Working on a 96 f350 for a cousin. 7.3 powerstroke with 265k. No start/no smoke. No communication with my launch scan tool or a generic code reader. The truck has a jackwagon edge evolution tuner that will read and clear the codes. Its not offering any helpful codes though- back pressure sensor code and low voltage- probably from Long cranking. Heres what I've checked- Fuel pressure to the bowl is well within spec. 35 psi- minimum of 20 to start. The PCM has power, key on power and all 5 grounds ohm out good The IDM also has power and ground. I even ohmed out the wires that run between the pcm and idm. All have good continuity. A friend had a spare pcm and idm. I put both those in with no change. Still no communication. The high pressure oil pump reservoir is full, engine oil is full as well. The check engine light flashes, the wait to start light is coming on. The tach moves when cranking and the tuner also picks up the rpm. This tells me the cps is reading. I did pull a few connecters to measure voltage. The map sensor, ipr sensor are both getting a 5 volt signal. I did this before i had a spare pcm- i was hoping to find a dead pcm. My next move is to ohm the wires between the pcm and obd2 connector. If anyone has a diagram for the obd2 plug that would be great. My gut tells me the hpop is shot. The truck had some starting issues in the past and would sometimes only start with a tow (5 speed) If i can get the scan tool to communicate i can read the rail pressure in the data. A mechanical gauge can go on as well but it's not in the budget for a 1 time use. My other thought it reading the value on the ipr sensor and convert it over. It has a 5 volt reference, it must send back 0-5 volts back to the pcm depending on psi. If anyone has access to that info that would be great. Any other tips or suggestions are welcome. A pin out of the obd2 plug would be great too. I need to communicate with this rug boat! Thanks
