Dtech FSD failure...

[arveetek]

.... after 6 years! :D

Yup. I installed a new Dtech FSD on an FSD Cooler in May of 2008. I have been through one Optical Sensor and one complete Injection Pump since then, and yet the mighty Dtech soldiered on.... until this evening.

I noticed on the way to work this morning that she was running kind of .... funny. A few blips here and there, but nothing too drastically out of the norm. However, on the way home this evening, I noticed that the throttle was really touchy, and I suddenly had a large power increase! I barely had to touch the accelerator and and I was zooming. Once I got home and put her in park, I tried to rev the engine slightly, and she wouldn't allow me to hold any RPM other than idle or full throttle.

Luckily, I carry a spare FSD for just such an emergency. It's already mounted on another cooler, so I pulled it out and plugged it in, and then everything went back to normal.

I'm quite pleased I got nearly 6 years out of this unit. I installed a brand new Stanadyne FSD in late 2005 when I purchased the Tahoe, and it quit in 2008.

So what's the best FSD to purchase these days? The backup unit currently working is a like-new, low-mileage Stanadyne model that I installed on another truck a couple of years ago that only went a few months before losing compression on one cylinder. I don't want to go for long without another FSD backup.

Casey

[DmaxMaverick]

Are you trying to talk yourself out of the product that worked?

Anyhoo, where did you buy the D-Tech? It may still be under warranty. Many of them were sold with 7, 10 or lifetime warranties.

[arveetek]

Are you trying to talk yourself out of the product that worked?

Anyhoo, where did you buy the D-Tech? It may still be under warranty. Many of them were sold with 7, 10 or lifetime warranties.

For some odd reason, I was thinking that Dtech was no longer in business. I didn't even bother to look! Doh!

http://www.dtechproducts.com/Products/GM-6-2L-6-5L/DT19209057

I'll have to look into the warranty possibility. Thanks!

Casey

[john8662]

This is the Module of choice in my opinion.

The Grey Stanadyne module proved to be worse than the black modules it replaced, and they had to go an screw up the wiring harness plugs too.

I don't like how the Flight Systems PMD's fail, but they do last a lot longer than the Stanadyne modules.

[Artworks]

This is the Module of choice in my opinion.

The Grey Stanadyne module proved to be worse than the black modules it replaced, and they had to go an screw up the wiring harness plugs too.

I don't like how the Flight Systems PMD's fail, but they do last a lot longer than the Stanadyne modules.

Where are you reading / hearing this? I just got one through angelofishes, when I was having trouble with a dtech from Leroydiesel ( 2nd 1 , on warranty) & Kennedy prefers them also.
I think the whole electric pump system sucks, but what gona do, shop for cheapest, & have spare.

[john8662]

First hand experience. Bought 4 in one year new, sold to different customers and got to eat two of them. I won't sell them any more. The key here is that the grey module last longest on the pump. It is not tolerant on a PMD cooler mounted in the engine bay. It may last on a cooler mounted in the bumper, but didn't want to give them another shot when they both were mounted in different spots on different trucks and both failed in 6-8 months time.

J

[More Power]

Stanadyne Corp.
SERVICE LETTER 328R2 dated February 20, 2014


Stanadyne is changing the warranty coverage on DS Pump Mounted Drivers effective with PMD kits sold from March 1, 2014 forward. From that date forward, PMD kits 35976 and 40736 sold over the counter or not installed on the pump per the specification will be covered for a period of 30 days, unlimited miles. In addition, the warranty for PMD’s sold over the counter and/or improperly installed is limited to 1 free replacement PMD during the 30 day warranty period. Suspect PMD’s do not have to be returned to Stanadyne (unless we specifically request them for analysis) but as before, the proof of warranty documents must be emailed to warranty@stanadyne.com

The 2 years, unlimited miles coverage will continue to apply to complete new DS pumps with the PMD installed at the factory (and installed on the engine that way), and to replacement PMD’s that are installed on the pump to specification by the Authorized Dealer (and installed on the engine that way).

[Robyn]

Hmmmmmm, I SMELL RAT HERE.
:eek:

The PMD mounted in the hole did not work the first time through the lunch line.

The new warranty policy seems to follow Stanadynes reputation.

This is a sorry situation.

Back to the DTECH mounted on a remote cooler out of the engine bay, as they should be.

