'00 5.0L PCM operation

[TestPoint]

You may recognize the never ending saga from my 'handle' but I am putting an '00' Explorer 5.0L into an old Volvo. It is now running . . . but the the #1 cylinder is not firing. All other cylinders work fine. No related DTCodes.

New plug. Observed blue spark on plug laying on engine ground.

The PCM side of the injector reads the 13.6V as I would expect but does not dip on 'injector operate' ground from the PCM. I observed other injectors dropping the voltage down to 4-6v on the PCM ground side. That is really only a sample based on a 500 per second test by the VOM and the PCM timing of the injector operation so it jumped all over the place.

Measured from the injector connector to pin #75 of the C202 PCM harness at 1.7 ohms. Cleaned the male and female connectors there.

Read hi resistance (over 20k ohms) changing grounds on the #1 'tan' injector control wire from the PCM. You have to go to the 20K scale to even read it.

Replaced the #1 injector and still get the same result. I now have a couple spare if anyone needs one.

The really strange confusing thing is that with the injector connector off the engine runs as if one cylinder is dead. With it on it feeds gas into the exhaust with little explosions. Unless this strikes a note with someone disregard for the moment.

Spent a couple hours this morning with a couple PCM rebuilders/tuners in FL. Bottom line is that they wanted $250 for a guaranteed PCM. Then I would have to disable PATS, AGAIN, and one went on to say that I would have to have it reflashed at a FORD dealer.

Plan B: My long time technical coach at the local Ford dealer has now retired. I know where he lives. I am going out there tomorrow morning and see what he has to say.

What say you?

 

[TestPoint]

Just to wrap things up . . .

After 3 weeks of testing and replacing I realized that the plug wire pairs on the coils were horizonal on one coil pack and vertical on the other. That couldn't be!

Can you believe that I:

Removed all plugs and did compression test . . . twice.

Replaced the PCM and reflashed the new one. Now I have a spare.

Replaced the injector twice after removing the throttle body each time. Now I have 2 spares.

Rewired the injector control lead

Replaced the coil pack twice. Now I have 2 spares.

Drove 200 miles to pick up parts

All over three week and no count of hours of sleep I lost . . .

. . . over a coil wire error.

And in case anyone needs the coil to plug layout here it is.

.

 

[2000StreetRod]

running good?

Does that mean that you now have the engine running good? If so, congratulations!

What about the vehicle speed sensor? Is that a problem?

 

[Turdle]

Forgive the non technical language, however, I believe one bank of plugs fires from ground to electrode, and the other from electrode to ground.

Something I read here that might make a difference in this discussion. Sorry for butting in but this might help.

We've all crossed a few wires--glad you found it!!

 

[TestPoint]

StreetRod,

Running good! Took it out for 20 miles today and nothing fell off . . . that I noticed or missed.

I guess I determined that the VSS is only used for 4WD. The electrical page for it only appears to be connected ICW 4WD. It clearly says on the electrical schematic page for the trans OSS that the signal is used for shift management. Shifts through all the gears as I would expect but I haven't had it up to highway speeds yet.

Yeah, I had read that originally the engine came with platinum electrodes on one coil and non plated on the other. Everything now runs on platinum. That was too complicated for us shade tree mechanics to deal with.

The plug wires were as the engine was delivered so I never thought to verify that they were correct. The confusion factor was that only one cylinder did not fire based on exhaust pipe temp. Problem was that #3 was firing after TDC but firing none the less and the pipe was getting hot like the other 6.