desperate after some help

[urquattro-island]

Hi well we are working on my old s4 aan engine, and its having idle problems. I had a faulty maf on it changed it,and ran fine for about 5min. Then its going up and down up and down.. from 500-1000rpms. Any ideas, the maf is new, new boost hoses, new sparks and coils, its only on idling??
And when i take off the new maf, it runs fine on idling again
its a little mistery for me.

[BRY]

Clean the contacts in the plug.

[Flat on my back]

Only at idling?

Maybe lambda.

[saltinot]

Maybe lambda.

I agree.

I have cured idle trouble on my AAN which replacing the lambda and cleaning the ISV.

[S4 driver]

had the same problem and the cure whas new lambda

greets

[urquattro-island]

ok

dissconnected lambda and it runs even worse, seems to be somthing else??

[k.alle]

dissconnected lambda and it runs even worse, seems to be somthing else??

Don't disconnect it, if you want to check the status of the lambda measure it!
It's easy and done in 2 minutes.

This is how:
1. one warm car
2. a buddy that holds the revs at 2.000rpm
3. you standing and measuring the probe, pull back the rubber boot on the connection to the ECU and let it be connected!
Now measure the Voltage (DC) between this connector and a good ground.
A healthy lambda should jump between ~0.3V to ~0.8V (by that I mean lover and higher than 0.5V).
It should jump between these rates at least 8 times in 10 seconds, if it sits still or is too slow it's smoked.

The key here is lower and higher than 0.5V.
0.3 and 0.8 are not some absolute values that it has to reach.

It's much much much easier to do than to as a Swede describe this procedure in English


Good luck!