shuts off...starts...runs fine...shuts down

[dually68]

I have a 96 3500 6.5 that needs help. As with some others, mine too, shuts off while driving. I have owned this truck since Feb. and I love it when its running. In june it gave me trouble the first time. I put it in the shop and was told that the injection timing was off. It was reset and ran fine until the other day. It shuts off, but will restart and run for about 30 seconds. If I wait till morning when it is cold it will run about 20 minutes before shutting down. I have replaced everything possible except the pcm (I think this is what it is called) Mine is a standyne unit...don't know how old it is. My question is...how can I test it before replacing it? I have already replaced the ignition switch, fuel pump, glow plug starter, glow plugs, map sensor, both coolant sensors, oil sender and about everything else.

[ace58]

Welcome. You have come to the right place. You have the text book symptoms of a FSD module failure. Do a search and you can read of others common problem. One option is to go to Kennedy diesel.com and order a new module, FSD cooler, and an extension harness for relocation. Good luck.

[tom.mcinerney]

Dually-
Nice effort so far.
As suggested above , sounds like FSD/PMD.
A clogged fuel filter can yield your symptoms. A bad load of fuel would be all it would take. Test for about 5 psi at the brass (fuel conditioner- assembly water-drain) valve with a drain hose mounted on/around the thermo hsg toward front engine; this test at idle will eliminate ops, LP, fuel filter from causes. Note if water in drain.
All your battery connections, and the battery ground cables, must be clean & tight. Also ensure the harness ground(s) at the auto trans dipstick tube [rear psgr head cover plate] is/are clean/snug--this a key ground.
Finally, when R&R PMD/FSD , don't distort the connector's pins/blades, again, a key connection.