Help!
Tuned
Joined: Jan 2021
Posts: 377
Likes: 81
Again, have you tried starter fluid in the intake? Yes, be careful, but if it is not kicking over with that, then fuel is NOT your problem.
Tuned
Joined: Jan 2021
Posts: 377
Likes: 81
I completely disagree with your statement. Why would resetting the power to the computer cause it to run continuously when you cycle the key from the Off to Run position?
That function is hard coded in the computer. No amount of power cycling or clearing codes is ever going to change the hard coding.
That function is hard coded in the computer. No amount of power cycling or clearing codes is ever going to change the hard coding.
https://eectuning.org/forums/viewtopic.php?t=6379
That being said, I am on board with the strong possibility of it being a BAD PCM.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Everything I have read indicates it is hard coded on the computers in these trucks, which does not make me 100% correct. I have never seen any amount of power cycling, clearing memory, etc. cause this issue on this vintage truck. This issue has happened numerous times on this forum and it has turned out to be a bad computer. The qualifier here is there was no other rigging like hard wiring the fuel pump relay, hot wiring the fuel pump, etc. In those cases obviously the computer is not at fault.
In this scenario we can agree that the most likely culprit of the OP's issue is computer related unless they come back stating there was some other wiring changes made.
Yes I have cleared the KAM on several of my OBS trucks, 1992 F350 5.8L gas engine and two 1993 Lightnings, and never experienced a continuously running fuel pump afterwards. Reading through that procedure you linked to they are removing the KAM power which may be what is killing the clock signal, but the main EEC power is still on, so that is why the fuel pump kicks on?
In this scenario we can agree that the most likely culprit of the OP's issue is computer related unless they come back stating there was some other wiring changes made.
Yes I have cleared the KAM on several of my OBS trucks, 1992 F350 5.8L gas engine and two 1993 Lightnings, and never experienced a continuously running fuel pump afterwards. Reading through that procedure you linked to they are removing the KAM power which may be what is killing the clock signal, but the main EEC power is still on, so that is why the fuel pump kicks on?
Tuned
Joined: Jan 2021
Posts: 377
Likes: 81
Everything I have read indicates it is hard coded on the computers in these trucks. I have never seen any amount of power cycling, clearing memory, etc. cause this issue on this vintage truck. This issue has happened numerous times on this forum and it has turned out to be a bad computer. The qualifier here is there was no other rigging like hard wiring the fuel pump relay, hot wiring the fuel pump, etc. In those cases obviously the computer is not at fault.
In this scenario we can agree that the most likely culprit of the OP's issue is computer related unless they come back stating there was some other wiring changes made.
Yes I have cleared the KAM on several of my OBS trucks, 1992 F350 5.8L gas engine and two 1993 Lightnings, and never experienced a continuously running fuel pump afterwards. Reading through that procedure you linked to they are removing the KAM power which may be what is killing the clock signal, but the main EEC power is still on, so that is why the fuel pump kicks on?
In this scenario we can agree that the most likely culprit of the OP's issue is computer related unless they come back stating there was some other wiring changes made.
Yes I have cleared the KAM on several of my OBS trucks, 1992 F350 5.8L gas engine and two 1993 Lightnings, and never experienced a continuously running fuel pump afterwards. Reading through that procedure you linked to they are removing the KAM power which may be what is killing the clock signal, but the main EEC power is still on, so that is why the fuel pump kicks on?
Lets see what his next move is.
FWIW, By using Binary Editor and a Quarter Horse chip, using the KAM clear procedure, The pumps will stay on, but only until the motor is started. So I do not believe that to be the issue. KAM can also be cleared if you disconnect the harness at the PCM, but this issue has been there prior to him doing that.
Thread Starter
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New User
Joined: Jan 2022
Posts: 14
Likes: 0
Computer
Agreed, it truly does seem to be the EEC is jacked. He is either not getting spark, or the injectors are not firing. If no spark then it could be the ICM, some carb cleaner or other starter fluid would eliminate that.
Lets see what his next move is.
