Hot start-wont start

[Kenneth Keith]

"James Miller" <threadlessclimber at hotmail.com>
>
> Hello,
>
> I'm having issues with the car starting once it is warm.
> this is what is happening
> 1.the car starts fine after sitting since the day before
> 2. I drive 5 miles and stop and eat lunch
> 3. when I return after 45 min. the car didn't start on the first try but
> fired up on the second try (it was about 80 degrees and the car was in the
> sun)
> 4. I then stop next door to get gas and it wont start--the starter cranks
> and the engine almost catches but then dies.
> 5. with the car rolling-I pop the clutch and it hesitantly started
> 6. I then drove 15 miles and parked it in the shade. I tried to start it
> initially after parking it and it wouldn't go.
> 7. The car sat for more then an hour in the shade and started right up on
> the first try.
> 8. The car started with no problems this morning.
> 9. Then I stopped and parked in the sun at the bank after the car had been
> running for a 1/2 hour or so and it wont start. It's in a busy parking lot
> with little room so it is still sitting there. I plan to go back in a few
> hours when the engine has had time to cool down completely
>
> A few years back the idle stabilizer valve was replaced--when that went it
> would catch but wouldn't stay at idle--this time the idle doesn't catch. A
> year and a 1/2 ago the starter brushes where dirty and it had trouble
> starting but after a little cleaning I've had no problems.
>
> The car recently had a brass distributor gear installed. Could something
> have happened then? Am I silly to think that it might have something to do
> with sitting in the direct sun light?
>
> I'm not in a position to do much until I get it home and so I put this out
> to the Audi minds--to get it off my mind as I wait in bewilder anticipation.
>
> Thanks for time,
> James Miller
> 91 200 tqa

The timing wheel sensors can go out and it is a heat-related failure.
If you have access to another one to test, swap in a different sensor
for counting flywheel teeth and see if that helps.  You may be able to
learn something by swapping the sensors in their locations, since the
other sensor only has to work some of the time.  If the ecu doesn't
detect the engine turning, then it won't activate the fuel pump.

I never heard of this failure until friend's 200q10v had it, and
another guy immediately said that's what it was, and it was.  This car
would run find until it got hot and then start dying like it had vapor
lock or a fault fuel pump.  It wouldn't restart until it cooled off.
Another used sensor fixed it.

Ken