1g starting troubleshooting help

[Kolat]

This thread may be a little advanced for the newbie forum, but starting issues.

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car: 92 TSI AWD Auto

Issue: Fails to crank over when it's warm. Starts instantly once cooled down.

Top end of engine was re-built by a shop for previous owner, shop was a bunch of hacks, but thats another ball of problems.

Currently if I drive the car for any longish period of time (>30 min) then when I go to start the car is sometimes fails to turn over. I can hear the fuel pump relay click in the back, and hear a relay click in the ecu area. Moving the gear selector around does'nt change the results. My last 5 dsm's have been 5-speeds so I don't really know the order of operations for troubleshooting an auto is as far as the gear selector switch etc. The possible causes that I can come up with are.

Starter relay
gear indicator sensor?
Coolant temp sensor
Ecu caps?

Anyone got any thoughts on this? I have a few spare sets of caps around but I really despise doing the caps on my winter driver during the winter. I can't remember for the life of me if the coolant temp sensor failing causes the car to not turn over or if it just drops injector pulsewidth to 0, I think it drops the injectors but memory is fuzzy.

T

 

[doubleclutch99]

check to make sure the grounds are all tight on the battery and the engine. and there's always the possibility you're getting heat soak in the starter.

 

[SLOWMARO]

i have seen a start lock up when it got hot, had to tap it with a hammer to get it to turn over