I have 135,000 miles on my truck and the circuit in the pump is fried. An aquantence of mine was discussing a swap from the electric pump to a mechanical pump with me about 2 years ago. I have lost touch and do not know what the final result was. He told me he had the mechanical pump in place but was having trouble with the shifting of his automatic. I have a manual. Is it possible to make this swap? His was non-turbo, mine is turbo (1998). Will this affect the computer? Just looking for a cheaper and more reliable alternative. If it is not possible, what and where is the cheapest/reliable replacement.

 

Pilgrim,

is your problem just the PMD, or are you talking more of the Solenoid? Cause if you get a new PMD and mount it to your bumper, you can avoid all of the pain and suffering by pulling and putting in a pump.

I have a 93 setup that has the manual pump, and I can the 95 setup that has the Electronic pump.

I can tell you that if you do the electronics right, the electronic pump is just as good as the manual.

Guipo

 

A few of my friends have been telling me the same thing. I beleive it is just the pump driver and I am going to order it with a heat sink and go that route. A Chevy dealership fixed it for me many moons ago under the service letter. It did not cost me anything. At the time, I asked the mechanic if I should relocate it and he assured me that the new driver would not do this again and that there was no need to relocate it. I should have done it anyway.

 

Pilgrim

There are 3-4 things that go out on these trucks all the time. PMD is easily movable. The OPS is another thing that goes out. Another thing is the Vacuum Boost controller. Other than that they are great trucks.

There's no way to test a PMD except try a new one. Try pensacola diesel. Thats where I got mine!

PM me and I'll tell you where to find some great info.

Guipo

 

if you got to change the pump it should only take about 4 to 5 hours at the most and thats working at a VERY moderate pace........

 

I mounted the PMD up on top of the intake manifold to a heat sink. I still had to use a short extension. The truck started right up and is running fine. It is agrivating, because I asked the mechanic 4 years ago that replaced it (for free) whether we should do that and the answer was that the new PMD's did have the problem the old ones did. Anyway, I got it up and running. Thank you all.

 

PMD's should ideally be placed outside of the engine bay. They actually have been known to get hotter mounted in the engine bay, or on a heat sync than attached to the Injector Pump. The reason is, the Injector pump uses diesel for cooling the PMD. While it wasnt ideal it did provide some cooling.

Another word to the wise, if this is the PMD that has failed you in the past, expect it to fail again, no matter where you mount it. The only way to know you have a good PMD is to get a new one.

Guipo

 

I am looking at buying a 1994 6.5 with 245,000 km. does this year have the mechanical pump, or the electronic one. And what else should I look out for.

 

X2

Turns out that the intake manifold heatsink mounting location is the worst possible place to put it.

The PMD will absorb more heat after engine shutdown in that location causing often times an earlier failure rate.

I would advise that you buy a quality 6' PMD extension harness and move the PMD/heatsink/resistor combo to under or behind the frt bumper or mounted to a core support in frt of the cooling stack behind the grill.

One point that I quoted above is worded a little funny for me though-PMD's MUST be mounted to an aluminum or copper heatsink.

 

from what I have read the 6' extension is the best option, mine is mounted behind the grill infront above the oil cooler, looks tidy and doesnt seem to get hot by the feel of it... not a good feeling when they start to play up in traffic!