Just bought an 04 A8 with 206K at an online auction sight unseen. Car has NOT been well maintained. When I get the car, is starts and runs OK, but barely wants to accelerate when giving it throttle. Feels like a Bad MAF sensor. So I unplugged the MAF sensor, no change. Cleaned the MAF sensor, no change. Bought a new MAF sensor off the internet and installed it, No Change. Sent to car to Independent VW/AUDI shop for a diagnostic and they came back with the following Diagnosis: Replace both Fuel Pumps and both o2 sensors under the manifold. Here are the fault codes from VCDS:
P1130-System Too Lean Bank 2
P1128-system Too Lean Bank 1
P0113-Intake Air Temp Sensor Signal Too high
P0102-Mass Air Flow Sensor Signal Too low
P2234-Signal Shorted to Heater Circuit Bank 2 Sensor 1
P2415-Intermittent Bank 2 Sensor 1 Voltage too Low
P1575-Engine Mount Solenoid Valve Short to Plus


Grand Total of $3300 to fix everything including Engine Mount and o2 sensors.


OK. Not doing that!! So the Shop Manager explained the car has 2 Fuel Pumps that work together. Neither is Functioning properly, hence the Lean Codes on both Banks. Need to Replace both. Also need to replace both o2 Sensors under the manifold. And after that, see if the car runs properly without replacing the MAF sensor(still may be good).


I Responded, the car still runs and idles on it's own, how can both pumps be bad? He says he always replaces both, never seen replacing one pump fix the problem.


I don't want to spend a ton of the money on this car, since it was somewhat beat up by the previous owner. But I do want it running and driving normally. Not Chugging and Spitting when I hit the gas!! I'm not saying the Shop is wrong? But I don't understand the car needing both fuel pumps when it does run. Could the MAF harness and wires be frayed or split somewhere down the line causing the MAF not to operate properly or not at all?


Is there a sure fire way of testing the pumps? I read something about unplugging the right(main) pump. see if the car still runs. And do the same thing to the left side. Could the o2 Sensor code have the car running this bad or is that just an systematic error code related to the fuel or MAF? I don't mind replacing both fuel pumps if that IS actually the problem. I don't believe in throwing parts at a car until I know that I know that's the issue. And the Shop Manager just seemed to be basing his diagnosis off the codes only. They mainly deal with VW's. But They did fix my last A6 a few years back. What are the codes pointing to?


I want to get this car on the road for as Less as possible. No offense to the Enthusiasts out here.

 

I had an issue with mine about 4 years ago that turned out to be a small crack in the rubber fuel line from the pump (my 2003 has a single pump set up) to the outside connection inside fuel pump assembly. I had replaced the pump but didn't notice the crack in the rubber line. Pulled it back out and found the crack. Replaced the 6-8" long hose (make sure it's the "IN TANK" rated hose) and haven't had an issue since. If you do pull the fuel pumps, do yourself a favor and get the o-rings that seal the pick-ups and a new seal for the assembly where it fits in the tank itself. Ask me how I know..

HTH,
Dave