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Possible PCM issue

Tiny
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  • 1996 FORD F-250
  • 7.5L
  • V8
  • 4WD
  • MANUAL
  • 230,000 MILES
Sometime doesn't start first time, but has started eventually. Sometime engine quit's while driving, does start when it want's eventually. ABS light comes on and goes out randomly.
Saturday, March 7th, 2020 AT 12:01 PM

24 Replies

Tiny
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Good afternoon.

The ABS has a fault code stored for the anti-lock system. I need those codes to further help with that issue. A parts store will read it for free.

https://www.2carpros.com/articles/abs-warning-light-on-easy-repair-guide

The engine could be low fuel pressure. I would check the actual pressure before assuming anything.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Is the check engine light on with codes?

Roy
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Saturday, March 7th, 2020 AT 1:17 PM
Tiny
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No codes on check engine light, truck runs awesome when it's running, after it shut off, and started back up. I drove it home approximately 25,000, no problem's.I just ran the truck for about 15 minutes with no ABS light coming on, very intermittent.
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Saturday, March 7th, 2020 AT 2:13 PM
Tiny
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Okay, the ABS still has stored faults. I need those faults.

Did you check the fuel pressure as I suggested?

Roy
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Saturday, March 7th, 2020 AT 2:16 PM
Tiny
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Just checked fuel pressure on fuel rail. I think it's low as you suspected, does not spray fuel it just kinda runs out.
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Saturday, March 7th, 2020 AT 2:39 PM
Tiny
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There you go. Good find.

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy
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Saturday, March 7th, 2020 AT 2:54 PM
Tiny
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Hey Roy, changed fuel filter, lot's more pressure. Took it for a drive two k down the road the ABS light came on. Checked fuel pressure seem's like not as much fuel volume. Raining too hard to continue trouble shooting, Doesn't make a difference which tank I use. Any ideas?
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Saturday, March 7th, 2020 AT 6:23 PM
Tiny
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Check the actual pressure. You will need a gauge.

Again, I need the ABS fault code for that.

Roy
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Sunday, March 8th, 2020 AT 1:19 AM
Tiny
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I think the problem is electrical. I originally thought it was the ICM, but when it died I put on my spare ICM, didn't make a difference, still didn't start. When it did start I tried the other ICM and it started also. Like there was no power getting to the ICM.
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Monday, March 9th, 2020 AT 11:47 AM
Tiny
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Me again.I did a pressure test, fuel pressure is around book spec's. I took it for a short drive last night, it shut off but started right back up. It was fine the rest of the way home. Any other ideas?
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Monday, March 9th, 2020 AT 7:32 PM
Tiny
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Okay. What was the exact pressure?

Roy
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Tuesday, March 10th, 2020 AT 2:54 AM
Tiny
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32 psi, when truck is running.
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Tuesday, March 10th, 2020 AT 3:06 AM
Tiny
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35-40 pounds is the spec for the pressure.

I think you need a fuel pump.

Roy
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Tuesday, March 10th, 2020 AT 3:08 AM
Tiny
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Both tank's have a fuel pump. Same pressure reading in both tank's. Seem's to be more of a ignition problem. Truck does not sputter or starve for fuel, it's more like i'm turning the key off. Wondering what would cause the ICM to not have power to it?
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Tuesday, March 10th, 2020 AT 11:40 AM
Tiny
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It could be the module or the distributor pick up if it is ignition related.

I would not blow off the pressure so quickly.

How did you verify you have no power to the module?

Roy
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Tuesday, March 10th, 2020 AT 1:39 PM
Tiny
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To reword things; it'snot the ICM, one time when it shut off I changed the ICM with a good working ICM, still didn't start. This problem has been doing this intermittently for 4 years. I'm not sure if it's possibly the hall effect or maybe a short in the coil or maybe the power-train control module. Sometimes it will go for hundred's of kilometer's without any problem's.
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Tuesday, March 10th, 2020 AT 5:20 PM
Tiny
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When it does not start, do you have spark and fuel pressure?

Roy
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Tuesday, March 10th, 2020 AT 5:28 PM
Tiny
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I have no idea, I'm usually in the middle of the road or intersection. I'm just trying to get it to start and get off the road. The last time it shut off it took a couple of minutes before it started. I moved about 100 feet and shut off again, took about 5 minutes before it started again. Then it ran good all the way home approximately 25 kilometers.
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Tuesday, March 10th, 2020 AT 7:37 PM
Tiny
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That is the time you need to check it for the spark and fuel.

Roy
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Tuesday, March 10th, 2020 AT 8:08 PM
Tiny
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Supposing there is no spark. What's the diagnosis Doc?
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Tuesday, March 10th, 2020 AT 8:28 PM
Tiny
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You will need a test light and test for power on the negative side of the coil. There should be power. Then crank the engine. The test light should flash while cranking.

If it is flashing and you have no spark, you need a coil. If it does not flash, you need an ignition module.

Roy
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Wednesday, March 11th, 2020 AT 2:43 AM

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