Mister Bally

A low price is soon forgotten when poor quality rears its ugly head.
You will be doing the repair job twice and realize you wasted money on the first part purchase. It is not worth it.

That said, I don't like it when someone tells me how to spend my money. If OEM or OES (here, Bosch) prices are too high, Drive the car as is with the MIL and poor performance/fuel economy until you can buy the correct part.

jeffkruse

I am not sure this is a very good test or not, but I heard if you unplug you MAF and if it runs better then it is your MAF. The test I performed with my VAGCOM indicates MAF, but when I unplug the car runs considerably worse. So is that an indication that it is NOT my MAF?

Jack88

That sounds like something someone told you who's used to wrenching on Fords. I'm not intimately familiar with Audi's engine electrics, but that doesn't sound right to me.

MP4.2+6.0

Normal fuel set up on a car will have the default mode run as close as possible to 14:1 stoichiometric and generally smoothly. So if it runs lousy with MAF unplugged, that suggests to me if anything the MAF is counteracting some issue that is causing air:fuel to be fairly far off where it should be.

jeffkruse

I performed the test in VAGCOM for Group 002 in the engine module, Is there any other test? I hate to just throw 150.00 here 150.00 there if there is another test I can perform.

My results from the first test

RPM MAF
6040 184.25
6480 186.69
6000 182.1

MP4.2+6.0

In plainer English, your measured flow rate sucks. Flow by rule of thumb should be 80% of peak HP measured in g/s. You aren't even close. Move on past the keyboard and replace the MAF given that. Diagnostics aren't more precise than that, so if you are expecting to run the x23yz slash 1, rev. 4.34567 test and get the answer that it is 100.0000% the MAF and not the franistan alternative or the flux conductor or whatever, not even close to the degree of precision in even the VCDS world.

Someone else (?) is also posting on QW with possible MAF issues on his 4.2 is at least up to around 240 g/s, which would tie to around 300 rated HP by the 80% rule of thumb ( I saw up to about 255 with a replaced MAF on my 2000 A6 4.2 which was actually rated at only 300HP). D3 A8's are somewhat more rated HP. Since his is somewhat low by the rule of thumb per his graphed data, yours is apparently sucking even proverbially (less) wind (that it is misreading) comparatively, same motor to same motor. quattroworld.com Forums: Input on recurring lean condition B1

jeffkruse

OK thanks MP4.2, I am ordering a Bosch as I type. Thanks again

jeffkruse

and the readings are the same as my old bosch on vehicle now. Is it possible that I got a bad new one? Or maybe is it something else. Below are the readings with the brand new MAF sensor

Rpm's MAF readings

6040 184.25
6480 186.69
6000 182.11

dvs_dave

Check that the throttle body is working properly and not only partially opening.

MP4.2+6.0

I thought from my prior comment on the load reading from a couple of messages earlier--which dropped out of the more recent measurements--that this was resolved. But I guess not. Load reading from earlier when it was only about ⅔ wasn't right. Check it again (or maybe you already have it?) If still only in the 60-70% range max, something would seem to backing the throttle off if MAF isn't misreading. That leaves things like throttle itself (IF it is getting the 90-100% expected signal on pedal to metal but is simply malfunctioning), faulty electronic pedal, maybe way out of whack knock, temp or other sensor inputs, or assorted other variables that inform the ECU what to in turn tell the throttle body to do.