He should not run without the small wire from the battery to the fender. That wire is the ground for the computer so the computer can ground the fuel injectors, fuel pump relay and other items.

No I do not think there is anyway to test the PCM Computer other than subbing another computer in.





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I agree with Bill, you need the small ground wire to the body.

If everything else checks out these folks can test & repair your PCM (computer): Ecu Repair Now, automotive circuit board testing and repair

 

Okay. It's dark here now so tomorrow morn I will put a ground straight from the bat neg to the body. There is a neg bolt right near there. Personally I don't see what dif this would make as it has ran fine for 2 years without it but I will put one on and see what happens.

Also after I do that tomorrow and test that theory I am going to tarp the whole truck and put my redi-heater under it and warm that thing up to about 75 degrees and then try it! LOL! I don't know what else to do besides get a new PCM and try that!

I am at my wits end with this! It is neg temps out and I am ready to set fire to the truck just so I can work on it!

 

When you put the ground on the body make sure the two smaller wires in the photo are connected there also.
That point is your only body ground the everything in the truck uses.
Make sure the large NEG cable also goes to the engine block and NOT the frame.
You may also ground the frame if pull a trailer but it does not need to be grounded for the truck part to run OK.

 

Been away with work for a few days.

I can't see your picture Subford but I know where your talking about. I put on a good heavy gauge ground wire and nothing. Battery NEG goes to block and not the frame. I took lose, wire brushed and dielectric greased every ground under that hood! Still no luck!

Today I removed the 60 prong plug from the PCM. It had some moisture in it and the prongs from the PCM looked a bit tarnished with a whitish corrosion on them so I sprayed the plug and pins down with alcohol and used a soft tiny brass bristle wire brush to scrub in between the prongs. Then I blew it all dry with my compressor and applied dielectric to the socket holes and put the plug back on tight. Still no effect!

Oh! This last weekend I put on a new fuel filter that I already had on the shelf and was planning to put on this spring. While I had it off I turned on the key and fuel sprayed out about 2 foot. Although I still have not gotten my buddy over to bring his FP test gauge so I can test the pressure at the rail. Either he is out of town on work when I'm not or I am out of town when he is here! I think I will go just rent one from Autozone! I think that will be easier! Might even buy one LOL!

Anyhow. If you have any more suggestions on this please don't hesitate to chime right on in.

 

Oh yeah! While I was cleaning all the grounds. Over by the starter solenoid I found a wire coming out of the wiring harness that had a "Y" type spade on it. I have seen it before and it has never been hooked to anything.

Well, being Curious George I touched it to the POS BAT side of the solenoid and I heard a relay click and my HP fuel pump came on with the typical "bzzzzt" and stopped. I quickly puled it away. What might this wire be? I have seen it laying there before but have never had any reason to mess with up until now. It doesn't look like it has ever been jacked with before. It has that typical dull brass patina look to it.

Had my girl sit in the truck and watch the dash while I touched it again and she said all the typical dash lights that come on when you turn on the key came on. The BAT, ABS, and CEL call came on.

Does anyone have any idea what this plug might be for? I will take pictures if necessary.

 

Sounds like an add on wire.
A picture would be nice if you can post one. I can not seem to be able to do that anymore. I can not even see the old ones I have posted from photobucket.

 

I think it's an add on wire too. BECAUSE! Today a friend mentioned the inertia switch and I thought I might just go ahead and check it since I had some problems with the one on my old Bronco II.

While I was looking I discovered that the truck has an aftermarket alarm and remote start! Imagine my surprise! I have had that truck for a little over 4 years and have never been under the dash for anything! It's an Avital Champion Mark II. The guy I bought it from didn't mention it and I didn't get a clicker so I never knew. That may be what that wire is for. Who knows.

 

Did fuel pressure test today! Key on engine off test 40psi. While cranking trying to start it fluctuated between 38 and 42psi!

What is going on with this truck! Every test I have done proves that this truck should start and run! EVERYTHING works as it should! The only thing I have not done is pull the timing chain cover to see if it has slipped the timing chain. Could I do that without pulling the timing chain cover?

 

Did you ever put a NOID light on it to see if the injectors were being grounded?

 

Yup! I did the NOID light test yesterday.

 

I just checked the spark to #1 with a brand new spark plug and it seems pretty intense but isn't "REAL" blue. It's only got about 2,200 miles on those plugs, wires, cap and rotor.

I had a friend tell me that my ignition switch could be bad and that it could cause a no start situation and other problems. They say the same on autozone website here Duralast/Ignition Switch LS641 at AutoZone.com They are pretty cheap so I might try that tomorrow. Heck! The truck has over 200k on the chassis! No telling how many times that key has been cycled!

 

Hey Subford! Your pictures are showing back up for some reason! Cool!

 

I do not know why the stopped showing or why they started showing again.

 

I just went to a friends and pulled the MAP off his truck and put it on mine and still nothing!

I would have done the MAP test with vac and multi-tester but mine won't read Hz. I did test to see if it was getting 5v from the PCM on wire 1 and that it was getting ground on wire 3. Since that was good I subbed the one on from his running truck and still didn't get squat!

I guess I will got to AZ tomorrow and get an ignition switch and see if mine might be bad.