Hello everyone,
I have had this truck for 12 yrs all stock 240,000 miles.Spent lots of cash$$$$ and a lot of busted knuckles to keep it running.
Anyway, the truck is spitting sputtering sometimes stalls mainly rite after starting up.
i suspect it being a fuel delivery problem.It does have an after market remote PMD w/heatsink on my third one figured try after market with a heatsink this time. Its about a couple years old.
IP has been replaced twice.maybe 4 yrs old. vacumme pump about 1yr old
i am trying to test the LP .had the truck running opened the pit **** no fuel came out then stalled. same with opening top of fuel filter canister.the only time i can get fuel out of these is when i am cranking the motor over. So now i get truck running again I check the voltage on the plug for the LP and only get 6 or 7 volts .My question is it should be 12 volts right? would the oil pressure switch play a part in this? Any ideas what else to check ? How about the fuel relay switch?
thanks again for anyone with the answer

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well, ran a few tests this morning.i tested wires on oil pressure switch.with key on orange wire
12v ,tan wire 7-8v lime green 0v.Now ran a splice from lime green wire with truck running
got a 7-8v reading .now went back to LP there is black wire i'm sure this must be ground and a lime green wire for power now is reading 14v what a differance from last nights reading 7-8v. I didnt think last night to check oil pressure so no reading on that. too pisted-off by then.Now also tested the fuel pump relay,

0v -o o- 0v when key on ,7v- engine running

-o o- o- 0v
^ 0v
12v key on ,14v engine running

hope you understand diagram of relay.wish i would of checked this last night.
Today truck is running fine with the exception of
code 33 = egr control pressure/baro sensor circuit high (low vac) Once service light pops on loose a bit of power.I just put in nuetral and restart truck.then ok till i get on it again.
Any idea how to fix?
same thing going on with no fuel coming out of pitcock or filter when truck running ,only when cranking motor over.

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ok? did some more wire testing and jumping tests.i ran a wire directly from battery to LP pump ran opened pitcock lots of fuel.
Next i tested the voltage on the wire that runs from the OPS to the pump, with plug not plugged into pump, key on 0v, 14v engine running. I hooked the plug back up to pump only reading 7-8v with motor running. And pump is not working.I still think that pump should kick on with key on.
next i tested the fuel pump relay again with unlpugged to fuel pump 14v .plugged in pump 7-8v
so i am going to purchase a oil pressure switch. If that aint it i will run a toggle switch. Screw it

 

problem was solved with replacing the oil pressure switch.so hopefully this will help someone down the road. I want to thank for all the responses I have received. (0) THOUGHT THIS WAS A SITE TO HELP FELLOW DEISEL OWNERS!!!!!!!!!!!!!!!!

 

Sorry for the slow response.... I have been checking the 6.5 forum every day for a week would have answered had I seen it. I think what might have happened is you posted in the General Forum for Chevy / GMC. Great Troubleshooting though.... Good Luck

 

Hey see in your signature you have ordered marine injectors ??? not worth the $$$ until you do some other things 1st so if you don't have em yet you need to really look in other areas for performance 1st, the 6.5 injector requires the PCM to be chipped OBD-I or reflashed OBD-II 1st before you see any benefit in h/o injectors.