2000 Audi a6 quattro 4.2l v8 non-turbo. 120k miles

The vehicle died las week on the parking lot of supermarket. cranks but wont start. I had it towed home. At home I noticed the fuel pump was NOT getting power. I checked relays and then it turned on. I dont see anything physically wrong with the relay. I left it alone because I was getting power to the fuel pump now. The car would start but not stay on after 5 minutes. I would try to start and engine would not fire up. I removed back seat again and opened up the tank lid to check pump activity. If I tap on the top of fuel pump assembly with a rubber mallet, car will fire up and lacks power. I can hear the fuel pump struggling making uneven humming noises. I bought a brand new fuel pump and assembly, installed it perfectly. Car fires up every time now without faile to start. But now it wont rev up if I press the pedal. It starts misfiring. If you start the car cold...it has a horrible misfire and exploding sounds. Then after a warming a little it stays even and idle but when I press the gas it wont rev up, feels like it wants to stall after 2000 rpm. Lacks power. hesitates and misfires. I reset the computer and the same codes usually come back after 2 minutes of running engine. I did wash engine while the pump was being ordered. I did it on my drive way. but everything i can access from the engine compartment is dry. I checked mass aif flow and the plug looks dry inside. my coil packs are sealed with silicone. I sealed each one with silicone myself because this happened in the past. I also seald the around where the wire goes into harness. Just incase. any ideas?

 

It sounds like you don;t get enough fuel to both banks.

A couple of things you can check before starting to eliminate from the equation more expensive stuff:
- fuel flow after the fuel filter
- fuel flow coming into the fuel rail (fuel pressure regulator)

 

Installed new fuel filter tonight. Before installing, I flushed out the fuel lines with carb choke cleaner 4 cans. I removed fuel rail and revoved injectors from rail, sprayed each one with carb cleaner, flushed out the rail, re-installed injectors, fuel filter, etc. Everything should be clean from the pump to the injectors. Gasoline is super/ premium unleaded.
cranked the car and it does the same ****. Cold start it wont stay on. Multiple misfire. I removed mass air flow and sprayed it with carb choke cleaner, has new air filter stock. No aftermarket filters.
I started car without air flow meter plugged in and it starts fine and revs but gives me these codes, P0113, p0102, p0304. I dont think the mass air flow is bad, it was working fine! only thing I did to this ******* audi was change the fuel pump. It was running perfect and it just ******* dies! I replace fuel pump and all crazy **** starts happening! What the **** man! can't we get a break in this ******* economy? $385 fuel pump.....now this ******* peice of **** wants to give electrical problems. Who wants this car? $1000 bucks! come get it!

 

Probably you already looked at the codes:
- P0102 would be indicative of a faulty MAF
- P0113 points out to a faulty Intake Temp Sensor
- P0304 - could even be the coil
On a V8, is cyl 4 the very first one on the fuel rail, after the pressure regulator?
If you say you get these codes without the MAF plugged, then next step is probably to look into the IAT, which seems to be around $ 25. However, you got all of the other 4 cylinder misfires with the MAF connected... You can have your own conclusion.

Since the purge valve is mentioned as a possible cause, you can inspect all of the vacuum lines.
Another thing people mentioned quite a bit in relation to starting woes is the Coolant Temp Sensor, although I personally wouldn't see a relationship with the present codes...
Don't know what else to tell you, even though I want to help.
Others are surely savvyer and will point you in a better direction.
Good luck.

 

Thank you so much for your input. I get really fukin mad sometimes and start cursing at my car and cursing in the forum. I apologize for my impatience and frustrations spilling through to the forum. I was about to put a sledge hammer through the windshield and sell it for a thousand bucks and buy a xbox 360 or something. I really enjoy rebuilding the engine and transmission components. But you don't know how much I hate body work and electrical troubleshooting. I freakin hate when I can't figure out why a code/s comes up because instead of getting it right the first time....it always never fails that every freaking time I have a check engine light in any car, I start throwing money at the problem, changing this, and changing that....and after all that spending, usually figure it out at the last hair of patience. Why can't I ever get lucky and figure it out on the first shot? Never fails to figure it out in the last phase of my patience and my last dollar.

When I changed the pump, I washed the engine while the part was being shipped. It was more than a week, and engine coils had been sealed last summer by me, one by one because every time I wash engine, it misfires like crazy. I bought new iat sensor, new fuel filter, new air filter, flushed lines removed injectore to check them, try this and try that....then my buddy says to check the pugs...I say no, it's impossible that they could go bad that quick. They are fairly new, I sealed the coils water tight by applying high temp rtv silicone around the base of each coil on both sides of engine. Today I checked number 4 coil and when I lifted it out the sparkplug bore, it was wet. Water was in there! Un ******* believable. I blew it out with compressed air and the ****** car starts up normal now and revs with power and runs like a charm, no codes came up. I am still mind boggled as to why I had false codes. I would clear the codes and almost always get a different code, instead of just p0304 for that cylinder. anyway, to make a long story short, I can see this car is very sensative to water, this is the third time I had this problem. Is there a method to was engine without wetting with water?

 

Ah, ****, I was just about to ask where you live and make you the offer of the thou to buy it. Now you got the sumbitch fixed.

I could still buy an XBox and maybe make a deal with you?

Don't worry about your little bit of foul mouth. Lots of us get that way with these machines. Toyotas, they ain't.

Your mouth spat a lot more **** with your tranny problems a while back. AND then, you thought they were grand machines after you got the problem fixed, which, if you recall, was because you did not know how to FILL the ******* thing, and who in the hell would, without specific instructions?

Temperamental bastards, these machines are. They ain't made for home shop people to take care of. Go to the Audi dealer, HE knows all there is to know about them, and he won't take more than a couple weeks pay per visit.

Trouble is that most of them are shade tree mechanics working for a dealership, and no smarter than you. Parts changers, and you pay for all the parts till they finally get rid of that miss.

Cheers,

George