PCM swap

Tiny
JAMESBURROW
  • MEMBER
  • 1998 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 377,000 MILES
Will a power control module (PCM) computer out of a 2001 ford F150 5.4l work in my truck listed above as long as I take it to the ford dealership and have it reprogrammed?
Do you
have the same problem?
Yes
No
Monday, July 27th, 2020 AT 7:31 AM

44 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning,

It must be the exact number of the one you are replacing and you have about a 50-50 chance of it taking the program. Sometimes it works fine and other times it does not.

Roy
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Monday, July 27th, 2020 AT 7:56 AM
Tiny
BMDOUBLE
  • EXPERT
It used to work with previous program levels of the diagnostic software, but the last time that I tried doing a PCM swap it didn't work, but some techs keep their own laptops with older versions that might work.
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Monday, July 27th, 2020 AT 8:00 AM
Tiny
JAMESBURROW
  • MEMBER
What would you recommend I do?
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Monday, July 27th, 2020 AT 8:06 AM
Tiny
ASEMASTER6371
  • EXPERT
If you need an ECM, I would get a new one and have it flashed to your VIN.

What makes you think you need an ECM?

Roy
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Monday, July 27th, 2020 AT 8:21 AM
Tiny
JAMESBURROW
  • MEMBER
Because when I got the truck the idle would go up and down randomly and I would be driving it and all the sudden it would lose power and then kick back in randomly. Then a couple of months later one day it started running rough and it didn't have any power at all a week. After that I was going down the road and the truck shut off and wouldn't start back up. It would turn over but not even try to start. I plug a code scanner up to it and it just says error. The day after it broke down the battery was dead and it was a new battery. Oh, and it seemed like it took a long time to shift gears.
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Monday, July 27th, 2020 AT 9:13 AM
Tiny
ASEMASTER6371
  • EXPERT
Tiny
JAMESBURROW
  • MEMBER
No, it will turn over but wont even try to start.
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Monday, July 27th, 2020 AT 12:47 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, you need fuel pressure, spark and compression.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Can you hear the fuel pump run with the key on?

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

When you crank the engine, does it show RPM on the tachometer on the dash? That will tell me if the crank sensor is working.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Compression would be last.

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

Roy
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Monday, July 27th, 2020 AT 12:55 PM
Tiny
JAMESBURROW
  • MEMBER
No, the rpm doesn't move at all. When I turn the key on I hear 2 clicks under the dash it sounds like something is trying to turn on but then it turns back off.
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Monday, July 27th, 2020 AT 12:59 PM
Tiny
JAMESBURROW
  • MEMBER
And no I don't hear the fuel pump come on when I turn the key on. I have already changed the fuel pump and filter, because I thought it was going out.
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Monday, July 27th, 2020 AT 1:01 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, we need to do some testing. Do you have a voltmeter and a test light?

https://www.2carpros.com/articles/how-to-check-wiring

We need to check some powers at the power relay and the fuel pump relay.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Roy
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Monday, July 27th, 2020 AT 1:18 PM
Tiny
JAMESBURROW
  • MEMBER
Yes sir, I have both a voltmeter and a test light, but i'm at work right now I get off at 5:00 so I will be home around 6:30. Can we continue this diagnostic test when I get home?
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Monday, July 27th, 2020 AT 1:37 PM
Tiny
ASEMASTER6371
  • EXPERT
Tonight will be fine.

Roy
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Monday, July 27th, 2020 AT 1:41 PM
Tiny
JAMESBURROW
  • MEMBER
Okay, thank you so much. You don't know how much I appreciate this.
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Monday, July 27th, 2020 AT 1:42 PM
Tiny
BMDOUBLE
  • EXPERT
Pop the hood and on the driver side, open the fuse box cover and give this relay a tap. If it starts or stalls when you tap it, try swapping it with it's neighbor. Very very very common!
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Monday, July 27th, 2020 AT 2:30 PM
Tiny
ASEMASTER6371
  • EXPERT
As he said, that is the power relay that controls all power to the fuel pump relay and a lot of other components that I highlighted in the diagrams I sent you.

Roy
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Monday, July 27th, 2020 AT 3:12 PM
Tiny
JAMESBURROW
  • MEMBER
Okay, so I checked all my fuses and I found a couple of them that were blown so I replaced them and my truck started and stayed running but it still has no power. It idles when I have it in park just fine but once I put it in gear it it idles real low and tries to shut off. When i'm driving the engine runs rough like it has a couple of cylinders misfiring and when I give it gas it acts like it has a vacuum leak. I have to barely touch the gas pedal little by little and let it build up speed it takes me about 1 1/2 miles to get up to 35 mph.
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Wednesday, July 29th, 2020 AT 4:28 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, you need to go back to my original suggestions and check the fuel pressure. That is the start.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

https://www.2carpros.com/articles/engine-has-low-power-output

I also suspect the exhaust is clogged from cat converters. You could get a back pressure gauge or you could loosen the head pipes from the manifolds and then drive the truck and see if power returns.

Roy

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Wednesday, July 29th, 2020 AT 4:39 AM
Tiny
JAMESBURROW
  • MEMBER
It's not the catalytic converters. I got some off another truck and swap them out and still the same problem. I found a plug towards the back of the motor on top that is not plugged into anything not sure what it's for. I was wondering if maybe you knew.
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Wednesday, July 29th, 2020 AT 7:56 AM
Tiny
ASEMASTER6371
  • EXPERT
Can you post a picture for me of the plug?

Also, did you check the compression in a cylinder or 2 to see if the valve timing jumped?

I would not rule out the exhaust. I would drop the front pipes and start it and drive to be sure the rest of the system is not restricted.

Roy
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Wednesday, July 29th, 2020 AT 8:58 AM

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