2002 Audi TT Start Problem
 

Hi there,

I have a 180HP 1.8T Quattro. I have been unable to successfully start the vehicle for the past week. I've read the forums up and down for solutions, and have been tackling each suggestion one by one.

The OBD reading shows P0171 (System Too Lean) and P0321 (Ignition/Distributor Engine Speed Input Circuit Range/Performance).

1. Fuel pump has been replaced. This was actually the original problem, as the car was not priming when the key was turned to "on". There was also no fuel at the rail. The fuel pump now makes the priming noise, so this should not be the issue. I've also checked the connection at the fuel rail to confirm it works. The car actually started and ran after replacing the fuel pump, but I have been unable to start it back up since.
2. Fuel filter replaced.
3. Fuel pump relay replaced.
4. Clean MAF sensor/(disengaged as well to see if it would help)
5. Battery replaced.
6. Engine speed sensor/Crank sensor replaced.

When I try and start the car, the car cranks and catches. It revs up to 1000 and dies 2-3 seconds later. The car is unable to hold / idle. I've even tried applying the gas pedal, but this has no effect (I would have expected the car to rev up, but it does not).

Any suggestions would be greatly appreciated, and thank you in advance.

Regards,

J

I will start checking all the vacuum lines to insured good conect

mine does this randomly sometimes, hope you fix it and tell us whats up before mine starts doin this, i will add to that I have three keys, one without the unlock lock or trunk button. its split in half. the key works to may car and turns it on but is the same for your case, it turns off.

your key sync to your car could be faulty. start with replacing your key batterey

any luck on finding the culprit to your problems...? let me know what troubleshooting you've tried if anything else has been done!!! IAT sensor clean in alcohol.. have you had the timing belt replaced recently before this?? or did you mess with any parts or sensors before this began to start happening?

Update : Solution
 

Someone had suggested to me to check the fuel pressure regulator, as perhaps the pressure at the fuel rail was low.

I googled for where the fuel pressure regulator was on the car, and I was looking at some pictures here.
The TT Gallery | The largest Audi TT Gallery on the Web, with Audi TT Pictures, Audi TT Wallpapers, etc

This image said "DON'T LOSE THIS!"
http://images6.fotki.com/v1/photos/2...SC03905-vi.jpg

I vaguely remembered pulling the clip off, and gently replacing it so I wouldn't lose it. Evidently, the piece was NOT returned to the proper location. I put it back on, and BINGO, the car starts like a champ.

Thanks for everyone's insights.

Greetings!
I am having the same problem!!!
I have not replaced the fuel pump because I have good pressure at the rail.
My battery is good, it cranks well but does not start. Just momentary fires up.
Replaced cam & crank sensors, Replaced fuel filter. Replace ECU relay.
I see you replaced the fuel pump relay; is this the same relay that I call the ECU relay?
I saw the big picture of the fuel pressure regulator retaining clip.
What finally fixed the problem for you??
Thanks
Edward