It would be interesting to reverse engineer the Stanadyne PMD'S (BOTH BLACK AND GRAY) and see what the difference is, and then compare them to the DTECH

This really should not be so stinking hard.

Maybe a DB2, DO YA THINK :D

[ginger743]

Hmmmmmm, I SMELL RAT HERE.
:eek:

The PMD mounted in the hole did not work the first time through the lunch line.

The new warranty policy seems to follow Stanadynes reputation.

This is a sorry situation.

Back to the DTECH mounted on a remote cooler out of the engine bay, as they should be.

It would be interesting to reverse engineer the Stanadyne PMD'S (BOTH BLACK AND GRAY) and see what the difference is, and then compare them to the DTECH

This really should not be so stinking hard.

Maybe a DB2, DO YA THINK :D

The reverse engineering wouldn't be so bad if these units weren't , " potted " , that potting makes it really difficult to get into them. I haven't checked what they are , " driving " but I would guess the circuit in the , " black box " is just a switching circuit. Higher power Transistors that could carry more current would be one improvement . When Transistors are overheated they go into what is called , " thermal avalanche " which is with heat the current increases and beyond a certain point it acts like a feedback loop, more heat = more current, more current = more heat until the Transistor junction goes open or shorts .

In the failure mode that we experience with these I would suspect that one of the Transistors is going , " open " since we are not taking out a current limiting device like a fuse or popping a circuit breaker.

Higher power Transistors come in a different , " case style " , which would be no big deal to install them mechanically and to match the electrical characteristics and substitute them into the circuit.

If we could just figure out how to , " unpot " them. I suppose that potting is a type of epoxy .

Jerry

[Dvldog8793]

Howdy
So between myself and a friend we have had three DB4 setups. Over a million miles inclusive. Three failed PMDs and one suspected. 2 black Stanos, one grey stano and the suspected was a brand X....unsure what it was but probably not reputable. Only one of the failed units was mounted on the pump and that one went over 200K miles. One of the grey units had water migration into the case...shouldn't have been an issue but Stano said it was and it turned into my over zealous use of a pressure washer that wrecked it....:rolleyes:. I have tried to "un-pot" one and it really aint gonna happen...I worked for Motorola for a few years and thought I could do it but Stano did do a good job with the potting material!
Also working for Motorola I saw many drivers in worse mounting areas and WAY less heat dissipation go for YEARS without ever failing....????

So I have tried several mounting methods-

Pump mounted....we know the outcome.
Remote mounted with a properly made heatsink on the fender- worked but it did get hot.
Remote mounted with heat sink outside- worked the best.

Here is my idea(not patented:D)- Make a heat sink that uses mass, area and fuel to cool the pmd. In other words an Aluminum fuel block the would also be a mounting point for the filter and contain the PMD with some cooler fins extended to the inner fender well...?

Can anybody tell me a reason this wouldn't work? When I remount my IC this summer this is going to be part of the project.

It also combines the best of all cooling worlds, and gives us a better filter and filter location. We could also increase the diameter of the feed lines and fittings.

I am sure by the time I get this done the bottom will fall out of the engine and then it will time for a 5.9 conversion!:D

[ginger743]

One major problem I see with this design is that the case of the Transistor is almost insulated as far as heat transfer is considered by having it mounted to plastic which doesn't work too well to transfer heat . In our application the body of the Transistor is probably operating at 12 volts and needs to be electrically insulated from ground. When the Transistor is used in other applications it is mounted directly on the heat sink and insulated with a very thin insulator and silicon grease . You've probably seen this on high power audio amplifiers.

It seems what the designers had in mind on this design was that they would rely on the circulating fuel to cool the PMD Transistors .

I have considered taking the , " cover " off of the transistors here and covering them with silicon grease for heat transfer to the heat sink, of course they have to be insulated from the heat sink electrically but I think the spacing would take care of that .

On the other hand we may have adequate heat transfer to the heat sink and just have to concentrate on getting the heat dissipated from the heat sink. We could use any large metal area as a heat sink, even a fender .

When I worked at United Airlines on avionics we would take stuff like this downstairs to the landing gear shop and have them X-Ray it for us to give us a look inside. The Landing Gear shop had some high powered X-Ray equipment :>)

Jerry

[Robyn]

What's odd here is, with the engineering knowledge that Stanadyne posesses, one would think that this little PMD gizmo would be a no brainer to design with a good long service life expectancy. ???????????//

The idea of cooling the PMD with the fuel was not a bad idea, just did not work well in the real world.

