Well she's at it again. My 96 2500 has thrown brief fits since she was new. She"ll stall or fail to start but turn over just fine. She may restart immediatly or it may take a couple hours, but always before the tow truck arrives. There are no consistant codes after she's thrown a fit but over the years Mr Goodwrench has given me a couple IPs, 2 lift pumps and a glow plug controller as codes appeared. From your site I came to suspect the PMD but it has been replaced with the IP and I don't believe that covers all the symptoms so I'm hesitant to just spring for another new one.

Symptoms are: She don't run
The wait to start light doesn"t come on
Lift pump doesn't run
Service engine soon light will come on or flicker
Fuel pump relay will chatter
Power at the relay box seems normal
Usually no codes
Miraculously cures its self

Any suggestions for where to look for the problem would be appreciated. She's started doing it to my wife while hauling horses and she doesn't have nearly my sense of humor about it. Thank You

What's the DTC's it's throwing?

The intermittent glows suggest bad battery terminal connections or bad GP relay, that can't pull enough amps to cycle and so they shortcycle instead. Clean all (+)(-) connections and grounds.

Fuel supply might be resticted or OPs may have failed and LP doesn't pump during normal operation.

Sounds like your battery cables going bad (common with these trucks). Look there first.

I have done quick clean and tightening on cables...off now to give the terminals a good brushing. No obvious wear or damage to cables. Can crimps go bad or just worry about the connections?

What are DTCs?

Turns over well so I've suspected problem is down stream of battery cables. All symptoms-glow plugs and stalling happen and clear up together. Wondering if there is a common feed or controller for these that wouldn't affect other systems

Thanks for the replies

DTC's are the Diagnostic trouble codes the ECM stores and flashes the service engine soon (SES) light. Autozone will get the codes for you but you have to write them down to post on here for analysis.

GM cables harbor corrosion inside the sheath around the connector.

Yeapper Remove that rubber sheath while you have them off. Easier to clean and keep that way. Fer sure sounds like a loose connection somewhere, maybe a ground?

I have done quick clean and tightening on cables...off now to give the terminals a good brushing. No obvious wear or damage to cables. Can crimps go bad or just worry about the connections?

What are DTCs?

Turns over well so I've suspected problem is down stream of battery cables. All symptoms-glow plugs and stalling happen and clear up together. Wondering if there is a common feed or controller for these that wouldn't affect other systems

Thanks for the repliesIgnition switches will do that, they carry the GP and the IGN.

There usually are no codes after an episode. Most recent had a glow plug power supply code so replaced the GP relay-That was 2weeks and maybe 150 miles ago. It threw a fit on my wife Mon. evening and gave me the time to check all hot legs in the relay box while the fuel pump relay was chattering...all normal. Walked over and drove it home later that night. It ran fine yesterday and started but just sat today.

I like the ignition switch idea. I haven't looked at that and it does take a beating when it's doing its thing. Cause or effect?

Check out this post here
http://dieselplace.com/forum/showthread.php?t=11206
Mine doing similiar problems and it was looked by 4 different shops two of which were dealers with no fix that worked. I found a wire in engine compartment on bottom side of wire bundle coming from ECM was intermittantly shorting on the AC line. It would run very similiar because as the engine got warm and through vibrations would relax until it touched the AC line and stall, then as it cooled it would lift off the AC line and start and run again sometimes with codes sometimes without. Check the post and see if it helps any. I replaced lots of parts multiple time before I located the gremlin. Good luck

Thank you for the suggestions. I'm going to go get codes read this afternoon and see if that shows anything. She always runs real sweet if she runs at all.

Got a good independent mechanic who likes GM diesels (a rare thing) and is putting some thought to it. Will run your suggestions past him and maybe get him on the site.

Finally got to town for code reading -absolutly nothing showing. even checked the mechanics truck to make sure the box was working. Did lift the hood and yank on various bundles of wires to try to make her mad , but I guess it's spring and all is right with the world.

Is there a tidy way of hot wiring around the ignition switch to test that next time it acts up? That's a hole in my street education.

Thank You