I have been reading all that I can. I have a few questions. 1st. I've read that the PMD can't be tested to see if it is working properly. Yet, (I know) there are used ones being sold on Epay that say they are tested on a $50,000 bench tester. Seems hard to believe anyone can have 50g invested in a tester. Thoughts about this ebay vendor. Second, I see people mounting the pmd in the holes in the front of the bumper. Is there an issue with it being exposed to salt, H20 and everything else that can hit it up front. Even if unit itself is ok exposed, how about the connectors. I'm about to replace the pmd in my truck and i'm trying to decide what to do. The original unit has lasted 11years, 95,000 miles without failure in it's original location. If I remount a new one on the pump, what's the chances that this happens again?
Thoughts anyone?
Thanks
Juice

I have been reading all that I can. I have a few questions. 1st. I've read that the PMD can't be tested to see if it is working properly. Yet, (I know) there are used ones being sold on Epay that say they are tested on a $50,000 bench tester. Seems hard to believe anyone can have 50g invested in a tester. Thoughts about this ebay vendor. Second, I see people mounting the pmd in the holes in the front of the bumper. Is there an issue with it being exposed to salt, H20 and everything else that can hit it up front. Even if unit itself is ok exposed, how about the connectors. I'm about to replace the pmd in my truck and i'm trying to decide what to do. The original unit has lasted 11years, 95,000 miles without failure in it's original location. If I remount a new one on the pump, what's the chances that this happens again?
Thoughts anyone?
Thanks
Juice

As you have found, it is not possible to test a PMD, other than trying known good or trying the one in question on another truck. It's not in danger up front. The connector is also safe, as it's a weatherpak.

There is always a way to test electronic using electrical testing like resistance and voltage. Challenge is the PMD failed when it is hot and unless you can replicate that environment about 200F to 230F inside the engine.

PMD is like playing with Russian roulette. You are lucky yours last 11 years. Everything depends on the environment that it is in. There are people that last only a few months to like yours. If everybody last like yours then GM will not have a lot of trouble and can sell more 6.5. This truck is known for PMD trouble and we have a solution but GM never admits it. The good news is that it becomes very affordable because nobody wants it.

I think i'm going to relocate to bumper. Now, I was thinking about getting the cable from pmdcable.com that plugs into the new stanadyne. I know that I need a heat sink, and people have talked about making their own. Would a real big chunk of aluminum work. I have a crucible furnace, and can easily just melt some aluminum down into a little slab. Do I need the fins of a typical heat sink? How big or how much surface area is needed. Or should I just buy something.
Thanks

I purchaced a 94 in 1999. I had one replaced about 5 years ago on the manifold. I just replaced another one remote mounted behind the bumper. From everything I read heat will make them fail. I purchased it off of ebay and did the work myself. to mount one back in the original is alot of work.

I think i'm going to relocate to bumper. Now, I was thinking about getting the cable from pmdcable.com that plugs into the new stanadyne. I know that I need a heat sink, and people have talked about making their own. Would a real big chunk of aluminum work. I have a crucible furnace, and can easily just melt some aluminum down into a little slab. Do I need the fins of a typical heat sink? How big or how much surface area is needed. Or should I just buy something.
Thanks

Fins on heatsink are function to increase the surface without increasing the footprint of the heatsink. Heath puts it in a big area of flat aluminum. Also, the surface where it mounts need to be flat for contact. You can use ArcticSilver5, heat transfer compound used for CPU to facilitate heat conductivity.

00Juice,

I have the Heath PMD mounted in between the holes in the bumper. The aluminum plate is quite large and barely fits into the bumper from the rear. Without measuring, I'd say it is 8" by 14". I could measure it tomorrow if you like. It is also quite thick, nearly 1/4". In my opinion, you can't make the heat sink too large.

Jake

Thanks for the info. I just bought a setup on ebay with ext. cable, heat sink and PMD. When it shows up, I will be attempting to install. I'll let you know how it goes.
Thanks again everyone