hey all new to the forum here i have been literally pulling my hair out trying to figure out what is going on with my truck. it is a 1994 f150 4wd with 302 and manual 5spd

so here is the scenario, one day i was helping a buddy move a couch, we get the couch to his house and i park the truck to go inside for about 2.5 hours. i come back out to go home and start her up and she immediately dies, so i hold the accelerator and start her up again, this time she starts but can barely run, and is just dumping loads of fuel in. by now few things are going through my head.

I've had coil packs go bad on me before and it was similar so i barely get it home which was only a couple miles down the street and i proceed to replace the coil.
that didn't help

my next step was to check the tps because it was a crappy auto zone one so i figured its gone bad already, i checked the voltage and resistance and what not(i don't remember it because it was a couple weeks ago) i just went ahead and replaced it because it had a lifetime warranty, still a no go

i checked fuel pressure and it was at 35psi at idle which i believe is normal.

changed the plugs and the two cylinders on each side were wet with fuel, just those two.. i also checked the distributor rotor and cap and they looked fine.

i have a snap on obd1 code reader so i went and checked them out.

KOER
998-code definition not available
126-map, bro out of range
112-intake air temp signal low-ckt gnd
117-coolant temp signal low-cut gnd
122-throttle position signal too low

KOEO
327-EGR signal too low
513-failure in exec reference
553-air mgt circuit 2 problem
552-air mgt 1 problem
565-canister purge
556-fuel pump relay
558-egr vacuume regulator

now keep in mind that i had no check engine light prior to this...

this morning what i did was a wiggle test with that snap on code reader,
i started the wiggle test and proceeded to wiggle the harness everywhere i could reach and the reader did not pick up anything so i assume the harness is fine.

my next order of business was to check grounds so i took off the harness ground by the washer reservoir wire brushed everything and put it back on, i did the same with the ground by the battery and neither made a difference....



right now i stumped why would almost every sensor be throwing a code?????
i still think its a ground issue and am going to take the ecu off and try to check the grounds on it but what do you guys think?? bad ecu maybe??

 

Correct definition for Code 513 from my Ford Service Manual: Failure in EEC processor internal voltage.

There is your root cause. Pull out the PCM (computer) then inspect for signs of leaking capacitors and burned components.

 

awesome i surely will do that. thank you!!!

 

While you are at it note the part number on the PCM, just in case you need to replace it.



You want the numbers in the bottom photo that starts with F4ZF.

 

ok cool so disregard the numbers that are circled?

 

yes, those numbers he circled are examples from another computer...

You will need the parts numbers from your computer that is in the truck. Although, some computers will interchange just fine. If you can take a picture of your computers part numbers and post them that would be great.

 

The circled alpha-numerics are the Calibration code, while knowing that can be handy it's worthless when trying source a replacement PCM.

 

 

actually all three alike capacitors have done the same thing

 

It says 63v 10u symbol(can't remember the name of it) and the other one says <br/>16v 47u<br/>

 

Uf = Microfarad. It's a unit of measure for capacitance.

If you are handy with a soldering iron you can try replacing them. An old school tv repair shop can do it too. A few have sent them off to ECU Repair with good results.

If you want a replacement use F4TF-AVA as your reference.

 

I've done a good bit of soldering in my life i have practiced around on small circuit boards like this. I'm far from being the best but I'm gonna go ahead and try to fix it before i go to scrapyards to try to track one down. i just ordered the capacitors offline hopefully they won't take too long. luckily i have another vehicle and my truck was the back up.

thank you guys so much for the advice!! it is greatly appreciated and i will for sure keep you guys updated on the outcome

even though this sucks that this was the issue I'm very relieved that i tracked it down.

 

Yes, please keep us posted on your progress. Good luck.

 

Scrapyard will get you the same problem you now have. I learned the hard way and got 356 miles for $120.00. Repair it or buy a rebuilt. Check your circuits for breaks on the board. The leaky caps will wipe out circuits, if so just follow where it goes and solder in a small gauge wire to replace the bad circuit. Radio shack .40 & .45. keep uf same, up the volts

 

Well fellas I replaced all three capacitors, checked for continuity on all of them to make sure it was a good solder job and the trucks doing the same thing and it's actually worse now. I checked the codes with the scanner and all the same codes are there. It can't even keep itself running anymore