Hi guys,

I can't seem to get a response out of the allroad specific section, but I believe these systems are similar if not identical. Perhaps one of you A6 guys can help me out with this:

Specimin: 2005 allroad with 130,000 miles. No CELs.

Symptoms:

1. Came out of store, car would crank but not start. After several minutes of furious thinking, I tried banging on the gas tank just in front of the passenger's side rear wheel. Car started right up and was problem free for a few days.

2. Sitting at a drivethrough window and the car stumbled and died. Refused to restart, even after banging on gas tank again. Towed home.

3. I was sick for a bit, so figure a 10 day lapse with the car just sitting in the driveway. I go out, and it still refuses to start. Bang on tank, starts up after a second so I can reposition the car in the driveway.

4. The next day, it again refused to start. Tried nothing, just left it alone so I could consult with you bunch of experts.


So, my conclusion is that the fuel pump is at the end of it's life. Banging on the tank can "jar" the pump back into temporary service, but obviously is not dependable.

Question #1: Is there anything else I should check before blaming the pump?

Question #2: Anybody got a writeup on replacement?

Question #3: Is there a cheaper alternative pump than stock that can be easily used?



Thanks for your assistance guys. Much appreciated.

 

Anybody?

 

Well, you seem to be on the right track. Mine is a C5 but I think there's not that much difference in the pump in the C6.
How full is your gas tank? Several people have reported loss of fuel pressure below 1/4 tank - apparently the fuel pickup line inside the tank can come loose from the bottom of the tank and float upwards enough that it sucks air when the tank gets low.
You should be able to hear the fuel pump run when you turn the key, at least for a few seconds. If not, you could check the connections at the sender/pump to make sure power is getting there and the connections aren't corroded, etc. You access the pump through a panel underneath the rear seat in an A6; not sure if yours is the same or not.
Otherwise, you can check the fuel rail pressure to see if fuel is getting there, but you need a gauge tool to do that...
Jim

 

If you want to be for sure, then test the fuel pressure while cranking. You should get around 50 to 60 PSI.

 

Sound like the fuel pump has started counting its days. Check your fuel pump.

 

Thanks guys.

 

It just so happens that she's right at about 1/4 tank right now. I think I'll throw a few gallons in, and then see what she says. Thanks for the insight Jim.