FWIW, By using Binary Editor and a Quarter Horse chip, using the KAM clear procedure, The pumps will stay on, but only until the motor is started. So I do not believe that to be the issue. KAM can also be cleared if you disconnect the harness at the PCM, but this issue has been there prior to him doing that.
Lets see what his next move is.
FWIW, By using Binary Editor and a Quarter Horse chip, using the KAM clear procedure, The pumps will stay on, but only until the motor is started. So I do not believe that to be the issue. KAM can also be cleared if you disconnect the harness at the PCM, but this issue has been there prior to him doing that.
Lead Driver
Joined: Jan 2019
Posts: 5,081
Likes: 865
From: N.W. Alabama
Boy you really give the least amount of info, possible, to need help getting it fixed, Have you tried starter fluid sprayed into intake track, and did it start up, when you did, or have you verified your getting spark?
what truck, motor, trans, did it have.
what truck, motor, trans, did it have.
Laughing Gas
Joined: Oct 2018
Posts: 1,009
Likes: 86
From: San Diego
Put the computer from an 88 in.
What have you got to lose at this point?
How much is a new computer at a reputable auto parts supplier?
What have you got to lose at this point?
How much is a new computer at a reputable auto parts supplier?
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Hotshot
Joined: Jun 2015
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Likes: 2,445
You haven’t answered any of the questions that have been asked: do you know there is spark? Actual fuel pressure vs presence of fuel at the rail. Now you want to replace the computer with one from an ‘88 but from what I saw we don’t know what engine/trans combination is in your ‘87 or what engine/trans combination is in the ‘88. so it many or may not be better than what you have. All the gas engines were EFI in ‘88 so are you trying to put a 460 computer in a 300 powered truck or the other way around?
Tuned
Joined: Jan 2021
Posts: 377
Likes: 81
You really need to understand, that this not just a point and shoot fix it. There could be several things that are causing your truck to not start. It's called troubleshooting, not shotgunning.
We are asking questions for a reason, and you are not answering them. You need to figure out what the cause(s) is/are. It could be one simple thing, or multiple different things.
About the only thing we really know is you have a 1987 truck, we have no other info on it other than it ran when you started working on it, and now it doesn't.
As asked above, Motor size? Trans?
Have you tried priming the motor with starter fluid? Spray a small amount directly in the intake and crank it. Does it turn over?
How much pressure do you have at the fuel rail, there are several write ups on how to test that, but you will need a gauge, Not that expensive.
Let's start with this and then we can move forward.
We are asking questions for a reason, and you are not answering them. You need to figure out what the cause(s) is/are. It could be one simple thing, or multiple different things.
About the only thing we really know is you have a 1987 truck, we have no other info on it other than it ran when you started working on it, and now it doesn't.
As asked above, Motor size? Trans?
Have you tried priming the motor with starter fluid? Spray a small amount directly in the intake and crank it. Does it turn over?
How much pressure do you have at the fuel rail, there are several write ups on how to test that, but you will need a gauge, Not that expensive.
Let's start with this and then we can move forward.
FTE Chapter Leader
Joined: May 2006
Posts: 12,342
Likes: 1,315
From: Central Mississippi
I've seen pile-ups on I-20 less painful... 
To the OP, newbie help-mates & anybody else:
1) These trucks have been in service 25, 30 years. There are things Ford expected them to do & things that they didn't.
2) The biggest catalog of tens of thousands of faults in several millions of trucks are here in the posts of this forum & in the minds of those who have participated the longest, not all, but quite a few.
3) When you get a clear "when this happens, it is this", particularly from some one who's been here a decade or 2, & speaks with the actual technical knowledge, you need to put obstinacy aside & get on with the repair.
YRMV
To the OP, newbie help-mates & anybody else:
1) These trucks have been in service 25, 30 years. There are things Ford expected them to do & things that they didn't.
2) The biggest catalog of tens of thousands of faults in several millions of trucks are here in the posts of this forum & in the minds of those who have participated the longest, not all, but quite a few.
3) When you get a clear "when this happens, it is this", particularly from some one who's been here a decade or 2, & speaks with the actual technical knowledge, you need to put obstinacy aside & get on with the repair.
YRMV
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