1987 Ford F-150 No spark when hot

Tiny
FARMACIST
  • MEMBER
  • 1987 FORD F-150
  • 6 CYL
  • 2WD
  • MANUAL
  • 239,000 MILES
My pickup runs great when cold, however when it gets hot (operating temperature) if it stalls it wont restart for 10 minutes or so until it has time to cool off. I have replaced the ignition coil and tfi module, several relays (various ones just trying to narrow a few things down). Just by chance I discovered if you disconect the timing sprout it will restart. Any ideas?
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Wednesday, September 24th, 2008 AT 6:55 PM

5 Replies

Tiny
BLACKOP555
  • EXPERT
Hmm, sounds like it could be a badhall effect sensor.

Its like a pickup coil only thing is ford switched to the hall effects in 87.

Check that first. If it feels like tar it is definetely bad.
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Wednesday, September 24th, 2008 AT 7:04 PM
Tiny
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Well I have been at work for the past few days but did get your reply. One day at lunch I stopped by the parts store and found out I could get a new distributor for $100, not bad. Comes with the PIP sensor and a new TFI module, so I sprung for that (figured I may as well change it all just in case!). After work last night I came home droped it in and went for a drive. Still doesnt restart when hot. Its a real head scratcher. I bought the truck cheap, as it had this problem when I got it. But I thought I could fix it. That was 2 years ago
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Sunday, September 28th, 2008 AT 6:46 AM
Tiny
BLACKOP555
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I think there may be a issue with the computer tryign to overadvance, and the hot engien will never start you can try to retard the timing manually a few degrees that way it wont advance so much when hot, does this help?

By disconnecting the spout the computer reverts to base timing and starts.
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Sunday, September 28th, 2008 AT 7:58 PM
Tiny
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Sorry it has been a while, things have been crazy in my neck of the woods! I tried the timing trick, with no luck really. I have a pretty heavy relay, I think I might put that in line with the timing spout, while getting power from the coil (so that the spout is disconected while cranking the starter). I know its not the right way to fix it but it may work for a while!

It does run alot better with the new distributor and all!
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Tuesday, October 28th, 2008 AT 5:27 PM
Tiny
BLACKOP555
  • EXPERT
Bypassing the spout when cranking helps the engine start better? Have you checked your igniiton timing?

Make sure your hall effect sensor and the metal trigger wheel is properly set with eachother.
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Tuesday, October 28th, 2008 AT 7:43 PM

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