Fuel Pump Blues, take TWO.

[adjuster]

Update: So, the saga might finally be over.

I had added the in line, external Walbro 255lph metal pump, and it works fine. I have it wired in with the stock pump, seems to work great. It does make noise, while the stock one is totally silent on my 2001 S8, and has been from the time I bought it with 75k.

So, the CEL was still flashing, and the random multiple misfire deal where it drops out a few injetors until you shut off, and restart the engine...

I talked to my local Audi Dealer mechanic, who is the only mechanic I trust locally. (Have worked with a few now, and Kevin is the best one locally, and a really helpful guy as well.)

I went over with him what I've done, and he asked me to pull up measureing blocks 15, 16 and 17 while the engine was running.

He also said the AFM might be bad, and that was block 32 IIRC. (Did not show values that it's failing, so the AFM is fine.)

BACK TO THE STORY So, I pull up the measuring blocks, toggle up to the right numbers, and there you go, all 8 coils in real time, showing any misfires.... And BOOM!

At idle. All zero's.
At 2500RPM, #8 starts to show 50 or more.. At 3k, it's 80, and #1 and #7 have joined in, and are showing misfires as well.... By 5k, they all are over 100, and #8 is 250+...

So, clearly based on this test, I have three bad coils, and the worst of the bunch is #8, followed by #7 and #1 in a tie for second worst...

I have three new coils now on my kitchen counter, from RockAuto.com for just over 15.00 each. They don't have the rubber o-ring, but I can either use the existing ones, or buy new ones for a few bucks tops. The coils are black v/s natural potting material color, so it will be easy to keep tabs on what coils have been replaced.

I re-set the VAG Comm a few times, and cleared all the codes, and guess what folks?

NO MORE CEL FLASHING, and the car runs fine up past 85mph. (Fastest I have pushed it in the past few days around here in the city.) Downshifing into a lower gear, and running it at 6000RPM does not flash the CEL either.

So, I plan on changing out the coils I know are failing just because I know they are failing, and it was less than 55.00 shipped to me from Rockauto.com for new coils. (Standard parts brand.)

Any thoughts? I am VERY happy with the easy external fuel pump fixing the fuel flow/pressure problem, clearly there is no more CEL, but I'll change out the coils that have more misfires just because I think it will smooth out the engine, and perhaps improve fuel economy, and at today's gas prices, the 55.00 will come back pretty quick with a few mpg improvement.