Truck Repair: 1995 gmc 6.5turbo no start, oil pressure switch, coolant temp

Question
hi, i am actually a mechanic, but this truck has stumped me.my truck has no codes,but all the scan data is no good,it shows with the key on,engine off, throttle position 20%,rpm698,coolant temp on scanner is 151,even if you unplug the sensor it stays the same.I have tried many things such as new standard computer,oil pressure switch,driver moduel,gas pedal, and fuel pump relay. i have check all grounds, and all the wiring going in and out of the computer.I even unplugged the main harness at the engine, and no numbers changed on the scanner what so ever.

Answer
Hi Jeff,
I don't know about the code scanner...I would surely check the ECM fuse, as well as the others.

I have had to get the injector pump replaced for dying, but they increased the warranty to 10 years, 100,000 miles at that time, so it was free. I'd at least ask about it.

There is also known problems with the FSD which is the Fuel Solenoid Driver overheating. Look at this search. http://www.google.com/search?hl=en&q=GM+6.5+diesel+driver

Van