my father just bought a 1997 chevy 3500 express box truck 6.5l. im not to familiar with these 6.5l so any help would be awesome. anyways bought it last week 100k on it i went through it, oil/filter, fuel filter, new brakes and it seems everything is ok. i started it up several different times and it was fine. then i started and the 2 mins later it shut off. so i started it bak up. another 2 or so mins shutdown again. so i started thinking a fuel issue but it started again i let it run for about 30 mins and it was fine. i dont know too much about these i work on powerstrokes for a living but any sensors or this pmd thing im reading about. any help is great.

 

Is he PMD in the stock location stll (on the side of the injector pump)??? if so this may be the proble have youpulled the codes yet???

 

PMD or bad ignition switch,does the dash die with the truck but radio and blower motor keep running?If so ignition switch.
Otherwise get a PMD relocation kit or build your own with a new PMD,a heatsink and PMD resistor as well as a PMD extension harness so the PMD can be mounted outside the engine bay.

 

sorry took a while to get back. if you ever have to relocate a pmd on an express 3500 6.5 just buy the whole relocation kit with a new pmd. i learned the hard way by not doing my homework but to get to the pmd you gotta take the intake manifold off on driver side some of the wiring you have to disconnect and move out of the way, the a/c compressor, air cleaner, you can leave the fuel lines. but you cant get to the bottom bolts of the pmd without taking off the fuel pump, dissconnect all the fuel lines and remove the pump. so i wasnt gonna go through all that i didnt have the time. ended up buying a reman pmd, and the relocation kit, and left the old pmd still mounted on the pump.

 

Yes once a PMD starts to show signs of failure-there is no saving it anyways,most folks do just leave the dead PMD where it was.

 

OK, because your problem sounds a bit like what I am experiencing, will share where I have been guided to look-
+starts fine when cold
+runs fine till comes to temp
+when comes to temp, timing drops off 8deg (as read on Snap-on scanner) to 0deg advanced
+idles like crap
+if hold accelerator pedal, rpm slowly increases
+when hits 1200 rpm (think that was the number), timing advance kicks in again (8-10deg) and runs great again (till I let rpm's drop below 1200, and starts over)

Notes: problem started after / while (did monthly starts) sat parked for about 10-11 months. Thinking occasional jump starts / very (very very very) limited use of either to start might have contributed.. Just for giggles I am going to locate temp sensor, disconnect, and see if triggers different outcome

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UPDATE!!!! Just for S+G, disconnected what I think is temp sender (plugged in by upper hose to plenum). Got cod P118 (low voltage temp sender)
let idle for a bit, drove around block. Kind of threw me that although it seems I unplugged sender, gauge increases, snapon brick shows temp
guess what?
timing stays at DES, RUNS (and continues to) GREAT

Back to S+G, reconnected sensor
about 18.117 seconds later, timing fell off to 0, idle / throttle response went to crap
disconnected sensor, RUNS GREAT
WTF?

 

ECM temp sender is in water crossover manifold,gauge temp sender is in drivers side cylinder head.

 

what he said^^^^

my success was by disconnecting sender in water crossover

edit: when I said "idles like crap", meant "died if I did not keep foot in throttle, took while to work up to
~1299 rpm (at which time / up ran fine)

passed emissions yesterday flying colors