95 460 electrical issue
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95 460 electrical issue
Hello everybody, just created an account looking for an answer to my problem. I have a 95 ford 460 engine in a RV. Only 35k miles. I drove it a couple miles to a gas station about a year ago and when I went to crank it back up it wouldn't start. After much head scratching we found out the fuel pump wasn't coming on. So we hotwired it and got fuel pressure, but still wouldn't run. After quite a bit more head scratching (and a few 4 letter words) we figured out the injectors didn't have power. Finally ran a hot wire to the injectors and the motor is up and running good again. I can't seem to figure out why they aren't getting power, but have drove it multiple short trips with the hot wire attached (with a 20 amp fuse for safety). I'm thinking of going on a couple hundred mile trip with it soon and am looking for an answer or at least reassurance that the hotwire is ok to use. It hasn't seemed to damage anything and right now it wont run without it.
thanks for any help,
Jason
thanks for any help,
Jason
Senior User
Joined: Oct 2018
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From: Northern ID, Eastern WA
Remove your extra wires from the circuits, unplug the EEC 60 pin connector and unplug the other end of the wiring from there respected circuits. A continuity test will let you know if the harness is any good. If the harness is good then check the EEC its self. Take the top and bottom of the case off and see if their is any damage on the board.
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Joined: May 2010
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From: Central Indiana
BTW, 20 amps of current can allow a pretty big harness burn if juiry-rigged that way. That's one bush fix you don't want to entertain.
Last edited by raystankewitz; Mar 4, 2019 at 04:03 PM. Reason: Typographical errors
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Ok, thanks guys. I do appreciate the advice even if it's not exactly what I want to hear. I forgot to mention that when I hot wired the injectors the fuel pump also comes on. I think I read somewhere that the two share a circuit. It would seem that it would be a simple fuse or relay, but I've checked all the fuses more times than I can count! It must be a broken wire somewhere. But the funny thing is it cranked right up, drove it 2 miles, cut it off...and then this happened. I dunno, just thinking out loud. And the thing runs perfectly with the hot wire. Just like it did before. Def. don't want to compound my problem, but its so darn frustrating.
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You should post more information about the vehicle. Is it a van or a heavier chassis. F53?
Do you have any documentation? EVTM?
I agree. Hacks are asking for trouble.
Do you have any documentation? EVTM?
I agree. Hacks are asking for trouble.
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I'd like to add more dialogue to this post. As much as I agree with everyone to fix the problem (I'd love nothing more than to fix the problem) i really dont think the hot wire is causing any problems. I've actually forgot to disconnect it overnight. Still cranked and ran perfect. (I did have a battery charger connected, which probably prevented battery drain) Also, the injectors are ran by grounding through the computer. So the 12v constant is a normal condition. Someone please tell me exactly why it's wrong to leave it hot wired. I would really like to go on a trip this weekend.
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Brett Foote
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From: Easton,Ks
The power for the injectors and the power for the coil of the Fuel pump relay comes from the PCM Power relay.
The PCM power relay coil is powered by the Ignition switch down low on the column.
You may have an open fuse "M" that powers the contacts of the PCM power relay.
Or the PCM power relay is not closing when the key is turn to start and the run positions.
You may also have a bad PCM power relay. If so swap it out with the horn relay.
The jumper wire to the fuel injectors is also powering the PCM computer. This jumper is the same as hot wiring the system.
The jumper wire is powering the red 361 wire in the diagrams below by jumping out the PCM Power relay.
/
The PCM power relay coil is powered by the Ignition switch down low on the column.
You may have an open fuse "M" that powers the contacts of the PCM power relay.
Or the PCM power relay is not closing when the key is turn to start and the run positions.
You may also have a bad PCM power relay. If so swap it out with the horn relay.
The jumper wire to the fuel injectors is also powering the PCM computer. This jumper is the same as hot wiring the system.
The jumper wire is powering the red 361 wire in the diagrams below by jumping out the PCM Power relay.
/
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The power for the injectors and the power for the coil of the Fuel pump relay comes from the PCM Power relay.
The PCM power relay coil is powered by the Ignition switch down low on the column.
You may have an open fuse "M" that powers the contacts of the PCM power relay.
Or the PCM power relay is not closing when the key is turn to start and the run positions.
You may also have a bad PCM power relay. If so swap it out with the horn relay.
The jumper wire to the fuel injectors is also powering the PCM computer. This jumper is the same as hot wiring the system.
The jumper wire is powering the red 361 wire in the diagrams below by jumping out the PCM Power relay.
/
The PCM power relay coil is powered by the Ignition switch down low on the column.
You may have an open fuse "M" that powers the contacts of the PCM power relay.
Or the PCM power relay is not closing when the key is turn to start and the run positions.
You may also have a bad PCM power relay. If so swap it out with the horn relay.
The jumper wire to the fuel injectors is also powering the PCM computer. This jumper is the same as hot wiring the system.
The jumper wire is powering the red 361 wire in the diagrams below by jumping out the PCM Power relay.
/
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replace relays
those 2 ice cube relays are famous for causing this problem. They are interchangable despite what the parts stores say. any moisture will cause teses relays not to work. one controls the fuel pumps at start only...the other controls the start run sequence for the computer. I always carry extra ones in my glove box and, any time this problem rears up, a quick swap and off I go.
Fleet Owner
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From: Easton,Ks
The fuel pump relay controls the fuel pump when ever it runs. Not just at start up.
The PCM power relay gives power to the fuel injectors, other solenoids, relays or anything that is hooked to the red 361 wire and not just to the PCM computer.
The PCM power relay gives power to the fuel injectors, other solenoids, relays or anything that is hooked to the red 361 wire and not just to the PCM computer.
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It was one or maybe two relays. I think one might have had a bad connection and I know one was bad. I called myself swapping them around multiple times, but I wasn't doing something right. Thanks so much everybody for the great information. She's up and purring like a kitten again.
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