MP4.2+6.0

aka the "smog pump" in 70's terminology. Audis use an electric pump (two on W12 and likely two on S8 as well) to drive extra air into ports in the exhaust area of the heads when the car is cold. Injection then dumps extra fuel along side, which then burns in the upper manifold area in front of converters and causes them to light off (perform) quicker, since most motor emissions are now in the cold start phase.

From my C5 4.2 experience the air injection system is often a culprit on the kind of codes you have, but also hard to get nailed because the codes are right at the intersection of several systems. If it is the air pump system, it is commonly a cracked or broken hose between the pump(s) and the head/manifold areas where the control/check valve is. 4.2's at least used to have (on C5's) vacuum lines that drove it through combi(nation) valves that also dealt with EGR, but at least on the W12 those two systems seems to be separated and the air injection switching seems to now be via the pump itself in combination with a one way/check valve up by the front of each head.

dcc1433

Thanks SaltyI, yea I gave praise where it was due when they offered to pick up all labor costs because at the point the car was there 12 weeks, maybe 14. I like the group in general but what I don't agree with is they charge you even if it doesn't fix the fault code issue, and they hide behind we have to do what Audi of America says to do. And I am grateful for the loaner, would be significantly worse if that wasn't available.

Eurotech is fabulous…….but on this mess I didn't want to burden Brian with the headache.

Thanks, week number 2 no word on car, going on week #3. On top of 12 or 14 lost count.

dcc1433

Thanks I have passed this along to JE Audi just as an FYI in case they didn't look at that yet. Thanks for the explanation.

SaltyIrishman

Jeez. I have a feeling that a lot of the newer cars that dealerships have to deal with are basically just a big question mark and it's the "let's throw parts at it" mentality rather than good old fashioned wrenching.

dcc1433

For those of you still following this saga, I just picked up the S8 yesterday after another 3 weeks in the shop. Turns out after more extensive testing that the Intake Manifold had a crack.....failed part according to AoA. So, I must give JE Audi and AoA a thumbs up since they covered the $3750 part and labor. So it would appear that after many months of chasing the original issue it is finally corrected.

The only reason why I won't give JE Audi 2 thumbs up is because when I picked the car up yesterday the tank was below E running on fumes and they said I needed a new battery and to drive it for a bit to recharge it since it's been sitting. They jumped it before bringing the vehicle out. So it was "hey here's your car, you may need a new battery soon, but drive it a bit". It was dead as soon as I shut the car off. So I spent the afternoon finding a new battery and replacing the old. Thank God for my Indy Shop Eurotech.

Battery Note for S8's D3: If Audi doesn't have in stock check VM dealership. That's where I picked mine up, same part number, same day....it's a beast cost $207.00. I purchased the OEM again because my old OEM battery life was 7 years....tough to beat.

Thanks again to all for the help. The forum has been tremendous in helping me pin down and solve the issues. At this point, everything has been done to the engine except a new block so it looks brand new when you pop the hood.

haggisuk

Great that you got your car back, but what about the other 3k you poured down the drain.

Did they give that back to you?

dcc1433

Attachment 44010Nope, their official statement was "the work was needed" and "we don't guarantee that the repairs will fix the problem"...yes, I got that one at one point.

Thought I should up-load some pics of the beast....shots taken before I lowered and added 15mm/12mm spacers.

dcc1433

Finally, problem solved. Was definitely a bad intake manifold which AofA covered since only 53,000 miles on car. This appears to have been the problem all along. Drives and runs beautifully now like it should. Happiness!

SaltyIrishman

Glad you're back and enjoying the car--and that Audi at least tried to help and covered some of the costs...

dcc1433

Thanks Salty I. Best it's ever run. Smooth as silk and performance is where it should have been all along. Jury still out for me on the JE Audi Marietta shop but hear the one off Peachtree Industrial was the place to go for this car. Live and Learning still…….

Thanks!