Hello All\help..94 Diesel Stalling Problem

[collision guy]

Hi to all on this great board.I had someone tell me to check out this site when I was having problems with my 1994 GMC 2500 TURBO DIESEL.I bought the truck as a theft recovery and now I am starting to think the old owner had it stolen to get rid of his\her problem vehicle.The truck runs great but the problem is that it will stall every now and then.Most of the time on idle,the odd time when driving.When scanned there are no codes at all.The only thing was glow plug relay wasnt getting 12 volts.We checked all battery connections,wiring harnesses,connectors.Changed fuel filter, fuel pump relay.pulled tank,repaired sending unit pipes,checked tank for crud.Last nite I thought we found the problem,loose\dirty battery connections.Cleaned up batteries and connectors.Drove problem free for 2.5 hours.Parked for 1 hour.Started truck stalled restarted drove home.Drove to work next day shut off.Restarted truck and left idling,stalled 10 minites later.Restarted stalled again.STARTED AND RAN FINE..We even had scanner on truck when it stalled NO CODES....PLEASE ANYONE HELP...I WILL PAY FOR ADVISE...I AM STUMPED....Thank you..

[02F2504x4]

Ummm starts up fine runs great right? And when idling dose it sound like its not getting fuel to where it dies? I don't know if this will help but I ran to a problem like that today actually... I replaced a timing belt on this car it started fine ran good till idling and then stalled... So I went back and adjusted the throttle cable and its fine now. I not sure with the throttle looks like on your 94 GMC but hopefully this helps?

[collision guy]

Hey 02F2504x4 thanks for the reply.The throttle in my 94 is electric,no cables.The truck idles fine then quits all of a sudden.Like the key was shut off,no signs at all it is going to die.The odd time just before a stall the truck would have a little miss then stall seconds after miss.Some seem to think it may be the PMD (PUMP MOUNTED DRIVER) on injector pump.$600.00 PART.NO RETURNS.Does anyone know if the PMD is bad or failing does it always leave codes or can it be bad with no codes.Thanks again for your help......collision guy

[TMHark]

I've got a 97 and went thru the exact same issues.

The injection system on the electronic controlled GM diesels of that vintage are NOT up to snuff. Things to check/replace:

OPS - Oil pressure switch. Sends voltage to lift pump to help with main injection pump fuel priming/delivery. Not HD enough and will fail.

Lift Pump - On frame rail under driver seat. Helps push/prime main IP. When this fails truck may or may not run properly, but puts a MAJOR strain on main injector pump, to the point where it runs super hot. Should run at all times engine is running. Can cause $1000 main IP to fail.

PMD (or FSD) - This is what normally causes the dreaded STALLS syndrome. Do NOT put a new one in stock location(piggybacked on main IP). When the IP gets hot (usually due to OPS or Lift Pump going bad) it cooks the PMD and the stalls begin. You can get one on a trick heat sink that takes only about 5 minutes to install (as opposed to HOURS in stock location) for way less than putting one on main IP where it can get damaged again.

Places like SSDieselSupply.com, HeathDiesel.com, and KennedyDiesel.com all sell these parts and provide support and encouragement for this engine line. For info, check out the forums that also deal with these problems. DieselPlace.com and GM-Diesel.com seem to come to mind.