95 GMC 6.5 runs for 10 sec. then stalls and wont start
 

My truck wiill start and run perfect for about 10 seconds then stall , and it wont start till it sits for a while. It started a couple weeks ago, it would run fine, then stall. sometimes it would run good for a couple days, then start stalling, usually it would start right back up. I changed the fuel filter, put a different (used) lift pump on, cleaned grounds, recently replaced the PMD, and relocated it to the bumper, new OPS. Injector pump is about 2 years old OEM. Batteries tested good, I can hear the lift pump running when I turn the key on, but it sounds different. I am getting fuel to the filter when cranking. Im starting to think I should do the Cummins conversion. Any and all help with this problem would be greatly appreciated. thanks in advance

You might consider the lift pump relay as part of the problem. If its coil is weak or its points burned or corroded you will get erratic operation. The relay in my '94 td is only in use during the starting cycle but I believe the relay in the '95+ is closed at all times. It's about a $20 part at O'Reilly.

first thing start with is OSP and LP test

it sound like bad PMD

you said you clean grounds was that just battery ground if so you miss alot at back right of engine their are more ground and straps make sure they are clean and good make sure the straps going from and to the firewall and to the frame and are in good shape

If you want do cummins that just wast of money going cost you you most likey fine d-max for what going cost you put cuimmins in

I cleaned the the grounds at back of intake,straps, and battery. Any others I need to be checking? How is the lp grounded? I also noticed I can hear something Buzzing in the dash, not sure that its related though.

there should be ground wire on top of the pump for the PMD

Could be bad PMD


Just because hear LP running doesn't mean it working right i would put 12v right to it and see if you get fuel out at water drain hose

If the lift pump relay coil is weak, when it tries to run the pump (which draws a lot of current) the points in the coil will open and close rapidly causing the humming sound you hear decreasing the current to the pump and decreasing, if not stopping the pump, intermitantly, decreasing the fuel flow. The relay can be tested if you don't want to replace it.

I ordered a new LP relay today, should be in tomorrow, I'll let you know how I make out.

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I installed a new LP relay today , still the same . Runs for a few seconds then shuts off and wont start for about 10-20 minutes. I have a new PMD ordered for tomorrow. Hopefully that will do it.

Sorry to hear the relay didn't solve your prob. What kind of temperatures are you having in central PA when you start your truck?

Its getting into the high teens at night. I keep my truck in a heated garage. But now that you mentioned it, I left my truck outside one night and it wouldnt start in the morning, it was a very cold morning(6degrees). I think I may have a bad GP or 2. Would this make my truck act like this?

ya it could if your glow plugs not working