rn3037

MAF UNPLUGGED RESULTS
The MAF that was currently in this car was from my 2006 A8L that had no issues. Also note, the car ran exactly the same with the MAF unplugged because when I plugged it back in, the RPM and engine sounded the same.

***Air Fuel Lambda was on the rich side which is expected from the unplugged MAF. Then the O2's came on and went to MAX of NEGATIVE 25% because of the rich condition. This looks like normal behavior.

***BLOCK 107 PASSED! On paper this is basically saying the Fuel Control (Lambda Sytem) is OK with the MAF unplugged, but it's NOT OK with the MAF plugged in. For the "System" to not be OK with the MAF plugged in, that sounds like a MAF to ECU communication/data interpretation problem possibly?

Anthony4196

I am getting these same lean codes..

dvs_dave

Have you tried swapping the throttle body? If when the good maf is plugged in it goes lean then perhaps your TB is out of whack and letting too much air through?

rn3037

That's a good point! This throttle body and intake manifold are actually from another car but I had the same exact codes with the original intake/throttle body too. I'll try doing the TB adaptation again and go from there.

Well both MAF's are 'good' - the 10%+ fuel corrections that are causing the lean codes don't happen with the MAF disconnected which is odd. I'm really wondering why Block 107 passed basic setting with the maf disconnected but it fails every time with the MAF connected.

Anthony4196
These are tough codes man, 90% of the remedies for these codes is a vacuum hose leak or the MAF from what I've seen.

Anthony4196

Thanks guys! I will try looking for vacuum leaks and try switching the maf. I will let you know what I find..

My check engine light only comes on about every 500 miles with these codes for some reason. I will clear the codes and then they won't come back for around another 500 miles.

rn3037

Are there any other codes along with P1136 / P1138? Hmm yea mine comes back between 8-20 miles. Yours may be more intermittent.

rn3037

I just ordered a Coolant Temp Sensor for my car. Can't think of anything else that would cause the fuel trims to be high only before the car is warmed up.

Anthony4196

Just P1136 and P1138.. Maybe it is a tiny vacuum leak somewhere..

aTOMic

Isn't it funny how hard it is to do WOT runs in these cars ('cause they're so fast)?
I needed to pull to the side of the highway to start (OK, I wanted acceleration time as long as it required me to go 5000+ RPM) and she was still only in third, I think, when I had to let off. Next requirement per Audi TSB* was letting it idle for three minutes after highwat speed;I was doing that off a side road and the trooper who was patrolling that stretch said "yeah, first I saw you holding up traffic northbound (Audi drive cycle says go 45-55 for ten minutes, I think). "Then I see you Southbound from (an unfinished road I pulled off into) like a bat-outta-hayull, now you're sitting here with your flashers on again." (I had pulled into another new side street which lead nowhere.) showed him the laptop and drive cycle I'd printed out and he understood.

The manifold changeover happens at 5K RPM, FWIW. Do you ever get to that range? could have something to do with that.

I'm pretty sure that you can see all the coolant temp sensor readings in "Advanced Measuring Blocks".

There was some other member who found those same DTCs to be caused by his air filter housing being misassembled after an oil change. The outside did not seal - they had just left a big gap where one screw didn't find its hole.
I'd also check the aux/secondry air pump connections and operation, while you have the housing out. Hafta get at it from the bottom, I'm afraid.

*TSB detailing drive cycle to set readiness codes. Didn't work for me - twice - despite being followed exactly, but the next day my wife took it on a 60-mile road trip and it was ready then!

Tom

rn3037

Tom,
Thanks for the reply and glad that trooper understood what you were doing! Yea the readiness takes longer sometimes, I guess you have to hit different rpm ranges for it to pass or check everything.

Secondary Air Pump
I'm pretty sure mine is broken or the relay isn't working, BUT I capped off the SAI solenoid valve vacuum lines so if the pump had a leak itself it would by bypassed. It didn't make a difference, the car was still adding fuel on the cold start.

The intake airbox is another good point, mine wasn't screwed down all the way either but that is air before the MAF so it shouldn't have any impact on the addition of fuel on the cold start especially the fact that once the car warms up, it just stops adding 10+% fuel, that is the strange part.