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View Full Version : PMD-Lost Cause


RAYMONDK
12-13-2006, 11:27 PM
I have searched diligently and can find nothing to indicate that GM has done anything to patch up the PMD mess. My wife is worried that our 96 3500 Dually will quit with her three horses in our trailer in the mountains. We're on our third PMD in four years. So far we've been lucky that we were not in a precarious position when it quits. My old 6.2 hasn't missed a lick in over 10 years (since I replaced the weight cage). over 90,000 miles. I find it hard to believe that GM can even get by with the liability. They recall for every imaginable inconsequential defect, How about the damn thing quitting without warning. Seems the NTSB would have done something by now. Would a class action suit not be in order? I know GM doesn't own Stanadyne, but they have allowed them to trash every diesel they ever made. Seems somebody up there would wise up and find another manufacturer for their pumps. I have not heard of any other injection system manufacturer with such a history of crap. I know a Bosch pump would cost more up front but the staggering number of GM diesel failures should be enough to more than offset it. I would reluctantly buy a new pump if I could be reassured it wouldn't quit.
The problem begins with the idea of placing a bunch of unhappy electrons in full control of fuel delivery. I have worked with similar fuel controls on large (1000 HP) boilers, but I only allowed the electrons to trim the fuel not control it completely; so that if the electrons became too un-happy the boilers would still run , just not at the ideal mixture. I would have been fired instantly if that fire ever went out.
What about a hot backup as is now commonly done in manufacturing. Maybe it would only provide a limp mode but at least enough power to steer and stop the beast. I would be real pissed and sue diligently if I or mine was to suffer dammage as a result of someones engine quitting from a problem known for years to exist. I know a bunch of enterpreneurs are making loads of money with retrofix-it kits but that has only prolonged the development of a permanent fix from GM that we are due.

Scrufdog
12-15-2006, 01:03 AM
The closest thing your gonna find to a permanant fix is remote mounting it on a nice heatsink. Some people say under the hood is fine, some say out of the engine compartment is better. I mounted mine out of the engine compartment to avoid heatsoak after the engine is turned off.

Snakeyes
12-15-2006, 06:03 PM
A large number of 6.5TD H1 owners have solved PMD problems by relocating their PMD's to locations with better airflow. Exactly as Scrufdog has posted.

94sub
12-15-2006, 10:54 PM
The PMD workd like a charm. Walt really knows his stuff. 255K and counting.

gregie998
02-19-2007, 07:33 AM
in replacing the pmd with walts, I've read good results from everyone, but whats the time frame? Like raymondk, we are on our fourth pmd, forth one aftermarket, he's changed his three times in four years........if i change out again, will i see two years, or three, or maybe this happens every year. I've been a diehard gm guy for years, but i ask the same question as raymondk.............great website anyway.....late for work, cya next friday..

TedReminder
02-19-2007, 08:16 AM
The early PMDs would quit without warning, I understand. The 34264 PMD was supposed to be better. Then the latest PMD#34583 is reported to die a slow death giving us time to replace it when it shows signs of dying.
I bought my 94 two years ago with 160,000 on it and now have 265,000. Same PMD that it had when I got it, a # 34583 mounted on the IP. I have another one mounted on a very big heat sink for replacement and another in the glove box for emergency. Maybe being prepared has warded off the PMD demons, maybe I'm just getting lucky.
I replaced the IP about a year and a half ago with one I got on ebay for $65 including shipping (lucky there too) Put the PMD on the pump with Dow heat sink compound. I tightened the transistor nuts before mounting.
I'm thinking that a couple things promote long PMD life. One is a good running lift pump to keep the fuel cooler running through the IP, another would be good heat sink compound along with properly torqued mounting screws. Oh, luck hepls too, I guess..
Ted