Gary Lewis Posted October 9, 2019 Share Posted October 9, 2019 Brandon/Bruno2 sent me a text message yesterday asking questions about the PCM on the 1997 F250 that his son, Kris/Bruno2son, has. Apparently it shuts off at the least opportune times, and may not be willing to start for an hour, or a day, or a week. So I agreed to find the '96 EVTM and scan in the pages for the diesel that are in it. As it turns out there's only one diesel listed in it - a 7.3L DI w/a turbo. So I scanned those pages in. But, since I don't know where to put them in the Documentation part of the site I'll put them here. Hope they help. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 9, 2019 Share Posted October 9, 2019 Gary, John Gleason (friend I did the 10.25" disc brake conversion for) has a 1995, same engine. He has had a couple of issues with his, one that blew his mind was oil low, apparently the oil level can get low enough that the HPOP (High Pressure Oil Pump) gets air into it and the hydraulically operated injectors don't open fully if at all. Another common issue on these is the crank position sensor with no signal, the PCM has no reference so it won't trigger the injectors. A further item, the wiring for the injector solenoids and glow plugs runs through the valve cover gaskets and they are known to burn the connectors due to the high current for the glow plugs. I would start by taking a good look at the connectors on the outside of the valve cover gaskets and make sure they aren't melted or burned. These engines are a "drive by wire" system, no throttle cable of any kind, accelerator pedal operates a resistance box that tells the PCM how far the pedal is depressed. If you look at the wiring you will also see the IDM (Injector driver module) it is an aluminum box underhood just behind the PDC on the left inner fender. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 9, 2019 Author Share Posted October 9, 2019 Gary, John Gleason (friend I did the 10.25" disc brake conversion for) has a 1995, same engine. He has had a couple of issues with his, one that blew his mind was oil low, apparently the oil level can get low enough that the HPOP (High Pressure Oil Pump) gets air into it and the hydraulically operated injectors don't open fully if at all. Another common issue on these is the crank position sensor with no signal, the PCM has no reference so it won't trigger the injectors. A further item, the wiring for the injector solenoids and glow plugs runs through the valve cover gaskets and they are known to burn the connectors due to the high current for the glow plugs. I would start by taking a good look at the connectors on the outside of the valve cover gaskets and make sure they aren't melted or burned. These engines are a "drive by wire" system, no throttle cable of any kind, accelerator pedal operates a resistance box that tells the PCM how far the pedal is depressed. If you look at the wiring you will also see the IDM (Injector driver module) it is an aluminum box underhood just behind the PDC on the left inner fender. Bill - I sent Brandon a link to this thread, so hopefully he'll see your helpful response soon. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 9, 2019 Share Posted October 9, 2019 Bill - I sent Brandon a link to this thread, so hopefully he'll see your helpful response soon. That was the idea, post something that will hopefully help. Link to comment Share on other sites More sharing options...
grumpin Posted October 9, 2019 Share Posted October 9, 2019 That was the idea, post something that will hopefully help. What Bill said, I know people who’ve had rough running PSD’s and an oil change cured it. Link to comment Share on other sites More sharing options...
Bruno2 Posted October 10, 2019 Share Posted October 10, 2019 What Bill said, I know people who’ve had rough running PSD’s and an oil change cured it. I have checked the oil level and all of the basic failure points regarding the 7.3. I even swapped the cam position sensor just for giggles even though I knew that wasnt the issue. The tach works when it cranks . When they don't on an OBS truck it is typically the CPS. The finger is pointed at the PCM. It is showing intermittent power failures. I havent tried swapping in an IDM. I have one on the shelf atvthe shop. I am pretty sure it's the PCM. I an goingbto pull it this weekend, open it up and give it a visual inspection. Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 10, 2019 Author Share Posted October 10, 2019 I have checked the oil level and all of the basic failure points regarding the 7.3. I even swapped the cam position sensor just for giggles even though I knew that wasnt the issue. The tach works when it cranks . When they don't on an OBS truck it is typically the CPS. The finger is pointed at the PCM. It is showing intermittent power failures. I havent tried swapping in an IDM. I have one on the shelf atvthe shop. I am pretty sure it's the PCM. I an goingbto pull it this weekend, open it up and give it a visual inspection. Brandon - Don't miss that you can download that file. Link to comment Share on other sites More sharing options...
grumpin Posted October 10, 2019 Share Posted October 10, 2019 Brandon - Don't miss that you can download that file. Also might try fresh oil. Link to comment Share on other sites More sharing options...
Bruno2 Posted October 12, 2019 Share Posted October 12, 2019 Well today I set out to nail down the electrical gremlin. We discovered fuse #9 (completely different than Mambo #9) was blown. Although this had never happened before I suspected it had something to do with it. While ohming the fuses in the UHD PDB I got a funny reading on #9. It started to give the audible indicating the was a complete circuit. However, it stopped almost immediately. I pulled it to findbthe infamous hanging Link to comment Share on other sites More sharing options...
Gary Lewis Posted October 12, 2019 Author Share Posted October 12, 2019 Well today I set out to nail down the electrical gremlin. We discovered fuse #9 (completely different than Mambo #9) was blown. Although this had never happened before I suspected it had something to do with it. While ohming the fuses in the UHD PDB I got a funny reading on #9. It started to give the audible indicating the was a complete circuit. However, it stopped almost immediately. I pulled it to findbthe infamous hanging Brandon - I think you posted before you were done. And I find it hilarious that you left us hanging by saying "I pulled it to findbthe infamous hanging"...... But for the others, he found a wire that was power from the PCM Power Relay to the PCM and other things that was bad and grounding out. Apparently that was causing the fuse to blow and stop the truck. He said the truck started and he was driving it home from the shopping mall's parking lot where it quit last time I knew. Link to comment Share on other sites More sharing options...
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