please explain pmd 3 ?s

[shane]

everone talks of moving the pmd if i understand corectly it is to keep it cool
if that is the case why is it neccecery to keep it cool

what does the pmd do and where is it located on my 95 6.5 stock

i have looked at one on ebay some talk of a 6ft extention being found their which i did not find but what i saw was just a black box that looked to be about 4in by 4in if this is what im am looking for than please let me know if not could some one post a picture or let me know a good place to find pictures of these parts that are talked about in these forums so that i can stop scratching my head when i cant figure it out

ps.. this is a realy cool place to learn my truck is setting at the michanics right now and i am sick of paying someone else to tell me what is wrong
;);)THANKS HAPPY NEW YEAR TO ALL:):)

[Hubert]

PMD = pump mounted driver. Stock its a little black box on the left side of the IP. Original equipment is made by Stanadyne.

It controls the fuel solenoid that meters the fuel to the injectors. It is a pretty fast signal and control circuit and the electronic nature builds up heat like a motherboard on a computer.

Original design was for it to be mounted to the injection pump and have the flow of diesel fuel cool it. The IP in general uses diesel fuel as a cooling source and returns excess fuel that it doesn't inject to the tank. So it works ok when operating. However, when you shut off the truck diesel fuel quits circulating and the valley of the engine heat soaks the PMD. The thermal cycles of hot and cold on the side of the IP fatigues some of the connections.

Many people have remote mounted it on a heat sink with better longevity than the IP mount. The quality and size of heat sink and location is important to performance. When people remote mount it they call it an FSD = fuel solenoid driver.

You can find some stuff on EBAY but until you learn whats what I would do business with site vendors or other reputable sources. Some Ebay stuff can be of poor quality and design. For example: someone put a boat duct fan cooler for the FSD remote mount and thats not an accepted solution.

[Robyn]

Howdy

As Hubert stated the PMD is the little black box on the LH side of the IP.
This box converts very small electrical signals to a much more powerful signal that runs the fuel solenoid in the IP.

The PMD is mainly two very large power transistors and the more throttle that is applied the more heat they make.
The temperature of the PMD varies by work load on the engine as well as ambient temp and the heat of the engine bay.

During hot weather with the engine running the temperture down in the engine valley gets very hot and as has been mentioned when the engine is switched off the heat level rises a bunch.

The reason it needs to be moved
***** Electronics do not like high levels of heat at all and under such conditions they can and do fail. Your high powered computer has at least two fans and maybe more to keep vital electronics cool. Same need here***********

Removing a PMD from the IP is not an easy thing to do without first removing the IP.
I do not suggest this route but instead just leave the old one there and remote mount a fresh one.

The cable to the PMD can be dislodged from the PMD with the use of a thin screwdriver to pry the retaining clip out and then a little iggle and uggle to slide the cable back and then fish it up and out of the hole.

The PMD also has a little resistor that slides into the plug cavity and must be replaced into the new PMD. Its almost impossible to fetch the old one out of the PMD on the pump so the best deal is to use a fresh one with the new PMD.
These resistors are numbered from 1-9 and are used as a calibration device. If you use a small mirror and a light you may be able to see what was in the old one but gnerally if one does not know you can do fine with a Number 5

The resistor will only slide into the plug port one way as it is made to shape. It fits over the pins and has contacts on two of them. Just drop it in and work it down easily from side to side until its seated at the bottom of the plug port.
From here its an easy chore to mount the PMD and route the cable.
DO NOT move the ground wire from the IP (thin Black wire on top of IP)



Here is an ebay auction number. It ends on the 3rd Item number: 270199164757

I have one of these on one of my trucks and another one waiting for my dually

As far as the cooler goes pick one that is fairly robust looking.
Mount the little beast somewhere outside the engine bay (Grill area, front bumper nostril or as one member has done on a protected spot on his winch bumper) One of our advertisers prefers a spot behind the LH battery on the header support.

Cooler is better is the most honest thing I can say. :)


The main thing is get it to a cool spot with free flowing ambient air and also in a place that it is protected from a lot of weather and of course damage by external forces encountered in driving (brush bustin):D

I prefer to use a spot that I can get to if it does need changing out on the road. :eek:

DTECH makes a replacement unit for the PMD. I am personally running one on my dually. The DTECH has not been around all that long but the reports sound encouraging so far.
Local pump shop has been selling them now for about a year and has had zero comebacks. "WE SHALL SEE"

Be sure to use a good heat sink Paste between the PMD and the cooler and be sure the cooler is flat where the PMD bolts on. DO NOT suck the PMD down onto a warped surface. This may damage the unit as well as compromise the ability of heat to transfer.

OH BTW, heat sink paste can be found at almost any computer shop that sells Mother boards and processors. Its a white greasy looking stuff.
The PMD comes with a thin gasket thing that is supposed to go between the cooler and the PMD but IMHO the paste is better.

As far a pix go, drop into ebay and look at the harness.
You should be aware that there are sellers on ebay selling used PMD's
Be careful here as many PMD's may check good but not work once they get hot.There will also be pix of PMDs here too.

Its black and about the size of a deck of cards. It has a plug in on one side and 4 small holes in the face of it and is smooth with two oval openings on the contact side.

The coolers and harness stuff is pretty much a no brainer and most that I have seen from the sellers at ebay seem to be fine.

The companies that advertise here at the Page also offer such items too, you do have a choice of where to buy. :)

Prices on the cables seem to be about the same with most suppliers.
Pmds can get pricey depending on who is selling them.

I paid $279 for the Dtech at the local pump shop.

Best to you

Robyn

[shane]

thank to both of you for the very detailed info i will look at ebay a see what else i can learn once i figure it all out ill post and let you know what ive done

on another note is there a performance and or horsepower chip that i can buy for a good boost?

[More Power]

You can learn all about the FSD/PMD here:
http://www.thedieselpage.com/reviews/FSDCooler.htm

At the above link, you'll learn what it is, where it is located, what it does, how it does it, and why it sometimes fails. There is also a detailed discussion about how to improve its reliability. In the end, what aftermarket cooler you decide on is your choice (choices are all over the web), but the above page is the best source of information that answers the important questions. :)

Jim

[Cowracer]

While buying a Relocation kit is the easiest way to do it, its far from the least expensive. I built mine out of an old audio amp heat sink, some high quality wire, and about an hours time.

Total investment is around $11. If you have the $$$ then I highly recommend buying a complete kit from a reputable vendor, but if money is tight, please dont let that stop you from moving the FSD off of the pump and away from the heat.

Tim