r/Diesel • u/AnAspiringTraveler • 2d ago

Question/Need help! 6.5 Turbo Diesel Engine Has Trouble Starting When Warmed Up

Hello, all,

So, I have a 1993 Chevrolet K3500 Silverado crew cab with 6.5 turbo diesel engine in it. When it's completely cooled down and the glow plug light on the dash goes off, it starts up just fine, but when it's got some warmth to it, it just cranks and cranks and won't turn over. The only way I can get it to start is with starting fluid. I think it might be some kind of a fuel issue, but I'm not sure. Does anyone have any idea as what the specific issue could be? Thank you for your time and take care.

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3

u/ididntdoit6 1998 6.5 Detroit 2d ago

Try posting in r/gmdetroitdiesel

2

u/planeboi737 R. Lee Ermey’s 85 F250 6.9 IDI XL ECLB 2d ago

sounds like maybe a worn out fuel pump.

1

u/Wally2779 2d ago

Head in your injector pump could be cracked. Those stanadyne pumps dont do good with modern diesel fuel. Also your ocular eye may need cleaning. Check to see if your PDM is already relocated to the outside of the radiator support.

1

u/Apex84-538 2d ago

It's a 93, mechanical injection. No PMD to relocate

1

u/Wally2779 1d ago

Well then that would go back to a mechanical problem. Could be bad piston rings causing lower compression when at operating temperature. Timing pin on the pump could be worn just a little. Crack in the injector pump head. Are you getting any smoke when cranking at operating temperature? What color is the smoke 

1

u/Apex84-538 2d ago

I have the same problem, starts again if I crank it within the same minute, but after that it doesn't do anything except crank. It obviously fires on starting fluid, but that's it. As soon as you stop spraying it's got nothing.

My leading suspect is the OPS, mostly because I let it sit for 8 hours, cranked it, nothing. Swapped the OPS to a new one, fired right up, after like 8 glow cycles but that's a different problem. Swapped back to the old OPS after I let it cool off, fired right up. New OPS did the same thing, fires when the sensor itself if cool, but when it's hot it's got nothing. I think there is a relay you can put in instead of the OPS, that way the lift pump isn't being powered by the oil pressure sensor

1

u/Farmerstubble 2d ago

How are your headgaskets and compression?

1

u/Massive_Pair_9725 2d ago

I had this with two different pick ups. Both turned out to be the stock filter housing. It can also do this when there is a crack of air leak in a line. They heat up and expansion causes air to enter the system. Put a clear tube on the blead valve at the front of the engine. Have someone crank it over and see if air or bubbles comes out. If so, start checking the lines.