engine stalls no wait to start light

[R.Roy]

1997 Burb 2500 stalls about ten minutes after startup or won't start at all. No wait to start light some times you can hear relays chattering ( the ac clutch will chatter if the defrost is on) then for no reason it will start working after you cycle the key. If you try to start with out the wait to start even when its warm it still won't start. Had a local diesel shop look at it and when it failed mechanic couldn't get scanner to talk to PCM but it did have power going to it. Replaced ignition switch year and a half ago, FSD and cooler year and a half ago also lift pump about the same time.(less than 15,000 miles ago). It seems to happen on colder mornings especially with a large temperature swing.(40*F). Cleaned and added new grounds also did the battery terminal updated. Did a wiggle test on harness and on pcm. Can't seem to find anything I'm about to throw a PCM at it but hate to spend money and have same problem. HELP!!! (also not giving any codes when this happens)

[gmctd]

Those symptoms indicate failing connections - power, ground, signal.

Something eluded you, or something occured after your previous checks.

Start at the battery terminals, both positive and negative - look for oxidation, corrosion, loose connection at both ends, incl starter connection.

Check the main harness grounds at the rear of the intake manifold, and the connections at the fuse block center.

Check the connections at the power block on the firewall.

Check the harness down by the evaporator low pressure line where it exits the firewall for frayed wiring.

Check all the main harness connectors behind the fuel filter, also the harnesses down to the transmission and lift pump.

Also check the connector to the ABS module - try pulling it, see if PCM recovers.

[More Power]

You could also probe the various ECM & ignition fuses with a multimeter to determine whether they have power - when this occurs.

Jim

[R.Roy]

Heres an update to were I'm at. Removed and cleaned all battery terminals, added a ground wire from passenger side battery to engine block second post from firewall on passengers side, also moved the pcm grounds (20awg black/white and tan/white) to same stud also continued same wire to chassie ground for the hood and continued to drivers side battery and attached it to frame on drivers side. Ceaned ground straps on passenger side. Removed and cleaned the feed for fuse block in engine compartment, also pulled fuse block out and inspected the underside. Checked the PCM grounds at pcm connector to chassis and had about 2 ohms. Cleaned all connectors on firewall (scraped pins with small screw driver). I check the power a the PCM after it stalled and had 12v between orange wires and pcm ground also checked pink wires and pcm ground. Wiggled wires to ignition switch and still no luck. Also removed wiring harness from firewall and inspected. The truck will stall randomly sometime just cycling key and it will restart and run fine, other times the fuel pump relay and AC relays will just chatter (while they were chattering wiggled power, grounds etc. ) then just stop and every thing is fine. Also pulled the PCM and removed covers, visual inspection of board nothing appears burnt loose etc.. Not really sure what gmctd is calling the power block on firewall. I've yet to check out the ABS stupid thing idled over an hour and wouldn't fault. Open to any suggestions (minus setting the POS on fire as my wife suggested). Thanks (sorry so long winded)

[Pault]

I am having the exact same problem with my 3500 sierra - exact problem. It has been in the shop twice for this, and I have spent around 1300 dollars on it. It will run fine for a couple of days, and then just quit and won't restart. After sitting around for a couple of days, it finally restarts, and runs fine for another hundred miles or so, and then the same thing.

I too appreciate all the responses to this question.

[65TD]

What parts have been changed?