werick

Im having a issue with the audi i just bought it takes more then five times of cranking to start the starter sounds good and seems like it isnt getting fuel. When it starts runs fine but also i cannot get my scanner to read any codes even though the air bag light is on and the car doesnt start automatically. what could be my possible problems?

tenspeed

Short answer is that it could be a weak battery or the fuel pressure regulator leaks down overnight or the fuel pump isn't sending as much pressure as it did when new. Might by a combo platter of all three.

I would guess that it starts ok after the engine is warmed up. If you can, try letting the fuel pump fully pressurize the fuel rail before turning the engine over. IDK if it's possible with the A6C6. I do it on my non-Audi by turning the ignition on until the fuel pump shuts off. I'll do it a couple of times if it's really cold or if the car a sat a few days.

The ECU is in open loop at start up and it sends a rich mixture to the cylinders. It goes into closed loop after a half minute, the O2 sensors are in the circuit and the ECU meters the amount of fuel needed. If the fuel pressure is low at start up, it will take a few more turns to get it to fire.

The A6C6 might be totally different - I'm going on observations and experience from working on other cars. Good luck and I hope it helps.

Wake96c4

My A6 had a similar problem when I first purchased it in September, the dealer fixed me up.

It would start then immediately die, then I'd have to crank the engine for quite a few seconds on the second attempt to get it running and it would run poorly for the first 10 or so seconds.

They told me that the fuel pressure regulator is built into the fuel filter, they simply changed the fuel filter for me and I haven't had a problem with problem starts since.

KevinGary

You may also want to consider this TSB

http://uberlame.com/a6_tsb/Engine/En...ong%20Time.pdf

werick

Ive read about the frv on another forum chances are that could be the problem hoping to get it fixed asap and will let yous know....

werick

Jus changed out fuel press reg vavle and still nothing it sounds like it wants to crank over but isnt cranking over at all now... it is also snowing and it seems to start better when it is warm outside any ideas??

newa6er

did you change the fuel filter? You should really have somebody check the fuel pressure at the rail. For a cheap fix that may or may not help, I would buy 2 bottles of Techtron fuel system cleaner and run that through with a full tank of gas. Make sure you are using the highest test gas.

Does it start right away after it's warm?

werick

Well the guy i bought it from said when he changed out the fuel pump with another from one of his cars he said it started... so i am going off that im sure that he knew the fuel pump he did put in was having issues but didnt mention especiallu cause he said he was a mechanic but its a issue i plan to figure out by buying a new fuel pump i would try to do the fuel pressure test but the tools are at my school we still on vaca plus the cars batt went dead from me tryna crank it so many times before and after i replaced the FPRV... i get the part on tuesday and will kepp a post to let all know if it was a fix.. im just hoping ita not the plugs n wires or coils that will just b more to fix for a car the supposably worked great the day before i got it lesson learned but will b a great car when its running i have no doubt

werick

So i put in the pump today and it starts but wont stay started... could i have possibly connected the two wiring harnesses that go to the top of the fuel pump wrong?? Or is it something else??

werick

Ight have replaced pump, fpr, made sure there was fuel pressure but havent checked the relay and still having these issues leads me to believe its a vac leak in the main air supply it even makes a unneccessary noise.. does anyone have a clue what im talking about and can help out