The pump sits down in a gawd awefull hell hole that can reach some damned high temps, then they capped the thing with the plastic cover (Turbo power hood)

The poor PMD just cooks in that place.

Interestingly enough, the earlier trucks (92-93) with the DB2 pumps, had zero issues with the covers.
The pump worked fine with the trapped heat, just the electronics does not like it.


The potting material is indeed an epoxy resin of some sort, and for sure, getting it out of there is nearly impossible.

Anything that will dissolve the potting, will take out the other goodies as well.

Be way cool if we could get a hold of an un-potted PMD to peek at.

Anyone know a mole ??? :D

Missy

[ginger743]

What's odd here is, with the engineering knowledge that Stanadyne posesses, one would think that this little PMD gizmo would be a no brainer to design with a good long service life expectancy. ???????????//

The idea of cooling the PMD with the fuel was not a bad idea, just did not work well in the real world.

The pump sits down in a gawd awefull hell hole that can reach some damned high temps, then they capped the thing with the plastic cover (Turbo power hood)

The poor PMD just cooks in that place.

Interestingly enough, the earlier trucks (92-93) with the DB2 pumps, had zero issues with the covers.
The pump worked fine with the trapped heat, just the electronics does not like it.


The potting material is indeed an epoxy resin of some sort, and for sure, getting it out of there is nearly impossible.

Anything that will dissolve the potting, will take out the other goodies as well.

Be way cool if we could get a hold of an un-potted PMD to peek at.

Anyone know a mole ??? :D

Missy

Yes !!

And that 30 day warranty doesn't instill confidence in their product either, on their part !! It guarantees the product to work but says nothing about it's design / durability longer term.

Jerry

[Robyn]

With today's technology, the damned thing should work even if you bolted it to the exhaust manifold :eek:

Yeah, that 30 day thing runs my BS flag clean to full staff, and quick

Tells me 100% that they are peddling a POS

GM had a hand in the design criteria too me thinks, and therein lies the problem.

GM could have made these engines a common rail, and there were experiments along such lines.

Even an external system would have been workable
They could have mounted the High Pressure pump in the same location as the DS system is located and run an electronic injector.

Sadly, they chose to try an easy route and , well the rest is a pathway littered with the corpses of the fallen and broken parts.


And as they say, "That's how the cookie crumbles"

Missy

[ginger743]

With today's technology, the damned thing should work even if you bolted it to the exhaust manifold :eek:

Yeah, that 30 day thing runs my BS flag clean to full staff, and quick

Tells me 100% that they are peddling a POS

GM had a hand in the design criteria too me thinks, and therein lies the problem.

GM could have made these engines a common rail, and there were experiments along such lines.

Even an external system would have been workable
They could have mounted the High Pressure pump in the same location as the DS system is located and run an electronic injector.

Sadly, they chose to try an easy route and , well the rest is a pathway littered with the corpses of the fallen and broken parts.


And as they say, "That's how the cookie crumbles"

Missy

Yup,

In one of my posts I said this ,

" It guarantees the product to work but says nothing about it's design / durability longer term. "

actually it does say something about long term, it ain't gonna work beyond 30 days . LOL Or " we're not betting it'll work beyond 30 days " LOL

" We're not putin' our money on it " LOL


GM should have recalled this and redesigned it the first few times it went into non-commanded full throttle !
Jerry

[More Power]

Potting is used for a variety of reasons.

1- Vibration resistance.
2- Environmental resistance.
3- Proprietary control.

An argument could be made that being potted is a cause of many PMD failures.

Thermal expansion/contraction works on the module every thermal cycle of the engine. Being potted with a hard plastic compound, the components and circuit board are held rigidly in position regardless of the expansion/contraction and differing thermal expansion rates for plastic, fiberglass, copper, lead and steel. This may cause a solder joint or component to eventually fatigue or lose contact. I feel Stanadyne used the hard plastic potting to discourage the curious.

Some of the electronics used in the aircraft radar systems I worked on in the Navy were potted using a dense silicone compound - not a rigid hard plastic. This allowed for thermal expansion to occur without stressing the components, and in an emergency, we could repair the circuits (I was a bench level tech) by removing a portion of the compound.

