6.5L stalling? HELP!

[madcarson]

runs fine then out of blue it will cut out instantaniously,may not do it for days then all of sudden? I haven't chgd filter yet but will! could it be something serious or ?Only happens for split second then all is good ? Any help would be appreciated on where to start looking for problems!:eek:

[torque454]

So is it stalling or just cutting out ocassionally? Please elaborate.

[markmc]

Thats what mine was doing; very occasional erratic running, slight occasional kick, then finally it started occasionally cutting out altogether when the lift pump started going off. Replaced the lift pump, blead the system at the T handel on front of motor and all is well.

[madcarson]

yes it just cutsout like the ign.is turned off for split second:confused:

[torque454]

Maybe a sign of pmd failure in the near future? Mine has a slight jerk in it on hard throttle under load like pulling a trailer up a hill on the highway. It acts as tho it too momentarly shuts off for a fraction of a second but the tach never drops. Only happens under load. People seem to think it is fuel related too but my lift pump is new and the OPS is fine. Pump works as it should and all the air is out of the system. I dont really know what it is either the only other solution anyone can come up with is the fuel filter. I think your problem is different than mine tho, mine only happens under load out of OD at hard throttle when fuel consumption is at its highest. The way i understand it yours does it ocassionally, anytime. That leads me to believe it isnt fuel starvation, but more like fuel cutoff at random which could be PMD or perhaps a loose or dirty connection somewhere, or even worse, the IP wearing out.

[Oldsmoke]

My truck has now come down with the "sudden cut out" syndrome. Driving along fine and normal then suddenly will just cut out and die or sometimes just a hiccup like you'd turned the key on and off. When I pull over and turn the key off for a few seconds it will usually restart just fine but does seem to be getting worse. No SES light. If it does restart it seems to run fine and have full power.

[vail426]

Is the PMD still mounted on the IP?

[tdijetta99]

Maybe a sign of pmd failure in the near future? Mine has a slight jerk in it on hard throttle under load like pulling a trailer up a hill on the highway. It acts as tho it too momentarly shuts off for a fraction of a second but the tach never drops. Only happens under load. People seem to think it is fuel related too but my lift pump is new and the OPS is fine. Pump works as it should and all the air is out of the system. I dont really know what it is either the only other solution anyone can come up with is the fuel filter. I think your problem is different than mine tho, mine only happens under load out of OD at hard throttle when fuel consumption is at its highest. The way i understand it yours does it ocassionally, anytime. That leads me to believe it isnt fuel starvation, but more like fuel cutoff at random which could be PMD or perhaps a loose or dirty connection somewhere, or even worse, the IP wearing out.

Mine is doing exactly what yours is doing... It's been an issue since May when I picked the truck up.. It would occasionally "hiccup" under moderate throttle.. It got progressively worse over the last month or so to the point where it felt like a gasser with a bad set of wires.. Heavy throttle it didn't want to know me, let alone pull anything. Light throttle it was very smooth and quiet like normal, except for my fuel mileage going to crap... I changed the fuel filter to no avail.. lift pump has steady pressure throughout the rpm range, even when the truck was studdering... It also felt like it was down on power anyway compared to the few other 6.5's I've driven, so I picked up a new PMD and the FSD cooler and #9 resistor... The truck has a noticeable amount more power and the bad studdering is gone but I still get the "hiccup" once in a while along with a light studdering under heavy throttle in 2nd and 3rd gear..

94 Blazer 6.5TD, 4L80E.....

[dieseldog]

Pmd failure will cause erractic problems, change the position of the module on a heat sink onto the firewall or else where, if caught on the side of the road pour water on it to cool off, it won't hurt the electronics because its a "potted" device.

[Joe 94 dually]

I put mine in the front bumper w/ a heat sink slightly smaller than the FSD and, another one (about the size of that blue one they sell on Ebay for $60 or more) on the other side of the PMD just above the plug. It barely even gets warm now. Paid less than $8 w/ that blue thermal grease and longer ss bolts to mount everything together. Don't forget to get the PMD mounted tightly to the heat sink, that is what allows it to dissipate the heat properly. And use some dialectic grease in the connectors to keep moisture out.