Hi Guy's.I have an 88 F250 with a 460 engine.It all started in June.My boyfriend drove my truck to the store.It wouldn't start back up.He thought it was the neg. battery cable.He rerouted the new cable to the generator bracket.It was fine.Then a few days later it did it again.He replaced the positive.Then it wouldn't start again.I put a ignition modular on it.It ran fine.Then it started running rough and running codes.I replaced about every sensor I could find.Off to the shop it went.They replaced the pick-up coil.Got it back and it ran like a scalded dog.Stopped at the gas station where I put 30 gal. of WATER in my tanks.It was sent to the dealers where they pulled both takes and cleaned it out.The next day I drive 135 miles 1 way to pick up a horse trailer.It ran great all the way there and back.Next day it ran like crap.Of to the shop again.He said it was the ground on the PCM.He said the PCM maybe going out.Got it back it ran great again.The next day I couldn't make it out of the driveway.I replaced the PCM. Same thing.It went to a different shop.They said they performed a Balance test and that cyls # 1 #5 #4 and #8 failed.They told me I needed a valve job and the cyl. were dead.I may be a female but even I know cyls. don't go dead over night.I was talking to a friend I told him about it.( I had bought the truck from him years ago) I took it to him.He checked the injectors.And the # 1 #5 #4 and # 8 injectors were not working.Tonight I got my book out and it looks like those 4 injectors share a wire.My thinking is It's the wire.It's the tan/org. wire at pin 58. Now for the question.Which pin is 58 on the plug.I know that it is the tan/org. wire but a few wires look close in color.My thinking is to jump the wire from the back of the plug to the start of number 5 injector to see if I could maybe bypass the problem and narrow it down.Does the plug that does into the PCM go bad? Sorry this post is long but I wanted you to know the facts. Thanks Guys.

 

EEC computers very seldom go bad, if you still have the old computer I would put it back in.
Sounds like the new one is bad. If you do not have the old one take the computer back an have them give you abother one.

Here is a link that has a pin-out of the EEC computer plug:
http://fordfuelinjection.com/?p=3

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Subford I think you are right.I checked the wire going from the PCM to #5 inj. and it is good.Has to be the 58 pin on the PCM. I went to O'rileys and they could not find any in their warehouses.If they can't get one for me tomarrow Im going to Napa.Thank you for your help.BIG HUG

 

Subford..YOU ARE A GENIUS.Got the replacement PCM and it runs great..I have my truck back.I have been trying to fix my truck since March and it was the PCM the whole time. I'm glad I'm stubborn.My boyfriend wanted me to buy a new truck and junk this one.I told him I will have my truck LONG after he is gone..LOL..Thanks again..BIG HUG