Dr. A8

I confirmed yesterday that it is indeed the fuel pump. After putting the injectors back in and cranking I cracked the fuel line open and almost no gas dribbled out. Looks like I will be replacing a fuel pump in the parking lot at my office. I watched a video and read some threads on how to do it. Looks like this will only cost me about $350 to get done unless anybody knows a cheaper alternative to the $200 seal kit.

jfrahm

I have not bought any gaskets just did the pump and re-used everything. If I did it again I might get the big one: 1J0919133A, 4D0919133E, 321919133

https://www.europaparts.com/fuel-pum...j0919133a.html

Watch for cracks around the long bolt mounting point, I have had to butter these with RTV or JB weld to get it to seal and not throw codes. I saw the cracks on my S8 before it had ever been apart so it wasn't due to my wrenching.

Dr. A8

Thanks for the info Joel, I bought a pump and tank seal kit from fcpeuro. I'll do the job on Thursday and hopefully I don't need the seal kit and can just return it. I'll look for cracks as well.

Dr. A8

I replaced the fuel pump yesterday but the car still won't start. I was conversing directly with Jfrahm through email and he was very helpful. It turns out that the fuel pump was not the problem. My crank sensor wiring was dangling close to the header and now it is dead. I was moving this direction when Joel said to watch for any movement on the tach while cranking. The tach is dead so that must be the problem.

I went through a lot of diagnostics on the fuel pump such as making sure the pump was getting 12 volts, checking all wiring for continuity through the connector at the top of the pump housing all the way to the pump. I jumped the pump using the battery and it ran fine. I was racking my brain trying to figure out why the pump could be jumped directly and was getting power but would produce no pressure while cranking. A search led me to the crank sensor which I pulled (thinking it was covered in metal) but it was clean. That's when Joel suggested I simply look at the tach which had not occurred to me yet.

I'm not sad that I replaced the pump as it was original and the car has 128k on it. Hopefully I have a very reliable car after all of this.

jfrahm

Well that's good news / bad news I guess, sorry we got taken in by the fuel pump symptom when it started up after you added gas. That is, if the crank sensor fixes it. It is good to get the fuel pump replaced before that leaves you walking. Good luck!

Dr. A8

Diagnosis is not always straightforward. I appreciate the help either way. I'll post when I get the sensor installed.

Dr. A8

Still struggling with this. I replaced the sensor but then had a CEL P0322 for no signal from the crank sensor. I then found that the blue wire had pulled out of the engine side of the connector. I got that fixed but am still having the same CEL. I haven't had time to trace the wires to the ECU yet but that is next.

jfrahm

If you have a DMM you should be able to see a small AC voltage from the CPS. If you have a DMM with a frequency setting you should be able to see a frequency related to the number of teeth and the cranking RPM. You can probably backprobe the connector at the ECU for this signal.

Dr. A8

I tested the new sensor and it is dead. I am returning it and getting another. I did a test while cranking and it produced no voltage.

The only other possibility I can think of is that the FUN code transmission combined with the ABZ V8 might create a spacing issue for the sensor. The old sensor when compared to the new one looks as if it might have had contact with the flex plate. I don't think so though since the car was running and now it's not.

jfrahm

Hmm. Dead is kinda surprising. This procedure sounds like it'd be appropriate for the A8:
https://www.audiworld.com/forums/aud...vance-2136877/

I thought the car was running in this configuration with the FUN trans and then pooped out a few times? The old sensor might be test-able at least, maybe if you cut off the wiring on the good side of the damage. You might also be able to test them by waving a screwdriver past the business end. I'll try this in a bit, I have a Volvo crank sensor around somewhere I plan to steal the wire off of for a 968 cam sensor repair.