pin 4
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pin 4
i have a 94 150 4.9 liter six cylinder with the tfi ignition. For some reason I am not getting the required amount of voltage on pin 4 PCM to remote mounted ICM. I have about 2 volts when i need 90% of battery. I have continuity between the two. I have also replaced both PCM and ICM. I have used a scanner and the system is fine.
Fleet Owner
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From: Kentucky
Pin 4 is supplied battery voltage through fuse U in the engine compartment fuse panel. That supply is also the "battery" side of the coil. Pull the fuse measure the resistance between them, it should be very close the a short circuit. I suspect a poor connection somewhere in between is dropping a bunch of voltage acrossed it.
Another suspect is the small capacitor mounted near the coil. It is used the suppress noise for the radio. More than once I have seen a capacitor draw down the supply without blowing a fuse.
Another suspect is the small capacitor mounted near the coil. It is used the suppress noise for the radio. More than once I have seen a capacitor draw down the supply without blowing a fuse.
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i dont know what i did it might of been a bad connection, but i had the truck running. I shut it of to get gas now I dont get a spark. An intermitent problem that is driving me crazy. I also disconnected the suppresor.
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any idea what would cause an intermitent problem like mine. I have a scanner and everything checks out. Also I have replaced almost every component in the ignition system except for the ignition cylinder itsself. help
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Fleet Owner
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From: Kentucky
That is really odd Bill. I made my comments based on the diagram from my 1994 Ford F-series EVTM manual. In my manual it shows that pin 4 is power in for the ICM on a Red/Light Green wire. Go figure!
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From: Easton,Ks
I do not know what diagram he is using but most of the OP use fordfuelinjection.com site and the above diagrams were copied from that site.
He should have Ignition system "H".
Here is the diagram from my Ford shop manuals.
/
He should have Ignition system "H".
Here is the diagram from my Ford shop manuals.
/
Fleet Owner
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From: Easton,Ks
I have found a lot of errors in the EVTM as there are other errors in the one you posted.
They have the wire going to the computer from the ICM labeled wrong. The 1994 did not have a Start, it should be labeled IDM.
1994 was the first year that all Ford trucks went to the CCD system and they redrew the diagram. They were using the big fold out diagrams to draw the EVTM from and they got a lot of things wrong. The 1988 E-series EVTM was the worst EVTM from Ford I ever saw for errors.
I have a copies of the 1994 & 1988 big fold out diagrams they were using and I can see sometime out the error would have happen.
By the way the 1995 EVTM is also wrong.
They have the wire going to the computer from the ICM labeled wrong. The 1994 did not have a Start, it should be labeled IDM.
1994 was the first year that all Ford trucks went to the CCD system and they redrew the diagram. They were using the big fold out diagrams to draw the EVTM from and they got a lot of things wrong. The 1988 E-series EVTM was the worst EVTM from Ford I ever saw for errors.
I have a copies of the 1994 & 1988 big fold out diagrams they were using and I can see sometime out the error would have happen.
By the way the 1995 EVTM is also wrong.
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