SloopJohnB@mac.com

with VCDS….if it doesn't start and the CPS is the problem you should see a zero cranking speed on starting.

I haven't tried this; someone else posted it. Sounds logical, but you never know.

Gruvedaddy

Just throwing out the idea of possibly a bad fuel pump. I had the same issue with a Chevy Lumina van and a Saturn SL2. Yeah, i know, they're not Audi, but a fuel pump is a fuel pump and when they get old they can start having issues. Both those vehicles would drive fine for 10 to 15 minutes or so then stall out. To rule this out possibly see if you can use a fuel pressue guage and see what the readings are. There should be a valve on the fuel rail that to connect to and get this reading as you are cranking the engine. Not sure off hand what they should be on the Audi but on my GMs they were about 35 psi. If your getting much lower numbers than what ever they should be then thats your problem. Again, just a thought. Im a novice mechanic in that i've had a lot of cars and fix them as best i can when needed. Good luck.

the_duke

I would replace CTS (coolant tempature sensor). They are cheap and is a very common failure item that doesn't always throw a code. If that doesn't work then move on to the CPS (Crank Position Sensor).

zexxe

For now the car is performing great , zero problem !
I don't know if it was the purge valve or a bad vacuum hose , but now my S is fine.
I will keep you notice if the situation will change !

Richard E. Woodward III

You all seem the most knowledgeable on this issue. MY car has just died at a light and McDonald's drive through in the last 2 weeks. First start of the morning and it's perfect. I drive 15 plus minutes and I stop and turn engine off it is a 50% chance it will start back up. The hotter the weather the worse it is.


I have replaced the Fuel Pump and fuel filter today. Drove to gas station as I was on empty and guess what it wouldn't start and after 60 minutes still wouldn't start. 90 minutes later it started right up. Temp here is 93 degrees with high humidity.


I even ordered a fuel pump relay $15.


Please explain the CTS and CPS issues and how difficult for a novice to fix? Could it be something else?

Richard E. Woodward III

What is the CPS? Cam Shaft or Crank Shaft Sensor?

LaserSVT

Crank Position Sensor. Cam sensor is usually called CAS for Cam Angle Sensor.

LaserSVT

Now while a CPS and coolant sensor are possibilities the loss of performance and the smell of fuel kinda point me towards a hung injector or a failing fuel pump. Try and get a fuel pressure gauge on it when its warm and see what the pressure is key on, engine off. Note that reading and see how fast the fuel pressure bleeds off if it takes 3-4 minutes and drops below 20-25 psi chances are you have a hung injector. If it bleeds off right away it will be a bad FPV (assuming Audis have them like every other car does) which is part of the fuel pump sending unit or a failing pump.

I am just learing my way around Audis but I do own the only 5 star rated shop in Waco and often deal with hard to start issues.

zexxe

What do you guy's think about my car ?

zexxe

Another set of photo's !