well im going to start with symptoms of these crappy pmds i was always under the influence that these pmds were either not working at all or that they would run for a bit till they were hot and then quit but i have fallen on a symptom that i never heard of on any of these forums and it happened to my sons truck basicly it went into an overspeed situation where he was driving and the throttle seemed to have stuck wide open he managed to get stopped and from then on it would just revv up when started to like 3000 rpms and then just about die then catch again and revv up to 3000 again and would just keep doing this till you turned the key off absolutely no throttle response with the accelerator pedal i was thinking it was the potentiometer in the throttle pedal but i was wrong tried a new one talked to several mechs out there and all thought for sure it was the inj pump something stuck wide open in there weather it be electrical or mechanical so i put in a new pump to no avail silly me guess i shoulda tried a pmd cause that was the problem all along but the symptoms werent at all like the norm for this pmd failure so i just thought i would jot this down for some other poor sap that is havin the same issue leigh

 

yes PMD can do many funny thing when there on there way out

Hope you put the new one in the front bumper on heat sink it will last longer

 

Hi all. I had a similar problem. I was cruising down the highway today when my truck/RPM's surged, a big plume of black smoke billowed out, and then the truck stalled. After drifting off the side of the road. I tried starting it, and NOTHING... After contacting a friend to come tow me (about 30min later), I tried the truck again and it fired right up. I made it about 5 miles before another huge surge in power/rpm, more smoke and truck stall. A few seconds later, it started up again ran for a minute, surged again, billowed smoke and died.... Eventually, I just had my buddy tow me home.

Recap of symptoms:
1-Surge in RPM
2-Plume of black smoke (followed by some blue)
3-Truck abruptly stalls (but turns over just fine)
4-May or may not start again.

Question 1: I have 115,000 miles on my 1997 6.5L pickup. It has the original PMD still mounted over the intake manifold. Is this likely a PMD failure??

Question 2: If I need to replace the PMD, does anyone recommend the Heath relocation PMD and relocation kit for $550??

I'd appreciate your input. Thanks.

 

It sound like bad PMD what on you are saying

Yes i would recommend Heath PMD , think he warranty them for 7 yrs and he will stand behind it just gave call talk to him very nice guy

 

I have a 1997 C3500 extended cab 4x4 dually. It has a 6.5L td with an F vin. I'm just struggling to figure out if it is a fuel problem (air in fuel) or a PMD or something else all together. I have very little experience with diesels, and the "surge" before the stall seems unique to most of the forums I have read through.

 

if you want check for air put clean fuel line on the return line on the IP see if you have air bubbles

To check see if the LP working just turn the key to run go to T-Stat housing and open the T-valve at the housing see if you getting fuel

Next thing i do is check all grounds and clean and repair if needed you fine 2or 3 wires at the back right of motor on intake then you have 2 ground straps right under the a/c dryer on firewall one goes to back head and the other goes to frame then you have ground on top IP that one for PMD one ground right fender at battery

I have seen PMD do the surging thing but befor say bad PMD have spend lot $$ do the thing i said above

 

Thanks. That is great advice. I also have a bad vacuum pump w/ absolutely no tubo boost as a result. Would you recommend replacing the pump, or switching to something like a turbo-master from Heath? It doesn't seem like a big price difference.

 

well you don't want put TM on or less you have boost and egt guages are sure vacuum pump is bad and just not leak in lines or wastgate sol that mounted on left valve cover

but if vacuum pump is bad and have the gauge it cheaper put tm on i would just build your own

 

I do have a boost and exhaust gauge. I'm 95% sure its my pump that is bad. I have less than 1" vacuum at the inlet and outlet of the waste gate solenoid. Plus, after removing the belt and spinning the pump freely, it knocks with every rotation.