them and performing injector trimming.

Uploaded by

user1
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 1

Group 30: Electrical system Malfunctions, MID 128

FMI 5: Checking the injector circuit FMI 7: Checking the injector circuit
Fault code conditions Fault code conditions
Injector activated. Injector activated.
Open circuit in the injector circuit. Too high cylinder balancing data.

Symptom Possible reason


The engine can run on 3 or 5 cylinders. ● Poor compression.
● Fault in injector.
Possible reason ● Asymmetric engine loading*.
● Open circuit in the cables on the low voltage or * If the engine is asymmetrically loaded and a fault code occurs,
high voltage side. it is not possible to rectify the fault code since there is no me-
chanical fault.
● If three fault codes are set (one bank), the open When the engine idles, the engine control unit attempts to com-
circuit is in that bank’s high voltage side. pensate for uneven running by supplying more or less fuel to
the injectors, so-called cylinder balancing. If the asymmetric
● If there is only one fault code, the open circuit is loading is to large, the engine control unit’s attempts at compen-
on that injector’s low voltage side. sation will not be enough, the engine will run unevenly and a
fault code will be set.

Suitable action Suitable action


1 1
Check the cables between the injector and the engine Do a compression test and a cylinder acceleration
control unit. test, using Vodia, to localize the fault source.

2
Check the injector by changing the injector.
The injectors are manufactured with tolerance classifi-
cation. When an injector is changed, a task called ”In-
jector Trim” must be done. The trim value is noted as
a code on the injector’s electric conector, consisting
of up to 6 characters. The trim value is programmed
by Vodia and is only done for the cylinder whose unit
injector has been changed.

91

You might also like