I have a 1993 ford f250 4x4 with the 351w and an e40d trans here is my problem i was driving one day and the truck sarted cutting out and died so i took it home and figured out the alternator had went bad and overcharged the system the distributor pickup was burnt bad so replaced the alternator voltage regulator the pickup coil and condensor truck still wouldn't run right so we started swapping parts off a truck i have we swapped the throttle position sensor the map sensor the intake temp sensor then the truck would idle but wouldn't rev past 2000rpm's so we bought a new computer and it ran fine for about 30 min the tranny wouldn't shift right and it all when to crap all over again truck will idle and rev to 2000rpm's but after that it will cut out and backfire like the ignition is loosing fire i have no idea what to do next so will someone please help thanks.

 

Have you taken your ICM in to have it tested? I believe most auto parts stores can test this units.

 

Check power and grounds to the PCM. Always a good place to start with wierd problems.

 

i have put a jumper on the ground and havent checked the power how would you do that, the icm is the same thi9ng as the pcm right

 

The ICM is the the Ignition Control Module. On your truck it is normally mounted on the driver's side fender. The PCM is the Powertrain Control Module also known as the EEC-IV. It is mounted behind the driver's side kick panel.

 

ok changed the icm and still no luck, does anyone know which wire is the power wire to the computer?

 

The power wires are in the EEC-IV connector that goes through the firewall below the booster. It has a 10mm bolt right through it that you unscrew to disconnect it. Disconnect it and use a multimeter or a test light looking for power and ground. The other thing that can cause big problems is the relay for the EEC-IV system. I am not totally sure where it is on that year model but look for it. It will have 2 big wires, 2 or three small wires, and the connector will likely be brown. Look around the air cleaner or the power distribution box if it has one.

 

Here is a picture from Subford





The PCM Power Relay is in the engine compartment power distribution box

 

Ok i changed the engine wiring harness and the injectors and have another computer coming (warranty) to put in bc i found a bare wire in the harness that i think was grounding out and i think it might have zapped the new computer. The reason i think it fried the computer is because the truck ran great when i put the new computer in it til i went muddin and the longer i romped on it the worse it got till it was back to before i put the computer in it.