Ottoman56

Hello all. I have a 2001 allroad 2.7t. When I drive the car long enough to get it up to normal temperature, when I turn it off, after about an hour it won't start again. When it completely cools off it will start again. I am stumped. I tried a coolant temp sensor, fuel pump, fuel pump relay. No luck. I have figured out that when the car does not start, it cranks but does not seem like it is getting gas. I took the rear seat out when I changed the fuel pump. When it does not start I do not hear any noise from the fuel pump. Then when the car cools off and I try it again, then I can clearly hear the fuel pump working.
Any help would be greatly appreciated.

amiram

If you have the option check for fault codes

Ottoman56

The only code is p0491. That is the secondary air system fault. I replaced the secondary air pump and the fuse. When the car is cold I hear the pump run. What is interesting is that I disconnected the battery and just yesterday the check engine light came back on. It is still the p0491 code?

amiram

You must delete the fault code, disconnecting the battery does not erase the code.
In this forum has a number of trades that are dealing with "engine not start" You'll find the answer there.

Ottoman56

I have looked through every forum that talks about engine not starting. I have replaced every part that I have read might be the cause. Throwing parts at this car is getting expensive. I was hoping for a new idea as to what my problem might be. It seems to me to be a pretty particular case. What makes a car not start an hour and a half after you shut it off? Then, give it another hour and it starts right up? I have not seen that in a forum any where.

Kneale Brownson

Google Audi Allroad engine speed sensor.

Ottoman56

Turns out it was the Anti theft module in the key.

audi-1norway

try to ckek the camskaft sensor, it has build in a security to prevent engine damage, in another car of my friend he changed the knocking senor on the camshaft and that resolved his issue

dexter.mac130@gmail.com

How did you diagnose and fix this?

I suspect mine is doing the same, as I recall the guy I bought the car from mentioned something about it.