?? about the new gray PMDs

[gnel]

How are these working? Do I need a new harness? Will my old heat sink work? Old resistors work? I´m on my last (of 5) PMDs. Thanks folks. gus

 

[gnel]

I found a thread from 2011 and now know I need a new harness + resistor. Nobody can give me an update on reliability? Thanks again g

 

[matuva]

You can re-use old harness and resistor as long as you grind the side ("ears") on both male plug & resistor.

The grey ones look almost reliable...

 

[Burning oil]

Grey = Stanadyne They are good units, but not any better than a Flight System PMD. Grey only has 6 month warranty and cost more. Flight Systems has one year warranty and cost less. No brainer.

 

[gnel]

Thanks.

 

[greenmeanh1]

Mine, an older rev 2 slightly modded has been on my IP going on 10 years without issue. Going through 5 is nuts and points to a potential IP fuel solenoid issue or as they say poppetitis!! Generaly caused by bad fuel agents contaminating the IP and siezing up the solenoid. P1216 P1217 are ussualy the codes that will follow in time along with 1000 bucks or so for the enevitable replacement of the IP. As you might imagine this puts a lot of stress on the PMD power transistors which are a pair of inverse mounted MJ15004g darlington emitter type transistors. The bells on these get hot under normal loads approaching 150- 170f. Even a small increase in amp loading can put these up to pooling temps for some solder types and in there lays one of the many issues. Couple that with those same temps or higher after vehicle shutdown and now the PMD is fighting 2 resistive based isssues from an electrical standpoint. I find i get the best run temps on the PMD mounted to the IP which is around 126f going down the road. That means fuel running through the IP is soaking up some of the heat. Problem is as soon as you shut down the underhood temps go through the roof. My measurements are based on a meat probe i use to poke around in varoius areas under the hood.

 

[great white]

Been running a DTech for nearly three years now.

No issues.

 

[Will L.]

greenmeanh1- the air flow and heat applied to our ip's is drastically lower than on the pickups, vans and suburbans. The ambient temp even on the gm-6 is about 100* lower than in a van. Is has to do with the open air flow under our hoods compared to the more stagnent air under truck and van design.

The possible fuel solenoid is an excellent call, gnel it might be worth the extra $ for the reduction of possible load. I remember a few people running them off a relay about 15 years ago to try reducing the load. I never saw the outcome of those experiments. I just cheated and run db2 and dont fight that fight, even on my pickups I had that I kept for a while, they got the ds4-db2 conversion. Its just so much more reliable, especially if the zombies learn how to set off a emp!
:thumbsup::rofl:

 

[Big T]

Gus, our wrecked '95 went through a couple PMDs Nd an IP until we mounted the PMD on a heat sink hung between the driver's side battery and headlight. I need to retrieve that for a spare before we scrap that truck.

 

[Burning oil]

Mine, an older rev 2 slightly modded has been on my IP going on 10 years without issue. Going through 5 is nuts and points to a potential IP fuel solenoid issue or as they say poppetitis!! Generaly caused by bad fuel agents contaminating the IP and siezing up the solenoid. P1216 P1217 are ussualy the codes that will follow in time along with 1000 bucks or so for the enevitable replacement of the IP. As you might imagine this puts a lot of stress on the PMD power transistors which are a pair of inverse mounted MJ15004g darlington emitter type transistors. The bells on these get hot under normal loads approaching 150- 170f. Even a small increase in amp loading can put these up to pooling temps for some solder types and in there lays one of the many issues. Couple that with those same temps or higher after vehicle shutdown and now the PMD is fighting 2 resistive based isssues from an electrical standpoint. I find i get the best run temps on the PMD mounted to the IP which is around 126f going down the road. That means fuel running through the IP is soaking up some of the heat. Problem is as soon as you shut down the underhood temps go through the roof. My measurements are based on a meat probe i use to poke around in varoius areas under the hood.

Add to that the temp swings in cold climates: go from say 20*f outside to underhood temps and you have a huge temp swing that may happen several times a day. We continue to monitor PMDs in real time both under hood and bumper mounted. Bumper mounted is allways cooler.

