ford gurus: 89 E-150 running very rich...

[zoman]

here's the deal, CTS, ACT, TPS sensors are working correctly, MAP sensor frequency/Hertz readings are right on the money, but the darn black smoke out the tail pipe and fast plug fouling does not cease. I have checked all pins and signals/voltages/readings on PCM, including all circuits for shorts/opens and all reads ok. I have tried sensor simulator on everything controlling fuel mixture to no avail. The scope shows wide injector pulse width even when a "hot idle" is simulated. I have spent many hours trying to figure this thing out and I think it's time to bite the bullet and get a new PCM?? Off idle the black smoke is reduced slightly but still visible. MAP has a three wire connector, I read good ground on ground lead, 5volts on VREF lead, and 5Volts on signal lead with MAP disconnected. Now, I don't know if I'm supposed to read 5v on signal lead(the middle wire){when MAP is hooked up, KOEO, signal wire reads about 2.5v, specifications mandate about 1.5v @ about 4000ft elevation...}; would anyone be so kind as to check this for me on their good running vehicle equipped with a MAP sensor?? Anyone have any ideas?? this one's making me pull some hair off my scalp!! What the heck am I missing??? T>I>A>...

[zoman]

well, van is fixed, PCM was bad after all...got a new one, installed it and van ran like new, no more black smoke. About the voltage on the signal wire, well, it's normal cause a couple other vans/trucks w/ same powertrain showed similar to this van...glad to have it running well, what a PITA this thing was!!