I have a 94 6.5 turbo deisel it run fine and then it struggles and it shuts down I'm getting fuel I think its my injection modual I think its also called the FSD when I'm having problems it is really hot and when it runs good you can unplug the FSD and it will do the same thing My FSD has been moved from the factory location but its still on top of the intake and it stays really hot do I need a new modual or do I just need to move this one or I have heard people talk about coolers or something Please help I am new to the deisel world Thanks

If you unplug the FSD the truck would shut down immediately, it wouldnt stumble and it wouldnt start. So if you unplugged something and it didnt shut down it was not the FSD.

Make sure your LP and OPS work.
On a 94, to check OPS start truck up and check for 14V on pin G of the OBD1 port, bottom left. If no voltage OPS is not working.

To see if LP actually works without truck on, check the fuse on the passenger fire wall, then push the fuse top, where this is a slit, up on a battery junction post next to it. You should hear pump come on. Open up the valve by the thermostat and put the drain hose into a container and see that it flows healthy.

then it was the FSD because it dies instantly and when you plug it back in it won't start for a few minutes but the truck is more so missing and loses power and then it just dies instantly I'm pretty shure that is my problem but do I just move it were do I move it or do I need to get a new one and move it THANKS

also can you tell me wut FSD stands for also LP and OPS like I said I'm new to the deisel world I have work on alot of gas motors THANKS

FSD - Fuel Solenoid Driver also called a PMD - Pump Mounted Driver
LP - Lift Pump
OPS - Oil Pressure Switch

DO the diagnostic checklist carefully. I think you may have more than 1 problem.

The expert here can help you guide and makes better suggestion to help fix your truck.

Yes do the checklist in the FAQs, but this does sound like an FSD problem. Even if your FSD is not the problem, it is a good idea to get one of the extension cables and mount it in the front bumper, that will help keep it much cooler. The intake is just as bad of a spot as the on the pump really.

Thanks for the help I just got back on here and got yall's info but I moved the FSD into the front bumper yesterday I made my own wiring harness and so far 200 miles no problems but I was not sure wut I was doing was a good idea but after reading yall's replys I guess it was THANKS AGAIN !!

Glad you fix it. Still get a new one for spare because moving it out will not revive the PMD/FSD.