1. Describe the problem you are having in detail: I've been having ever increasing drivability issues, and have taken steps listed here to "solve" them. Just when I think I've fixed it, it's back! Issue is, truck sometimes starts right up and drives, and unexplicably, shuts down and refuses to start. No WTS light, no lift pump function. ECM fuses have juice. Then, with no set series of events, WTS comes on, and it starts!

2. Year of truck/engine. 1997
3. Odometer reading (indicate miles or kilometers). 124,000 miles
4. Indicate the model number on the Injection pump Don't know, but it is electronic.
5.it’s a 2500
6. Do you have an EGR on the engine? F code
7. Air Filter condition brand new
8. Fuel filter condition freshly changed, and Racor 2micron setup installed
9. Location of PMD/FSD (http://www.dieselplace.com/forum/showthread.php?t=39436)? behind bumper
9a. remote mounted wiring harness purchased from Penscola diesel 9b. Indicate the location and condition of the FSD/IP grounding wire. can't find it
10. Outside Temperature 55F°

11. Service Engine Light while running?- intermittent
11a. Service Engine light doesn't glow during cranking. bulb check: Yes
12.Have you scanned for engine codes? No
12a. List exact results on engine codes (http://www.dieselplace.com/forum/dtc.php).

13. Condition of Battery terminals removed, cleaned and tightened.
14. Known condition and age of Batteries. about 3 years old
14a. Are batteries a matched set of same age? yes
15. Major Grounds (http://www.dieselplace.com/forum/showthread.php?t=157085) removed/replaced cleaned and tightened
16. Does engine crank, or "turn over"? yes
16a. Does engine start and run? sometimes
17. If engine does not start- Crack injector line (http://www.dieselplace.com/forum/showthread.php?p=2188140#post2188140): do you have fuel? Yes/No
18. Does your Wait To Start light come on? not always
18a.Number of seconds WTS light is lit about 9 seconds when it does come on
19. Engine Cranking speed (if you have an accurate tachometer). don't know

20. Are you experiencing Stalling? oh yes!!
20a. Describe the event. None specific
20b. Do you notice loss of dash or instruments? didn't notice
21. Check turbo inlet and air filter for obstructions.none
22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?
23. Lift pump test (http://dieselplace.com/forum/showthread.php?t=39350) - Describe results. replaced and it does work OPS mod done

24. Upon cold start, does the radiator hose get hard quickly? didn't check that
25. Upon cold start, do you have excessive white smoke? No
26. Do you have excessive cranking time before the engine starts? No
27. Have you used the block heater? NO Does it affect engine starting?
28. Are all glow plugs in proper working order (http://www.dieselplace.com/forum/showthread.php?t=39182)? yes

29. During hard acceleration, do you have excessive black smoke? No
30. Do you have any unusual exhaust smoke issues? no
31. Turbo check out (http://dieselplace.com/forum/showthread.php?t=39368) - Pass/Fail
32. Indicate fuel that you are using: #2 Diesel
32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system).N/A
33. Are you using any fuel additives? no
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? No
35. Do you have any service history available that might pertain to the problem you are having? PMD's replaced afew times, including a new FS one just now
36. Please indicate any modifications to the vehicle that might help us diagnose better. Remote start
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BTW, I REALLY thought I had it when I removed the passenger inner fender and found the body to frame ground strap frayed to almost nothing, PLUS the nut to firewall finger tight. I replaced that one and the block one with much heavier straps, but I did run the engine strap to the starter bolt , since the other side to the block seemed impossible to bolt to its original location. I don't think this would cause my issue.

Check the fuse, sounds like ECM-B fuse, may not be bad but change it anyway. Also, may be relay issue for the GP relay/controller?

Did you hook up the OPS relay mod properly, make sure the connection are all good.

I notice you have remote starter? will that cause things not to work?

JM, I disconnected the remote start a while ago. Would the GP relay cause the motor to shut down? I thought it only functioned upon start-up. thanks for help!

Sounds like a bad ground,did you check the grounds back on the pass side head.
Could be ign switch going funky too

Bison, cleaned those grounds, and all others, I think, and replaced the ignition switch when, I thought, "its the only thing left"! Arrgghh!! thanks for replying

9a. remote mounted wiring harness purchased from Penscola diesel 9b. Indicate the location and condition of the FSD/IP grounding wire. can't find it

There should be a black ground wire attached to one of the torx screws on the top of the injection pump. This wire comes out of the wire loom/connector that orginally plugged into the PMD on the IP. Make sure that wire is grounded to the IP. Not haveing that wire grounded to the IP can cause problems.

Yea i believe its frustrating trying to find that gremlin.
what about the ECM connectors,did you look at them.?
ECM itself maybe?
Or its got to be a broke/loose wire or connection some where.

Also make sure that the battery connection is good. There are cases in the past where the battery connection was not good and caused electrical gremlins. In my case, my battery cables was badly corroded inside the jacket.

In other words, never forget the obvious.

I'll be trying all these (replace ECM last!) today. Hope I get it. Most frustrating part is just when I really think I found the problem, WHAM! its back! Thanks for the input, guys. Incidentally, I recall the problem really started over a year ago, in a snowstorm, when I went to start truck (at work) and the WTS light didn't come on, and it wouldn't start. Took a train home, next day, I went to start it, and the light came on, and it started like normal. Hmm?

This information goes back to post #3, the GP relay/controller?

OK, today I found something of importance, but i don't know where to go with it. I had test lights on the OPS relay mod relay. Power to both signal leads, lift pump runs, truck runs fine. Suddenly, both signal leads lose power, and truck instantly stalls. Lift pump is not operating. I jump out lift pump at that jumper terminal, and the relay powers back up, and the truck starts. Even though I did the OPS relay mod, could the switch itself be the culprit? But then, wouldn't the truck sputter and die out, running out of fuel? It shuts off instantly.

anybody have a wiring schematic that includes the OPS? Or know if a modded OPS switch would still shut down the pump while driving? Tired of throwing parts at this now, and putting all my spare time into solving this.

New OPS with an extension hose, changed relay in the OPS rely mod, and its STILL cutting off intermittently! I wired up indicator lights to the posts on the relay mod into the truck, and they both shut and the truck shuts down immediately. I jump the lift pump, and after a short bit, it starts up again. A GM tech suggested I replace the computer. Yeah, its one of the last things I would need to replace, since I've replaced just about everything else!! But this thing is getting pricy, and even after owning the truck 10 years, I'd love to hold on to it, but it's getting to be pointless. Anyway, any thoughts on the computer going bad? Is this yet another problem area for these trucks? Thanks!