1989 Ford F-150 truck wont run

Tiny
JIMPOLLARD46
  • MEMBER
  • 1989 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 84,000 MILES
My truck ran for about 7 miles then would die if I let it set it would start and depending on how long I let it set to how far I would get before it died again. I have replaced rear fuel pump, the external fuel pump, coil and plug wires, tuneup, heat sensors, oil presure sending unit, two relays on driversside firewall, distributer module, and now it will fire over when you first turn go to start it but then stops firing and wont start. HELP
PLEASE I AM AT A LOSE DONT NO WHAT IT COULD BE NOW.
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Wednesday, September 8th, 2010 AT 6:14 PM

3 Replies

Tiny
WRENCHTECH
  • EXPERT
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.
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Wednesday, September 8th, 2010 AT 6:19 PM
Tiny
JIMPOLLARD46
  • MEMBER
I did every check you ask for and they all check out good what now
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Wednesday, September 8th, 2010 AT 9:24 PM
Tiny
WRENCHTECH
  • EXPERT
No, I'm afraid that is not true. If it were, the truck would be running.
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Thursday, September 9th, 2010 AT 4:16 AM

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