Okay, I will check tomorrow for sure but, from what I remember the other day was... I had constant power on one side of the connector and did not get any pulses on the other side.

 

You'll need a wiring diagram to determine which pin on the PCM plug is inj gnd. When you find it, you can run a new wire to the injector connector and splice in at both ends.

 

Okay, today I started troubleshooting again....here is what I found. I traced the wire back to the battery side of the engine compartment and ran a new wire from the injector plug to the matching wire next to the battery. (it goes to a plug that leads I guess into the cab to the PCM?) when I start the truck up the test light flashes..and I still have the miss(from what I can tell). Then after about 10-15 seconds it stops flashing. I checked another injector wire and it stays steady. When I shut the truck off and restart, the test light flashes then dies after 10-15 seconds. It will do this every time I start it. Another strange thing is when I shut the truck off, the test light lights up steady. I checked another injector and it does the same thing (stays on with the keys out of the ignition).

Is this normal or another indication that my PCM is shot?

Thanks for the help....Has anyone had this problem before?

 

Haven't seen this before on a Ford. I'm a little unsure without actually working on it, but I'm suspecting a bad injector driver in PCM. Just for the record PCM failure on it's own is not common. But PCM failure as a result of a shorted injector is not UNcommon. If you decide to swap out a PCM, you may want to check resistance across all injectors first-so as not to fry another PCM (if that is indeed the problem). That's a tough one for sure!

 

Okay thanks. I'm at a total loss here and I really hate to throw money at it.lol

If I pick up a junk yard computer I gather from reading that the dealer has to install it and program it? If you would know what is that going to cost? I haven't taken anything I've owned to a dealer in over 20 years.

If that is my only option I will have to limp it up to the dealership, pull the old computer, install the new one and push it into the stall so they can work their magic..? Does that sound about right?

Thanks...

 

If you buy a used PCM it should already be programmed. It may not be the most up-to-date program but will run the engine. If you buy a new or reman PCM it will need to be flashed.

 

That would be nice but what about the PATS system? Doesn't it have to be programmed by Ford to recognize my keys and such?

 

Okay, what about this...if I still have a miss fire on coil number 7.... Would the computer shut down fuel to the injector so it doesn't burn up the cat converter? Maybe that is why the injector loses power after 10-15 seconds.....grrrr, back to pulling this thing apart again....

Btw, I'm still open to suggestions!

 

No it will not. The PCM won't know why it's misfiring. Itg just knows that CKP signal isn't showing the crankshaft speeding up upon the cylinder firing.
I don't think the PCM change will affect your PATS. It's controlled by its own module.

 

Okay..well rechecking everything again. I pulled the PCM yesterday to get the numbers off of it and then put it back in place so I can move the truck. Still same issue... I start it up, injector is firing for 10-15 seconds (runs real smooth as it should) then test light stops flashing and stumble miss comes back. I rechecked the COP and it never misses a beat. I guess I need to man up and buy another PCM. That is he only thing I can think of, it has to be the injector driver in the PCM.

I called Ford and the service manager told me it would have to be programmed and that would run me about $150. (I'm not doubting you, just going off what he said yesterday).

So now as far as the PCM...which one? There are several on eBay and I only found one with my nearly exact number. All the rest stated fits...2001. Ford F150 5.4. Should they all work? Mines a 4x4 but I do not recall that part being listed.