I have a 2001 TT Quattro with about 53k miles. When the ambient temperatures are below 70 degrees F, the car will never start on the first try. It turns over, coughs a little, but doesn't catch. On the second try, it always starts promptly. This happens every morning except at the height of summer. I believe that this may not be the case if the car sits for over 24 hours, in which case it seems to start on the first try, but I don't have many opportunities to test that.
I have tried pumping the pedal before starting, which seemed to make a difference when it was hot, but is without effect now. I have also tried letting the car run the systems test to completion before engaging the starter motor and running the system test, turn the car off and then retry the start, all with no effect.
Remember that your new Audi has a drive by wire throttle. By, "pumping" the gas, with the key on, all you're doing is moving the throttle plate. Thats it.
Residual leak down of the fuel system would cause a problem similar to this. So next time you get in your car to start it, try turning the on, but dont start it. Wait 5 seconds, then turn it off, then start your car. Keep us posted on what happens so we can further diagnose the problem.
Thanks for the idea. I tried that as well, and it had no effect. I was testing whether the temp sensor was the issue and whether I need to let it get to the right ambient temp before starting it. Getting a new reading took about 5 seconds from key-on, but had no effect.
I'm focusing on the aberrations, because it does occasionally (1 in 20 times?) start as it should. Right now I am experimenting with letting the engine spin down for 30 seconds before turning it off. The exceptions that I am focusing on are the facts that it can sit in the parking lot at work all day (9 hrs) and start on the first try, probably can sit all weekend (60 hrs) and start on the first try but generally won't start after sitting for 12 hrs. I can't think of anything that would cause such an effect, though I am attracted by some interaction between the turbo and the fuel system, but that might tell you more about me than about cars.
I'm approaching this much like the cargo cult and will soon be walking around the car three times, singing hi-di-ho, before trying to start it.
Regrettably, I don't have a VAGCOM. I usually let it crank for about three seconds which in most cases is enough. That is always enough on the second try. Predictably, letting the car settle down for 20 seconds before turning it off made no difference.
The car is due for service in the next 500 miles and I will probably ask them to see if there are any errors associated with the fuel pump or other systems related to the problem.
Eureka. Last week I took the car in for an oil change (at a popular chain) and it suddenly had a hard time starting when warm. Nothing but the solenoid clicking. The mechanic looked at the battery, saw a lot of corrosion on the positive terminal, so we changed the battery and cleaned the cable.
Since then, one week by now, it has started on the first try every time. My best guess is that the corrosion, and maybe an old battery though it never seemed to have any problems, would not produce enough juice to run the fuel pump and the starter motor though the starter motor never sounded sluggish or labored.
Given that the car spent several days at the dealer while they were trying to fix the problem, I am somewhat dismayed that they did not discover the extensive corrosion or didn't care about it to tell me of an issue.