6.5 diesel help

Anonymous-0 · Jun 21, 2009

I have a 1996 GMC 3500 with a 6.5 diesel engine. I can be tooling down the road when the engine stops dead, it will not restart until the "WAIT" light comes on. I have replaced the PMD and have taken it out of the valley to a cooler place. I have replaced the glow plug controller/relay. The problem still happens. The check engine light never has come on when this happens and with my scaner shows no stored codes. I have been told I could have a bad EMC. What do you 6.5 experts think?

Bob · Jun 21, 2009

Are you saying when it stalls and you cycle the key to "OFF", then to "ON" the "WAIT" (GP) light DOESN'T come on if it's in "fail to start" mode? The GP's should ALWAYS come on, at least for a short duration every time the key is cycled "ON".

If they don't, I would suspect a wiring/connector problem, and lastly the ECM, as the controller is dumb (just a relay) and the actual GP timing and control is in the ECM.

Check ALL the battery cables and connections as well as engine-to-chassis-to-frame-to-battery grounds as well as the connectors/wiring at the rear of the engine and the wires at the ECM.

Have you been to "TheDieselPage.com", a GREAT resource for owners of the 6.5TD's?

Anonymous-0 · Jun 21, 2009

That's right when it stalls turn the key to on and no GP. Keep trying and until you turn the key to on and when the GP lights up it will start. This could take 10 to 30 minutes. All the other lights on the dash will light up when this happens.
Thanks

Bob · Jun 21, 2009

So, you must have bad power wiring to/from the ignition switch or a bad ignition switch.

bison · Jun 21, 2009

like bob said, most likely ignition switch,Shake the harnass under the steering collum when in a no start position.

Brandon Frazier · Jun 21, 2009

I have seen intermitent problems like this over and over with the 6.5"s and almost always it turns out to be the Stanadyne injector driver module.

justanothercase · Jun 21, 2009

i had that trouble with my 6.5. i put a manual inj. pump in with no electrics. remodeled the pedal since i had an automatic, you have to keep the Throttle position sensor on the base. i put the other rod on the opposite side in a slide on the base. everything worked perfect except i had to add a selenoid for the glow plugs and put it on a toggle and add a light so i knew they were on(didnt have to cycle them everytime then either when it was already warm). its fairly simple to do use your immagination on that pedal rod, id take a picture if i still had the pickup.

good luck with whatever you do with it

bison · Jun 21, 2009

his intermittend (no glow no dashlight) is NOT PMD related,but points to the ignition switch.I gt 4 of these 6.5 trucks,and know them well by now, as i do all the repairs myself.

Bob · Jun 23, 2009

Since the glow plugs don't come on when it fails, there's MORE to it than a PMD failure, likely a switch or wiring harness problem.

6.5 diesel help

Anonymous-0

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Anonymous-0

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Bob

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bison

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Brandon Frazier

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justanothercase

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bison

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Bob

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