lanwickum

Ok, anyone seen a GEM module cause a no spark issue? I was sure it has to be PCM. Did more testing and the burnt transistors, I thought they were burnt, looks more like residue from previous repair. The GEM will not communicate to computer and will not program. Wires to OBD all test good. Split the GEM and it had something dumped inside of it. This car is mess. Another thing, I had the PCM removed and the PATS system seems to work? At least the dash light worked as it should. I thought the PCM controlled it? GEM module is fairly cheap on ebay so I ordered a used one. I will try to keep people updated if I figure this out. I also tore the PCM apart enough looking and testing I would prefer to replace it. Ordered one off ebay for cheap. I hope I can program it properly. If not the old one may still work fine.

With a network test I also found the GEM module failed. The anti theft light goes out when I turn on ignition. Does the GEM module need to communicate with PCM? If it doesn't could it cause a no start? I find no problems with any functions in the cab.

Purchased this from an older vet that needed the money for another car. He had it at a couple shops and had to give up due it getting to expensive. Was told the other shops put in 2 crank sensors, 2 reman pcms, new coils, new spark plugs, new battery, new injectors. Before hauling home I had the ford dealer hook up to it and see what they could find. It looks like it should start. Everything on PCM seems ok, PATS shows ok. They did ohm check the crank sensor even though it shows RPM during cranking and service engine light goes out. They said the 280 ohms is low. It is a napa sensor. I do have a Chinese VCM II and I find only 1 odd thing. Tried a relative compression check just because. They diffrence in % and the mean RPM all show the same number. A 10 digit negative number of -2147483648. That is odd. Double checked and there is no spark. Have battery voltage during cranking at red wire and the other wire does not flash ground at all. Tried to put test light from + to wire and nothing during cranking. What else.... Engine coolant temp shows ambient temp. Read of strange problems when temp sensor fails. Crank sensor shows 0.8V or so AC when cranking at plug on top of engine when back probed. laptop shows good fuel pressure when turn key on and can hear pump turn on when turn key on. Passes leak down test. Any advice? Or something anyone has ideas on to check? About to send in the PCM again for a 3rd one. I do have some Ford crank and cam sensors ordered since they are cheap enough.