Hey all, posting up here strictly as an F.Y.I.. My F350 had an EEC failure last week and i had a hard time finding the right details to troubleshoot.
1994 F350 7.5L e40d 47,000 miles

Thursday/Friday i was installing a septic system so my truck was doing her usual pulling trailer with skid-steer behind then running around to pick up materials. It was very hot here whilst pulling but all went well. I noticed at one point the idle was a little lopey while unhooking to head home for the day, diddnt think much of it because she worked hard on a hot day and ran without issue otherwise.
Saturday I went out and started the truck, let idle for 2-3 min before i left as i always do. Just as i grabbed the shifter to put in drive the engine quit, just like i turned off the key. This has never happened, no CEL. Cycled the key once and cranked it over, crank but no start. Suddenly i smelled a light electrical smell like smoke was coming out of the wires somewhere. I shut off the master switch and looked things over. Nothing was hot, electrical smell seemed to be coming from under the dash somewhere. At this point i had to go pour concrete so i left her there to think about things.
Suspecting a fuel pump failure, I came back with a fuel pressure gauge and started troubleshooting. Now the truck will start but runs very poorly for about 30 seconds then shuts down.

Symptoms -
Electrical smell in cab under dash
EEC relay has power and cycles from ignition switch, ignition switch contacts look good. No blown fuses
Crank, no start. Sometimes start but runs rough, CEL not flashing but flickering along with fuel pump signal
Fuel pump runs constantly at key on, engine off, holds steady 40PSI at the rail. (pump should cut after a second or so KOEO)
Fuel pump cuts after engine running (rough) for about 30 seconds. Fuel holding 40PSI at the rail when idling.
After fuel pump cuts when idling, fuel pump runs and holds pressure using EEC test connection.
EEC test connection shows no codes... no 111, no nothing. No CEL when key on Engine off, or cranking.

At this point i found a youtube video showing a truck with a suspected failing EEC, symptom of the fuel pump running constantly after the key is set to on rather than a couple seconds. I pulled the EEC and opened it up. Capacitor failure for sure, looks like a bomb went off and smoked through the board. Ordered a replacement from Rockauto. replacement is a reman, but has all 3 capacitors looking like they were replaced. After assembly she runs good as new again.

Hope this symptoms list helps the next guy, thought i'd give back for all the times im on here. The tell tale appears to be the fuel pump running constantly, then the sudden shut down. I'm guessing when it would idle but rough there was enough left in the board to keep the pump running until the board got hot and it would shut down until it cooled. I was very tempted to replace the capacitors myself, until i flipped it over and saw how burnt up the board was.

Reman on left, smokey on right


Capacitor failure

Back of board

Back to work

 

Hello,
My name is Steven. I have been fixing PCM's for people on this board offering free parts and labor. I have fixed about 35 computers so far. It looks to me like a tantulum capacitor blew. When a tantulum goes bad it shorts out and pops rather than leaking like an electrolytic. I cannot say for sure what happened from the photos.
I am currently working on a PCM that had an electrolytic capacitor puke its electrolyte onto the board.
The fluid traveled under the conformal coating and found its way to the back side of the board. The fluid has corroded quite a few of the copper traces and the legs of other components although I can fix those issues.
What i don't have are the IC's and transistors if I need to replace one.
The IC's and chips are unobtainium parts and where only made for the EEC-IV boards and not available to the public. Some can be found as long as you buy 100 of them.

What kind of deal can we make for your bad PCM so that I have a few a few parts to help out fellow Ford truck guys ?

 

Hey glad you are keeping these alive. Send me a PM, core is $85 if you can be close to that i dont mind sending your way. I can get some closer pictures of the damage, I planned to send the core back on Monday.

 

I forgot about the core charge. I'm on disability retirement and I fix electronic stuff in my 12x12 shack to keep my wife from shooting me. I'm very well equipped to fix just about everything but I don't have the $85 to buy your PCM.