92 silo won't start when hot

[dubbster59]

3.8, 216,000 miles, replaced the coil packs 80,000 ago, replaced ignition control module 3X, replaced the overheated wiring harness from the ICM, new fuel pump and filter, starts well when cold, runs 15-20 min then I turn it off and won't restart. takes 2 hours to overnight to cools and starts right up.

anybody have any ideas? sure would like to figure this out.

[Tech II]

Do you have spark or injector pulse when it won't start? If no, and you ICM is ok, would be leaning towards the crank sensor behind the harmonic balancer...

[dubbster59]

No spark at the coil packs, havn't checked the injector pulse but the crankshaft sensor is next on the list...I just know it is a bear to get at!
Would that crank sensor be heat sensitive? I have replaced the wiring harness up to that sensor where it got roasted so the the wires are good (ohms check) What about the cam sensor? do they go bad to?

Thanks!

[Jrs3800]

I would lean towards the Crank sensor...

You could run without the cam sensor, may not run 100% but it will start and run...

On the Crank sensor, yes they can be come heat sensitive... some will just stall out and restart, others will stall out and not restart until cold...

The next time it stalls and you have no injector pulse, replace the crank sensor... Also being a 92 you will need to set the sensor to the proper location..

[dubbster59]

Thanks to all who responded, Changed out the crankshaft postion sensor last night and that did it...starts right away runs well and hasn't shut down in about 20 start cycles. Instructions on the CPS call out a feeler gauge check of.020 but I couldn't figure out how to even get one in there behind the harmonic balancer....
Sooooooooooo after considrable thought, I folded up some regular bond paper in half, cut it to about a 1/2" strip and fitted it into the gaps of the sensor which allowed the rings of the harmonic balancer to fir snugly into it. Loosely fasten the CPS to the block, start the HB onto the crank while ensuring all the teeth line up well. tighten the HB onto the crank, tighten the CPS, turn the HB 1/8 turn, pull out the paper and your done! simple fix for complicated "how do I gauge this?"

Have a great Day!

Dubbster