1981 Ford F150 warm engine start

1981 FORD F-150
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HIGHLINER1
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Engine Mechanical problem
1981 Ford F150 V8 Four Wheel Drive Automatic

Our truck will not re-start when warm, unless it sits and cools for 30 minutes or so. It has trouble turning over. We have replaced starter & wraped exhaust thinking starter over heated. Also have replaced battery & all connections. Has anyone else had this problem? We are not sure where to go next? thanks, Mark
Mar 28, 2010 at 10:40 AM
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RASMATAZ
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Hi highliner1, Welcome to 2carpros and TY for the donation

Our truck will not re-start when warm, unless it sits and cools for 30 minutes or so. Don't wait for nothing do below immediately

Pick your symptom below and perform the checks and get back with me asap with some testing results

Cranks but no start condition:

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine at least 3/16 away from ground -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it.

If both fuel and spark is present-check the valve and ignition timing, this will lead you to problems
with compression and valves opening and closing at the wrong time/broken or jumped timing
belt/chain.

No crank at all/nothing/nada:

Could be the starter, starter relay, park and neutral switch/clutch switch and ignition switch assuming the battery and connections are good
Mar 29, 2010 at 6:58 AM
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HIGHLINER1
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I want to be more clear, the engine has trouble turning over when warm. We thought it was the battery & or connections at first because with a good charger "boost" it would barely turn over & start. But wait a few minutes and it cranks right over and starts fine. Do I still check everything you thought or does this make a difference? Thanks
Mar 29, 2010 at 7:32 AM
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RASMATAZ
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Use a remote start or short out the starter relay and check if it still cranks the engine over slow-we start here.
Mar 30, 2010 at 6:00 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.