Brought the car in to my mechanic because its been a month and I can't figure this out.
He said MAF is reading 38 GPS at 2400 rpm and that it should be reading 4 GPS.
I found this to sound misleading, what should a typical reading at 2400 rpms be? I heard it should be 2-4 GPS at IDLE so 38 GPS sounds about right for 2400 rpms....Any help?

1.8T early 99' A4 Quat

There is evident raw fuel burning on the Cat, I smell it whenever I park the car after it starts to stall out.

 

Come on guys....

Here's some more info. I brought it in to diagnose a problem with the idle where it would drop way down to almost stalling but WOULDNT stall, and then would over compensate to about 2000 rpms on its own. Also would sometimes leap forward or feel a cut in power during acceleration. I've replaced the TB and clutch and the mechanic told me he smoked it for 30 minutes and found no leaks.

 

Hey one last LITTLE thing to check! Please have this part at least looked at and dont ignore my advice because it may seem silly. But all turbo cars have a wastegate/diverter valve/ BOV. After a while these can get clogged. On stock audis you have a wastegate. A wastegate is a "gate" that opens when your turbo is not spooled to let excess air out of the lines, and closes when the turbo is spooled so all the air goes to the turbo.

If it gets clogged the extra air in your turbo line can not be released thus causeing it to build up and make back pressure. This back pressure causes the engine to stall or die because it is not being used by the turbo. This is because the turbo is connected to your side mount intercooler, which is connected to the intake madifold.

Its a simple job to do. You just remove the wastegate and clean it out with an air tool or something.

Having this clogged would cause RPMs to drop at a stop after the turbo has spooled up. and the power lag when your trying to accelerate is do to the waste gate not closing and air escaping.

 

Awesome, thanks for the suggestion. Where is this located I don't have a manual with diagrams but I know a good amount about cars.

 

Check for codes, even if you don't have a CEL.

 

Senior Bradfish...
I am running a stock '00 1.8t (ATW), and recently purchased a vag-com in response to a CEL. One of my engine faults noted "Fuel Trim; Bank 1 (Mult): System too Lean P1128 - 35-00 - - " which pointed to a possible MAF failure.

I then did two tests to check on my MAF health: 1) looked at measuring block 32, and noted that the part throttle Lambda was over 20% (s.b. +/- 10%) and 2) logging my air mass drawn in (g/s) while going from 900 to 6600 in second gear (that was fun!!).

I expected 120 g/s under full load buy only got 95 or so. I removed and cleaned the MAF, reinstalled and then did the same test. Results improved, but still not up to spec., so I replaced the MAF with a Bosch rebuild (110 here). Full throttle mass air now taps 135 or so, and my p throttle lambda is -2.5%. Both good!

Now during the full throttle test, my mass air is 3-5 during idle, reaches 23 @ 2560, 48 @ 2720, 66 @ 3040 etc up to 135. Note that as soon as I take my foot of the peddle, the mass air drops to 5-10 even though the engine is still turning around 4600 and slowing down.

Hope that this helps.

 

i was going to say i only note maf voltages when testing.. which is what the ecu sees... im not good at all with grams per second or what ever it stands for.. i guess theres always something new to learn... eh??

 

Well thanks for all the help guys, I think I'm just gonna redo the MAF since its cheap and fails often anyway....I'll have them blow out the N75 while I'm in there anyway.

Cheers

 

MAF fixed it YAY! Haven't driven this beast in 2 months!

 

nice