Been running a DTech for nearly three years now.

No issues.

FWIW Dtech is made by Flight Systems.

Its just so much more reliable, especially if the zombies learn how to set off a emp!
:thumbsup::rofl:

What do you do about the starter and "E" trans :rolleyes5:

 

[Will L.]

What do you do about the starter and "E" trans :rolleyes5:

I don't get your question. Starter? Nothing different in db2 vs d4. E trans- tps on db2 and tcm from 4wd feeds info to trans. If you have a oil pump drive on truck you just get ess oil pump drive and there you go. Put it in 4th and push the go pedal. Is that what what you are asking?

My hummer adding the gm-6 turbo gave me a hickup with out the use of ess oilpump drive, so the custom made crank sensor fixed that. Could have done it off the alternator pick up as well. I just wanted to go cps because i submerge my truck into rivers and mud so often. I heard of the external alt pick up system having problems when it is under water.

 

[ak diesel driver]

I think it was an EMP ? for you Will

 

[Burning oil]

I dont know what all an EMP would affect so I was asking about other electron activated devices. Think you might need a NV4500 and have to push start it??

 

[Will L.]

Emp thing was my crappy sense of humor, but since you ask...a spare stater in an enclosed metal box (ammo can) will keep it and tcm and little white box, (cant remember name right now) for tranny speed ratio, safe. That is also works as a glove box. (yes i am an idiot -it really is my glove box and houses my electronics mounted inbetween me and front passenger seat). Electronics inside tranny are safe, tranny case shields them.

The hmmwvs are outfited with an aluminum case around the tcm and white box for emp protection. Only certain ones were outfitted (idk why). They also have an ammo can mounted with starter, alternator & tool kit mounted in rear of truck above passanger rear wheel. Those rigs are also outfitted with gel filled batteries- i guess they do better in emp?

I have thought about nv4500 a few times for mine. All hummers/hmmwvs are auto tranny.

 

[Drago]

I wonder what it would take to make a PMD out of Vacuum tubes, I see the the two large power transistors but not to sure about the rest. Vac tubes would solve the EMP and heat issues

 

[Will L.]

One of the most common failures is the bad solder joints. Simply enlarging the unit to not make everything a micro solder could make that stout enough to withstand the abuse it see. One thing I've never seen as a collective group that simply listed what the cause was of the failed units. If someone doesn't know how, rather than stored in the trash, they could mail it off to someone who knows how to turn determine what the problem was. I realize there are companies who try to redesign the same unit-to go in the same location, and have the same dimensions. Drago I think is on to something big here. If you could make a new one that was half the size of the suitcase but you had to mount it behind your seat in the cab and he would never have a problem with it again -would that be worth the headache to you guys?

I know causes to be the big temperature swings or electronic messy signal but never heard it ruined this exact diode or cause problem Blah blah blah.

 

[gnel]

Alot of good ideas. Thanks again. Just one of the five was bought new. One came on the pump and I bought 3 from some guy on Ebay. We dont get much in the way of temp. swings here. It´s pretty much always hot. Maybe a bigger heat sink?

How would I test the fuel solenoid?

 

[greenmeanh1]

I wonder what it would take to make a PMD out of Vacuum tubes, I see the the two large power transistors but not to sure about the rest. Vac tubes would solve the EMP and heat issues

Neat idea with vac tubes. Maybe an old guitar amp would serve well. LOL
There is a bit going on inside the PMD beyonfd the 2 big power transistors. There a a few logic stages to deal with as the unit has a LM295 regulators, a CD401 flip flop, 3721 64M AF8L clock, S5230 PW1K nand plus a 14 pin comparitor of unknown origin. I have always believed the logic and high amp switching should be separate from each other. What they do is put the logic on one side of the PCB and the switching on the other side. I can see many problems with this design.

 

[greenmeanh1]

Much Better would be a servo type PWM motor controller that shares the frequency of output over dual transsitor chains and makes use of bipolar transistors as opposed to the darlington emitter type. This is a much larger package.