PMD/FSD Photos

[paultex]

Read some posts about PMD schematic.I've put up a website with some shots of a PMD that I disassembled about a year ago. The pictures are about 70 k, but if you click on them you will get a 1.3 mg picture that you can blow up, if you have Vueprint or a program simular. Ths was one of about four units that failed on my truck.

WWW.oplnk.net/~vittelusa/pmd.html (http://WWW.oplnk.net/~vittelusa/pmd.html)

The original lasted 72,000 miles, the next three lasted 32,000, 17,000 and 8000, with a heatsink/cooler mounted on the intake manifold. I gave up on that, went back to the pump mount with new harrness. I have 27,000 on this at this time.

I have 195,000 miles on the truck. I tow a 9000 lb
trailer about 10000 miles a year.

Paultex

[HowieE]

How did you remove the potting compound? I can not determine how much of the distruction was from your removal and how much was failure related. Did the unit show signs of burning.

[paultex]

At the time I owned a CNC machine shop,(oil field).I retired last June. I machined most of the potting & chipped the rest. There were no signs of burning & the two transistors were OK.

The PMD was intermittant before I replaced it.

Paultex

[gmctd]

Excellent work, Paul - much better than my own, using heat.

Appears to have been some cold solder joints on some of the thru-board components, but could also have occured during the 'de-nuding' process.

Do you recall which of the three series this example is from, as I see some circuit differences from mine, 30214, from Sept 95.

Guy over on the Place has found a site offering a de-potting boil, appears to strip it clean with no damage, using a crock-pot.
His first attempt was with a blow torch - sure seemed surprised that there were components on the other side of the pcb.

[Barry Nave]

I agree with gmctd
the solder joint looks awfull :eek: even the "de-nuding" would not have caused this.
Remineds me of the soldering on the wiper board.
Could the fsd get this HOT :confused:
Don't think so :rolleyes:
What a story this could tell ;)

[markrinker]

Okay - dumb question time. What exactly does this troublesome little black box do? Why hasn't the aftermarket come up with a suitable replacement that will LAST?

[Barry Nave]

Mark
It's the FSD/pmd driver.
Now I'm sure you know about the black box tongue.gif
From the pedel to the IP the go in between would be the black box (FSD) that controls the IP fuel rate of flow as it works with the ECM.
Beta, the maker of the FSD Cooler has been working on an improved FSD driver.
Any know abouts on the new driver by Beta out there in members land?

[morgan]

Nice work Paultex. Glad somebody was able to finally do this. Hope we can learn something valuable from it.

Thank you for sharing your results with us!

[Marty Lau]

Beta has been very quite for most of a year. Why???????

[moondoggie]

Good Day!

It's possible that one reason no one has come up with a replacement is that when it fails, the engine quits, which can be hazardous to the health of the vehicle occupants. Offering a replacement part might require significant liability insurance.

Several years ago I bought a gas valve for the space heater in a camper we had. I don't know if it's true, but he said there was only one company making them, & most of the price was to cover the liability insurance.

Thanks so much for sharing this very good work.

Blessings!

Brian Johnson, #5044