Some erratic PMD behavior can be solved by simply re-tightening the screws holding the power transistors. The screws worked loose over time. The metal case of a power transistor is part of the circuit.

[arveetek]

On the other hand we may have adequate heat transfer to the heat sink and just have to concentrate on getting the heat dissipated from the heat sink.

Jerry

I'll tell you this: the FSD cooler that my FSD is mounted to will get severely hot when worked hard. It will burn your hand. That tells me the heat is being transferred to the fins just fine from the FSD. Getting the heat dissipated from the heat sink is the key, I believe. Well, only since our options are so limited anyway! ;)

Casey

[ginger743]

I'll tell you this: the FSD cooler that my FSD is mounted to will get severely hot when worked hard. It will burn your hand. That tells me the heat is being transferred to the fins just fine from the FSD. Getting the heat dissipated from the heat sink is the key, I believe. Well, only since our options are so limited anyway! ;)

Casey

I think your right Casey !!

Your , " touch test " bears this out :)

Jerry

[phantom309]

Mounted in the front bumper hole seems best,. stays pretty cool here in -25f weather,..:D

[Robyn]

Has anyone tried fabricating a "liquid cooled" heat sink that would place the PMD in close proximity to the liquid medium. By this I mean withing 3/16' or so and circulating the coolant through the heat sink and a little radiator.

With all the high tech water coolers for computers now available for the go fast GEEKS, it seems to me that adapting one of these little systems would be very easy.

The pumps for these units run on 12 volts, hmmmm, seems we have that right handy.

Some creative adaptation and fill the system with some of that super coolant that's used.

The system could be wired in to start with the engine.


It would be very easy to create a custom heat sink that would accommodate mounting the PMD.

An aluminum block with coolant passages and a nice smooth flat mounting surface would be easy to create.

Here is a link to an outfit that sells the cooler kits for computer coolers
www.frozencpu.com/cat/l1/g30/Liquid_Cooling.html‎

These parts could easily be tweeked to become a PMD cooler

The super go fast CPU'S in today's computers will fry and egg in seconds without a good cooler.

I had thought about adding a water pumper to my latest computer, buttttttttttttttttttt.

Just a thought.

Missy

[ginger743]

Has anyone tried fabricating a "liquid cooled" heat sink that would place the PMD in close proximity to the liquid medium. By this I mean withing 3/16' or so and circulating the coolant through the heat sink and a little radiator.

With all the high tech water coolers for computers now available for the go fast GEEKS, it seems to me that adapting one of these little systems would be very easy.

The pumps for these units run on 12 volts, hmmmm, seems we have that right handy.

Some creative adaptation and fill the system with some of that super coolant that's used.

The system could be wired in to start with the engine.


It would be very easy to create a custom heat sink that would accommodate mounting the PMD.

An aluminum block with coolant passages and a nice smooth flat mounting surface would be easy to create.

Here is a link to an outfit that sells the cooler kits for computer coolers
www.frozencpu.com/cat/l1/g30/Liquid_Cooling.html‎ (http://www.frozencpu.com/cat/l1/g30/Liquid_Cooling.html‎)

These parts could easily be tweeked to become a PMD cooler

The super go fast CPU'S in today's computers will fry and egg in seconds without a good cooler.

I had thought about adding a water pumper to my latest computer, buttttttttttttttttttt.

Just a thought.

Missy

Maybe folks that have relocated the unit behind the bumper can give us some feedback on their failure rate after this relocation .

I question this choice of location, here in the desert when it's 115 degrees and no one knows what the air temp is off of the road . Now when were stopped in traffic or at stop lights we have little to no air flow over the unit, it just sits there and bakes.

One person awhile back suggested mounting the unit in the passenger compartment with a small PC type of fan blowing over the heat sink. I would prefer this over the behind the bumper mount .

Jerry

[Dvldog8793]

I posted earlier in this thread that I have been thinking of making a different type of fuel filter block/PMD mount that would use fuel to cool the PMD. This would be using the same logic as the pump mounted idea but also incorporating the cooling fins and remote mount. It will also have a better fuel filter in a more accessible place.

Opinions?

Thoughts on why it wouldn't work?

Does anyone know if a longer feed line to the pump will create problems?

[Robyn]

The fuel idea seems to me to have great merrit.

This too would be easy to build and would certainly allow the heat to be carried away.

My only question is where to mount this type of cooler ???

