THE FUEL MANAGEMENT SPECIALISTS
Fuel Management System
Closed Loop Lambda Control Introduction:
Closed loop lambda control uses the Lambda sensor to check the exhaust o2
content and then changes the fuel maps accordingly. All the parameters are fully
configurable in the Gotech software. It is not recommended to use the closed
loop lambda control on turbo charged vehicles or more than 25% throttle on
normally aspirated vehicles.
The Lambda sensor must be mounted in the exhaust pipe near the exhaust
header or extractor, usually after the collector. The sensor uses the exhaust gas to
detect if the engine is running lean or rich.
The vehicle must be properly mapped on a rolling road before the closed loop
lambda control can be used. The recommended lambda sensor is a 4 wire Bosch
as used on the VW Golf vr6.
Colour codes for the Bosch four wire Lambda sensor:
White - 12v positive (Can be on either one of the white wires)
White - Earth (Can be on either one of the white wires)
Gray - Earth from instrument (brown / white)
Black - Signal (Black / Green)
Bosch 4 Wire
M18 x 1.5
Thread
WARNING:
A lambda sensor can easily be damaged by oil and debris in the exhaust system. Take care never to
drop the lambda sensor as it may lead to permanent damage. Most Lambda sensors are intended
for unleaded gasoline only and will not last long with leaded gasoline. Normally when a lambda
sensor packs up the reading goes to 14.7 and does not change when you enrich the engine.
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All Specifications Subject to Change without Notification Manual Version 06.01 2006/02/08
THE FUEL MANAGEMENT SPECIALISTS
Fuel Management System
Closed Loop Lambda Control:
Software Settings:
All of the closed loop lambda control settings are located in the f5 (settings)
screen.
1. AFR Preset (mv) Ideal voltage output on the lambda sensor, this
value is directly related to the air/fuel ratio. Best
would be to read the lambda manufacturer
specification on the lambda voltages.
Common values for a 4 wire Bosch sensor are:
Air/Fuel Ratio Millie Volt Output
14.7 AFR = 695mv
14.5 AFR = 795mv
14.0 AFR = 835mv
13.59 AFR = 855mv
13.3 AFR = 865mv
13.0 AFR = 870mv
12.4 AFR = 875mv
11.76 AFR = 880mv
890
0
5
88
0
87
5
87
86
Lambda MV
850
85
5
83
810
5
79
Air/Fuel Ratio
770
730
AFR
5
690
69
.7
.3
.4
14
14
13
12
Note: Always consult the lambda manufacturers specifications before use.
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All Specifications Subject to Change without Notification Manual Version 06.01 2006/02/08
THE FUEL MANAGEMENT SPECIALISTS
Fuel Management System
Closed Loop Lambda Control Continued:
2. Lambda Ramp Interval Controls the speed of the correction. A
lower value makes the correction happen
faster.
3. Lambda Limit Limit of fuelling adjustment allowed.
The higher the value, the more
adjustment will be allowed.
4. Lambda Switch Off Load The load site from where the closed loop
will be inactive. Eg load site 10.
5. Lambda RPM From which RPM the lambda sensor will
be active. Eg 2500rpm.
2
3
4
5
1
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All Specifications Subject to Change without Notification Manual Version 06.01 2006/02/08
