Lambda sensor??

[NovaB3ast]

Explain how this works......
I've got a fuelling problem and think it might be down to a sensor but don't know which 1

[Adam]

Basically, it senses the amount of oxygen in the exhaust gases.

If it senses that not all of the air in the mix is being burnt then the mixture is lean, so it sends a voltage signal to the ecu to richen the mixture slightly.
If it senses a low amount of air then its a rich mixture.
IIRC, the amount of air in the exhaust gas is proportional to a voltage that the lambda produces, this voltage is then fed to the ecu, which then adjusts the fuel/air mix until its spot on.

What engine do you have?

[TommySR]

K, heres a question, recently had a 4 Branch manifold and full stainless system to my 1.4SRi which had a Lambda Sensor. The sensor was part of the old manifold which has been removed and ive noticed no difference in engine performace (maybe perhaps slight increase). The engine management lights comes on after roughly half hour plus of driving but makes no difference in performace, if the ignition is turned off and then back on again the lights turns off..??

[Adam]

IIRC
The ecu only uses the lambda when the engine is warmed up, it ignores it when the engine is cold.
You should notice that your MPG will decrease without the lambda sensor. And the ECU light will keep coming on.

[Adam]

Theres a better explanation here:-
http://www.migweb.co.uk/forums/showthread.php?t=151693

[NovaB3ast]

Well my scenario is the same, I've fitted a four branch and now the engine management comes on after a bit of driving but after I stop the car it wont start till it cools down for half an hour........
I thought it might be something to do with the lambda sensor but will try a few different things people have mentioned.
cheers

[TommySR]

Havent had the same trouble with it not starting??

Let us know if anything happens mate as we are in the same boat lol

[Adam]

A lambda sensor wont stop the engine from starting.

[NovaB3ast]

A lambda sensor wont stop the engine from starting.
Well that rules that one out then.....