Truck quit running will not start

Tiny
MUSTANG05
  • MEMBER
  • 1990 FORD F-250
  • 7.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Was driving and truck shut off. Restarted after couple minutes. Few days later it shut off again. Has not started since. Have replaced coil, ignition mod, EEC mod, rotor, cap and even distributor. Still nothing. Help
Sunday, March 11th, 2018 AT 11:45 AM

19 Replies

Tiny
ASEMASTER6371
  • MECHANIC
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Good afternoon.

Have you checked for fuel pressure? There is an access port on the fuel rail to test the pressure. If you do not have a tester, you can rent one at a parts store.

Roy
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Sunday, March 11th, 2018 AT 12:36 PM
Tiny
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Pushed the value in and there is fuel pressure. Should I get a tester still?
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Sunday, March 11th, 2018 AT 1:03 PM
Tiny
ASEMASTER6371
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That means the pump is not working. You need to test for power to the pump.

Diagram attached. Check for power to the inertia switch first.

Roy
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Sunday, March 11th, 2018 AT 1:08 PM
Tiny
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Okay, but you can hear the pump when you turn the key on.
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Sunday, March 11th, 2018 AT 1:20 PM
Tiny
ASEMASTER6371
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Okay, good. Glad you told me that.

Then the pump has failed. It can run and produce no pressure. I would replace the pump and filter and then be sure you have fuel in the rail.

Roy
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Sunday, March 11th, 2018 AT 1:22 PM
Tiny
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Okay, even though I have pressure at the rail, and the pump runs when the key is turned on, the pump can be bad?
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Sunday, March 11th, 2018 AT 1:28 PM
Tiny
ASEMASTER6371
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There may not be enough pressure. That is why I suggested you test the actual pressure first.

Roy
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Sunday, March 11th, 2018 AT 1:30 PM
Tiny
MUSTANG05
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Okay, now we have no spark from the coil. And it is a new coil.
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Sunday, March 11th, 2018 AT 1:36 PM
Tiny
ASEMASTER6371
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Okay, get a test light and check the positive side of the coil for voltage. If you do, check the other side as well. Then crank the motor with the test light on the negative side of the coil and see if the light flashes.

Roy
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Sunday, March 11th, 2018 AT 1:38 PM
Tiny
MUSTANG05
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We have a LED test light and hard to tell. We do have the voltage.
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Sunday, March 11th, 2018 AT 1:42 PM
Tiny
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Hard to tell? Did it flash when cranking on the negative side or stay on steady?

Roy
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Sunday, March 11th, 2018 AT 1:48 PM
Tiny
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It appeared to be steady, voltage dropped.
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Sunday, March 11th, 2018 AT 1:49 PM
Tiny
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Voltage dropped?

If it is not flashing the module is not working. You either have a bad module or distributor pick up coil in the distributor.

To check the pick up coil, disconnect the connector and test the ohm reading on the coil. It should be 800-1100 ohms.

Roy
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Sunday, March 11th, 2018 AT 2:03 PM
Tiny
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Coil, ignition module and distributor all new. Replaced yesterday.
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Sunday, March 11th, 2018 AT 2:07 PM
Tiny
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Okay, still need to check it. It is possible to get bad new parts.

Roy
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Sunday, March 11th, 2018 AT 2:08 PM
Tiny
MUSTANG05
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Could it be the PCM? Anyway to check that?
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Sunday, March 11th, 2018 AT 2:30 PM
Tiny
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Not likely at all.

You need to check the pick up coil as I suggested and then the module. Take the module to the parts store and they can load test it to see if it is working.

Roy
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Sunday, March 11th, 2018 AT 2:47 PM
Tiny
MUSTANG05
  • MEMBER
  • 10 POSTS
  • 1990 FORD F-250
  • 7.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Have changed almost everything in the ignition. Nothing. Email jdthomas56@comcast. Net
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Tuesday, March 13th, 2018 AT 6:19 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,279 POSTS
Hello,

Does the engine have compression? Here is a guide to help us get started:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

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Tuesday, March 13th, 2018 AT 6:19 PM (Merged)

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