Stalling, no start, no glow plugs and no power to engine

[twaddle]

Hi there,
For a long time I've had a very intermittent stalling and no start problem which would happen now and again but for weeks or months it would run fine.
Being so intermittent it has been difficult to diagnose but with the no start there was always no glow plug light and even with the engine hot it would not fire up indicating to me that there is no power to the glow and fuel injection system.
The PCM has been a major suspect so I purchased a good used Heath 250HP unit recently being sold privately on the DP.

This morning truck fires up OK, drives about 3 miles, stalls. No start for about 10 minutes. gets another 3 miles, stalls. 20 minutes later it decides to fire up. Gets about 2 miles. This time no start. Yipee, it's no longer an intermittent fault.
Gets towed back home as I've left the Heath PCM back at home.

Regards

Jim
Biggar, Scotland

Plugs in the Heath PCM engine fires up tries the original again, No start.
Installs the Heath PCM, fires right up.

So with a bit of luck my Loooong term stalling no start problem may be cured (dangerous thing to say) and it looks like it may be have been a faulty PCM.

[Robyn]

With a situation that you can replicate now I would say you have the little gremlin cornered.

Most lilkely a bad solder joint or possibly a cracked trace in the circuit board/s

These sort of things can be a real test of a mechanics mettle.

I had a similar situation with a 95 gasser Burb a few years back.
The sucker would run fine then backfire and loose power and finally quit.
Unfortunately it had to happen 1000 miles from home.
I finally got it into a chevy garage and their mechanics fooled with it for 3 hours and could find nothing.

Headed back out onto the freeway and within 3 miles it quit permanently.

Hmm on a hunch I hitchhiked back to town and bought a distributor and a couple tools and walked back out to the rig and stuffed the thing in.

Timed it by guess and off it went.
Got a couple codes so I fiddled with the distributor untill it quit doing that and got into a shop the next day and had it timed.

Old distributor was toast and the pickup coil was the issue, not to mention that the bearings were almost frozen and the shaft would hardly turn by hand.

Having had the thing in a Chevy garage with techs that had all the good scanners and such and used them they still could not find the intermitent issue.

Sometimes we just have to wait until its completely dead to find out why.

With the 6.5 when the issue is more than just stalling but has several issues all at once, wiring, plugs, grounds and of course the PCM come to mind.

Glad to hear your on top of it now.

Robyn ;0)

[twaddle]

Hi Robyn,
Over the last several years I've done the various improvements that have been mentioned on the Diesel Page and some of my own to improve the Battery cables and grounds along with the usual fuel lift pump, oil pressure switch and the FSD.
The very intermittent no start and no power to the glow plugs or fuel system (as soon as the glow plug light did not appear I would know the engine would not fire up)would only happen maybe twice a year and only the once each time then I'd get a spell of 3 or 4 stalls in a week then nothing for months. none of them for long enough to grab the little gremlin.
I even got a genuine GM manual shipped to Scotland and on studying the wiring diagram saw that the fuel injection system and the glow plug circuit were controlled from inside the dreaded PCM. I did suspect the PCM may be at fault but due to the intermittent nature of the fault I could not prove it.
Also adding to the fun was the fact that no codes ever showed to help point me in the right direction.
So when the second hand Heath PCM came up for sale I thought it may be handy and today it did come in handy.
Hopefully this has fixed the darn thing until something else goes on the old girl.

Jim
Biggar, Scotland