Hi guys,

I just bought a 2001 S4 with only 80,000 km mileage.
Mechanically is fine.
Just changed the timing belt several hundreds kilometers ago.
Changed the old plugs, but still have to replace the airfilter.

I have some problem with my new ride.
The engine is difficult to start after leaving the car for a while.
At the beginning, it didn't happen all the time.
In the morning when starting the car to go to work and in the afternoon when going home from work.
However, this become worst.
Today, I can't start it at all.

If you would start the car when the engine is still warm, no problem at all.

I would start the engine till the oil sign at the matrix would lit up.
The start motor is cranking the engine.
Smell some petrol.
But the car won't start.
I even tried to start while pushing the accelerator.

Then I did some searching and tried several actions:
- Cleaned de MAF
- Alligned the throttle body

No result.

I would appreciate it if someone has the same experience and is able to help me out.

Many thanks in advance.

 

what kind of plugs did you end up putting in? could be a gap issue? could also be fuel management, does your car surge when you step on the throttle? air, or water in the lines.... million things i suppose. vag it, see if it throws some codes.

 

Tx for the reply.
Don't have time and equipment to do the investigation.
Will have it connect to the computer and will post the codes.

Man, I wish you could use the old fashioned trouble shooting.
Too many electronics nowadays.

The strange thing was: this morning I gave it a try after the start failure yesterday.
I started the engine without applying any throttle.
=> The engine starts after 2 cranks!!!

 

So on a cold start does it fire right away or not?

Sounds to me like it could be a coolant temp sensor(if the car doesn't fire in the am) or possible crank position sensor (if it doesn't fire once car is warm and car is shut off).

What are the codes you have?

 

Hi. I had similar problems. I changed the coolant temp sensor. That fixed the prob.

When you start the engine while its cold, it will need more gasoline. When the engine is warm it needs less gasoline. So when the cts doesn´t work the ecu believes that the engine is cold all the time, so when you wanna do a warmstart the ecu injects too much gasoline for a start. Its flooded.

Good luck.

 

We discussed this problem on s4forum.com.
Maybe this can help you
http://s4forum.com/forums/showthread...ight=warmstart

 

I managed to get the car behind a computer.
2 error codes were shown:
- Oxygen sensor.
- Cam sensor.

Both are cleaned and we'll be waiting for the result tomorrow morning.

The problem I have with the car is a cold start.
After the engine is warm, no problem at all to start it.

Will provide the update the next time.

 

Got the car back with no errors indicated by the computer.
Still, once in a while the car still has difficulties to start.

Hi Crank,

Tx a lot for the advice.
I will replace the CTS as well then.
According to the diagnostic computer, the temp reading is too high.

More update will follow.