1990 f150, 5.0L, AOD, 4x2

Truck has been sitting for a few weeks and i jump in it to go haul a load of mulch, just to find the blasted thing runs like crap....

Missing in all RPMs, sluggish, and engine shakes the whole truck. The engine is a new long block with less than 2000 miles. PVC and hose is clean.

Things tried so far:
Checked for codes. (11)
Rerouted plug wires
Checked for arching at night (none noted)
Replaced dizzy cap and rotor (needed the old one was 12 years old)
Replaced spark plugs with motorcrafts (the old plugs where new when engine was replaced, all where clean and had no noticeable smell)
Checked fuel pressure (34psi with vac, 42psi w/o vac)


I really don't want to start trowing parts and cash at it.

SO what do i need to do next? It really seems to be a spark issue.

 

Did you check the battery out?

Maybe sitting for a few weeks caused some sediment build up in the fuel tanks?

 

Look at the plug wires and O2 sensor wires, see if mice did any damage. If not you need to do a KOER test with a scanner and see what you get.

 

I have one of those battery maintainers on the truck, and did check the voltage. 12.8 engine off 14.4 engine running.

Tanks are clean, fuel pumps where replace when engine was.

No mice damage, and both KOEO and KOER only got code 11.

 

Here are a few ideas...

Cap/plug all vac lines not needed to run. You just need to troubleshoot now. Symptoms you describe are similar to a bad MAP sensor, stuck open or damaged EGR valve, bad PCM.

Check to see if the valve is open on the EGR. This sounds like the culprit. Bad honestly, it resembles a bad PCM with leaking/blown capacitors. Your getting a "Everything is good" from the PCM, but it isn't. Same problem here with my 300, as with many other members here. One thing I noticed with a bad PCM is that if I unhooked the MAP, the truck ran better, but I also had all others vac lines from the intake manifold capped and plugged. I know it sounds strange, but my 300 ran fine up till the day I parked it, and it sat for a month, then it never ran right after. 2 capacitors were the problem. They didn't blow, but leaked all the electrolyte fluid out and ruined the board.

 

Just tried checking the codes again, and the light never came on....

So i pulled out the ECM and I have to say.... must have been a leftovers tuesday truck.

I've never seen a Ford ECM like this, unless it was on a the old school smart carb engines....

Cracked it open and no leaky caps. Now what?

 

Did try to get a close up of the only cap in it but my cam couldn't focus. There was no signs of leakage.

 

Does that have a ford part number on it?

That's like no other PCM I've ever seen in these trucks of any of the year ranges. Usually there are 3 of those capacitors, not just one, that's how they cause so many different intermittent issues.

 

The top cover was stamped ford and there was part of an old ford part number sticker over the j port.

This computer reminds me of the ones that where used on the TBI set ups used in early 80s cars (vic, cougar, ect). But the internal parts are stamped with production date of 89...

 

I think you have the wrong computer there. I would suggest taking your vin number and calibration code (found in your drivers door jamb) and checking them here: http://www.motorcraftservice.com/vdi...l&type=EEFACTS

That will give you the original part number of the ECM that should be in your truck, then you can try searching images etc of the board inside to see if it matches yours.

 

It's the same computer that has been in the truck since my brother bought it back in 97, and the cap isn't leaking and none of the board is burnt. hwat i did find was the check engine light was burnt out last time i tried to get codes and instead of checking lights, fuses, and simple stuff i jerked the ECM out. So I don't expect it being the cause of my truck running like crap....

So recap:
Truck was running just fine before parking it for a few weeks. When i went to use it, it has a real rough idle like a miss, while driving it lacks power and at low RPMs and mid to heavy load (how hard I'm pressing the go pedal) the truck bucks and has a definite miss. None of the spark plug wires are arching, spark plugs are new and gaped, dizzy cap and rotor are new, and fuel pressure is where it should be. No codes other than 11....

Oh yeah... when this first started, while letting the truck idle i pulled one plug wire at a time to see which cylinder was the one missing. After a few seconds of that i would replace the wire and move to the next one. No matter which wire i pulled the truck would run worst, never stay the same. So its not just one cylinder missing all the time, its all of the cylinders missing intermittently.

 

What do your plug wires look like? You haven't mentioned changing them yet. And if you say the problem is all cylinders, look extra closely at the coil wire. Get a flashlight and look up inside the boot for rust or corrosion. If you have the cash and they're more than a few years old, change them regardless of what you find.

As jdan said, I'd look into that ECM. If it's not the right one (and the truck runs somehow???) it may not be able to output codes properly.

 

Looked up the E9TF code and found that this is a common used computer of F150s years 87-90 that had the 5.0L and auto trans. And, It has alwas worked has it should have, runing the engine, detecting problems and flashing codes that would lead me in the right dirrection for fixing any ailments the truck was having. This has been the first time, in which retrieving codes has not been helpful.
The link Jdan listed, states that i do not have permission to be on that page.

 

Not all of the truck computers had 3 capacitors in them. It all depends on what hardware code the EEC had to work with the program code. The 94 MAF EEC I have for my MAF swap has 2 capacitors in it.

 

Put the computer back in the truck, then checked all the spark plug wire ends for rust none was noted. Pulled the dizzy cap off and checked the stator for rust or bent teeth, none noted. While I was there I cleaned it up a little, just dust. Started the truck and still a miss.

So I ether am having fuel injectors not firing as they should, ignition coil not discharging correctly, bad PIP, or bad TFI module.

I plan on heading to autozoneout tomorrow and grab new plug wires, coil and some other parts in need for an other project.