thanks for help in past repairs, here's one over my head. Not a mech. but a parts changer if I know what the problem is. '94 f150 w/ 5.8L with over 200k mi. Started up, sputtered a bit, once around the block to warm up and seemed ok. Backed up to load some furn. and stalled dead. Now will not start. Cannot hear whirl of fuel pump. After reading other posts, used jumper wire at #6 spot by dr.side (don't remember it's name) and I can hear the pump noise I used to hear briefly when starting truck. Checked inertia switch and it is in proper position, although I don't know how to tell if it's bad and is the problem, or it's something else. I checked the fuses under dash and hood, and look ok. I'm not sure if I know what a fuesable link is, but I checked what I think they are up on the pass. side wheel well by battery. Ground cable at radiator support looks good. Can't find the little black wire with red stripe by battery for possible ground problem. ANY HELP OR SUGGESTIONS APPRECIATED. Please not too technical unless you don't mind me contacting you to walk me through the steps. I think my oil pressure sensor is bad, reads below nothing, could this be a contributing culprit? Thanks

 

When you jumped pin #6 if you were shorting it to pin #2 then I would say you need another PCM Computer.

When you jump pin #6 to pin #2 and the fuel pump runs but not when you just turn on the key the fuel pump relay, the inertia switch, ground at the battery/body and the power relay are OK.

Not much left as we know power is getting to the coil of the fuel pump relay so the PCM computer should have power on its power pins also.

That is why I say sounds like the PCM computer is bad. If you can not find a good one you can take it to a electronics shop and they can replace the caps and check solder joints for you and that may be all it needs.

It is located in the drivers kick panel but must be removed from under the hood and through the fender and inter fender with the front tire off. You will have to take the screws out of the inter fender and pry it open with a broom handle.

The bolt in the center of the plug is 10mm and you back it out as the plug comes out. there is also two nuts one above and one below the plug that has to be removed after you unplug it before you can pull the PCM out.

PCM location:




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wow subford, way to help out.

I'd agree with subford, unless something finicky is happening with wiring somewhere, sounds like eec is good place to start. a universal "symptom", although not a guarantee (there are no guarantees), of a failed eec is the fuel pump not priming when the key is turned to on.

my suggestion to you is to find an eec in the junkyard. you'll need one out of a truck that has your trans, ignition module, and sensor configuration (maf or SD) in order for it to run normal. however, just about any functioning eec will start the truck and confirm that it is the culprit. the reason I included this is that you may not find your exact eec in the jy, but there will be one there that you could use at least for diagnostics. theyre cheap also.

 

Here's what you'd be looking for in the PCM.
Click this link: A9x ECM's (and same years ECM's) Failures Due to Age

And yes, Subford IS THE MAN !!

Bob

 

holy cow. Weather just got dry enough to work on the truck. (all outside) Less then 30 min and the part was in my hands. No doubt you guys are aces in my book. One thing, I cannot find anyone who is willing to attempt to replace the capicitors or even take a look. I'm not giving up yet, going to try a couple of places within 45 or 50 miles. I understand this is an 8 layer board and overheating the solder can burn through the 1st 3 boards pretty quick. (or is this just bad info to sell me a new part?) I was told I need someone who is qualified to work on microprocessors, the local computer repair place wouldn't even talk to me about the repair? go figure. Any suggestions or would you just ask the guy at radio shack? Thanks so much and I'll keep you apprised of the outcome. oh btw, after my 1st repair from this site about a year ago, I got the truck running after sitting for a year and finally named it . "Lazarus"

 

Most replace the capacitors themselves but I would think a TV or Radio repair place could do it also.
I have heard the PCB is four-layer but I am not sure on that as I was thinking it was not a layered board, just two sided.

 

This is what I found. Any opinions as to whether the entire board is shot or do you think the capacitors themselves can be replaced and I'm back in business? Sorry I don't know how to post the pics. The board has a scorch mark that runs from the capacitor down the width of the board. Any thoughts without seeing the issue? If anyone wants to email me directly I can attach the pics to an email and send them that way. thanks

 

You can email me the photos and I can post them here for you.
My email is at the bottom of this post.

 

Here is your image:
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Thanks for posting his picture for the rest of us to "observe".

If that were my PCM, I'd start looking for a good replacement and not even fuss with the capacitor replacement.
There appears to be many surrounding circuits that "may" have been affected buy the leaking electrolyte.

Just my opinion though.......

Bob

 

Thanks for all the step by step help from everyone. I now have a rebuilt PCM and my truck lives on. True to the name I gave it after I first found this site and got it running. Lazarus is now on the road again. Until next time, Many Many thanks, Robert