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Hello all,
Im having a stalling problem with my truck only when cold, below 40 deg. Let me give you a little history on this truck. I have owned it for a year and 4 mounts, I got down in Texas. It's a 1998 K3500 crew cab long bed 136,000 miles singel rear wheel. The first stalling problem I found was the engine harness had rubbed through and was grounding out on the high pressure A/C line, right where it comes out of thr fire wall, passanger side. But when it got cold last winter, when you key up the glow plug light comes on like it should, and you can hear the lift pump working, starts right up and then stall's after about 5 min, or I'll get about 3 milles away. When you go to restart there is no glow plug cycle and no fuel pump cycle. I would have to wait anywhere between 5 min to 40 min and then I get the glow plug and fuel pump cycle and the it start right up, a little loud a first ( 2 sec ) and then sounds normal. Then the PCM failed, replaced it with a new GM PCM. But I was still having stalling problems only when cold out. I did find some weak pins for thr ECM-1 and ECM-B min fuse in the under hood relay/fues box, I also found weak pins on the relays, fuel pump/starter. I went through and replaced all of the pins with new packerd pins. I also replaced the glow plug controler,both negative battery cables,and both battery's and alt,and the ground ring terminals on the back of the passanger side head. I also replaced the Ignition switch, Still the same thing stalling when cold. When spring came the stalling went away. Now I got a check engine light for the optical/fuel temperature sensor, but no stalling since it has been warm. Now that it is winter, started stalling again after cold start's. So I through the book at it, New Injection pump (not rebuilt) New FSD on a cooler with ext harness, had injectors tested, new glow plug harness, glow plugs, injection pump harness, timing chain set, crank sensor, coolant temp sensor, map sensor, aircharge temp sensor, boost solenoid, lift pump, fuel filter, injector return lines.I also changed all the pins on the PCM, some of them had weak pins. Got the truck up and runing, no problems. One week went by and guess what, started it up one morning and it stalled after about 5 min of runing. Went to restart and the glow plug cycle was working and it started right up. It has done this a couple of other times to, and has restarted. A couple of days ago I went to leave work and about 5 miles away while driving it stalled. Pulled over and tryed to start but again, no glow plug cycle, I sat there for about 20min and finally the glow plug cycle came on and it started right up. I am sorry for the long post but Im trying to give you guys as much details as posable on this little DEVIL in my truck, THIS THING IS KILLING ME. Thank you for any Input on this,

Randy
 

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Seems you have covered everything. I would go back through the wiring with a fine tooth comb and check the grounds also.

You might have a bit of bad fuel maybe...or gelling?

Someone will chime in with more ideas. Good luck and keep us posted.

Also, write your truck info into your sig.
 

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I've had your problem...

Read about your problem with stalling in cold weather, recognizing everything.
Think:
There's one, just one thing that glow plug system and lift pump has in common: The PCM.
Something's wrong with your PCM, for sure.
Yes, I read you changed it. But are you sure you got a new one, or was it rebuilt?
My -96 Suburban 6,5TD stalled like yours after running just about 35' miles.
Car dealer changed PMD and fuel pump on guarantee, wich only gave me worse fuel mileage.
Finally, I found a guy who was clever enough to use his brain, he gave me the clue about one thing in common: PCM.
The problem was a bad connection somewhere in that PCM. After 5-10 min's of idling, it stalled, because the PCM started to get warmer. As everything changes size when temp changes, suddenly somewhere in the PCM a connection got lost. If I waited for half an hour, the car would start again. This problem got worse by the time. Second winter with the same problem, engine finally gave up, refusing to start at all. After changing PCM, it never happened again.
I suggest you try to borrow a working PCM somewhere. Maybe you got a bad one when you bought what you thought was a new one.
/Janne
 

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There is also a ground wire above the PCM connected to the firewall, pull your glove box and check that one out too. :)
 

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I just changed my pcm 2 nights ago due to the same exact symptoms that you have described: stalling, no glow plug light, no lift pump. I too have replaced ignition switch, grounds, batteries, oil pressure switch, pmd and more.

You're losing power at the pcm. Most likely, it's the pcm itself. The one that was in my truck was "remanufactured". That means that it was tested indoors at 68 deg F and tested okay. They most likely did nothing to "remanufacture" it or at least failed to discover what is an intermittent problem and is sensitive to cooler temps and humidity.

When the truck stalls, you've still got power to ecm-1 and ecm-b fuses, right? This rules out ignition switch. You should also still have power at the other end of those wires at the pcm plug (sorry, I don't know which pin #s they are.

Another thing to check and clean up grounds G-104 (this is the second head bolt from the fire wall on the pass side), the ground at the tranny dip stick tube (this is where your pcm grounds to the block). You should also verify that the braided ground wire at this same location is connected to the frame and is in good condition. I would also recommend adding another ground from the drivers side battery to the engine with another strap going to the body and one to the frame (3 way ground). This will rule out grounds for sure.


A way to check the continuity of the pcm ground wires is to see if they will support a load. This can be done by powering a standard reverse light bulb and seeing if each GROUND wire will support the load. Be sure that you're plugged into the right pin!

With all the above said, I say that your pcm is highly suspect.
 

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So that's what finally fixed the stalling for you Joispoi?
 

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guybb3, I've said yes every time you've asked me that question. It's really tempting to say it again. As it's been less than 48 hrs with the new pcm, it's a little early to make any final conclusions.

The new pcm looks like a brand new unit, whereas the one I pulled out was labeled "remanufactured", which happens to be an old Indian word for "many problems".

Anyway, it looks like the stalling is fixed, but now the new pcm has introduced a new problem to me....surging at wot and heavy accelleration:eek:fftopic: .
 

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Cheapy checks first off.

I know that you've been through just about every cotton picking thing on this rig, but you may be blind to something by now, just by the nature of troubleshooting. I know, because from doing troubleshooting everyday on equipment, there are times you've just got to get a fresh set of eyes on the problem.

Go over diagnostic checklist, and see what is left. The under 40° thing has me intrigued for sure. So here's a few more questions for ya:

1. What type of fuel are burning? #2 from the pump, or fuel oil, #1 or what?
2. Is your fuel filter heater working?
3. Is there a way that you can "rig up" a way to watch your IP incoming fuel pressure? I'd venture to say, that it will be dipping far into a vacuum just before the engine dies. Just a hunch.

DO NOT REPLACE THE ECM. Wait until you've done ALL OTHER DIAGNOSTICS FIRST! I have done this before with other electronics, and seen same results. This happened to me on a heater I was working on last year. The manufacturer could not explain it to me either, so they condemned the board, and said try another. I disagreed, but they said they'd foot the bill. They were dead wrong. It was another component in the system that was causing the issue. Long story on that, but anyway....
 

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OPS is never mentioned. Fuel supply pressure is likely.
 
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