Getting the PMD out of the engine bay is certainly a worthwhile plan.

I have seen the PMD mounted under the lower edge of the dash on a cooler that had a little fan on it, plus had the advantage of the AC keeping the interior cool as well.

In hot weather, I don't think anyplace outside is really the total answer.

As mentioned, the outside temps can get extremely hot.

The cooler the better for sure.

I know, pack the sucker in Dry ice in a little box :D

Using ambient air is only as good as the outside temp, and using a cooler inside the cabin would certainly allow for a cooler air flow.

The diesel fuel is going to be "relatively cool" as compared to the engine bay temps or the air temps, but still does not offer an extreme amount of heat dissipation.

[ginger743]

I posted earlier in this thread that I have been thinking of making a different type of fuel filter block/PMD mount that would use fuel to cool the PMD. This would be using the same logic as the pump mounted idea but also incorporating the cooling fins and remote mount. It will also have a better fuel filter in a more accessible place.

Opinions?

Thoughts on why it wouldn't work?

Does anyone know if a longer feed line to the pump will create problems?

Sounds great, only problem is finding room to locate it. Have the Filter and heat sink mounted on an aluminum block / plate that has fuel running thru it, of course the more pathways for the fuel to flow thru the aluminum block / plate the more heat transfer.

I think in previous discussions on this subject someone actually took temperature measurements of the various components, like the injector pump , fuel from the tank etc.

I have a real mickey Mouse setup, I mounted the Heat Sink on one of the AC compressor mounting bolts with air from the engine fan blowing across it, a really bad idea with 200 degree air from the radiator blowing on it, it's been good so far for 2 years. I don't drive the truck much and it's only been approx. 12,000 miles , not much time. However it's been thru 2 summers here in the desert heat. I did this in a hurry to eliminate the need to remove the failed unit from the pump and mount the new one in the original location. Since this has lasted 2 years certainly doesn't tell me this was a good idea, actually it's not .

[Robyn]

We bought a 95 Burb Diesel new in 95.
Ordered it new with all the options available.

First PMD FAILURE was at 24k miles (one afternoon, would not start after hot shut down)

Dealer replaced the IP (NORMAL MO back then)

Second PMD failed 6 months later at about 30k miles.

Same same at the dealer.

The 3rd PMD FAILED at 60k miles in 1997
Dealer replaced IP

We offed the truck within aa week and traded it for one that was identical with the 454 engine that had 65k miles

That rig had 320k on it when we sold it.

The original PMD" failed regularly on some rigs.

[arveetek]

I don't think I'd want my FSD in the bumper; I've done too many creek and river crossings on some of my expedition trips where the water was up that high! (I've extended the breathers on the diffs and transmission to prevent water intrusion on those items). I'm not keen on the idea of taking a rather fragile unit and then dunking it in water.

My backup FSD is currently mounted on a spare cooler and zip tied close to my brake booster. Just temporary mounting until I get another FSD on the FSD Cooler. This one is a fairly late model, low-mileage Stanadyne unit (black, just before the gray units came out).

I don't want to mount my FSD inside the passenger compartment, since on hot summer days my A/C has a hard time keeping me cool already! I don't want to add another heat source inside.

Casey

[Yukon6.2]

Hi ginger743
I imagine your AC is working fine in that heat?
I remember reading someone had relocated theirs so the AC would always blow cold air over the heat sink.If you live somewhere that you would have your AC on most the time that should be a better alternative to 18" up from some hot as hell blacktop.
Thomas

[ginger743]

Hi ginger743
I imagine your AC is working fine in that heat?
I remember reading someone had relocated theirs so the AC would always blow cold air over the heat sink.If you live somewhere that you would have your AC on most the time that should be a better alternative to 18" up from some hot as hell blacktop.
Thomas

Hi Yukon,
Yup, my AC is working great, I took the compressor apart and replaced all of the seals and "O" rings , it hadn't disintegrated , it was just leaking around the body and wouldn't hold a charge.

I did consider that a lot of heat would be brought into the Pass compartment if I relocated there.

What if we double the Heat Sink area by " sandwiching " the PMD between 2 Heat Sinks ? I wonder how hot the side of the PMD gets that doesn't have the Transistors mounted on it , if that side gets really hot a second Heat Sink would help I would think.

I don't run the AC here all the time, it gets cold here at times, down to 17 degrees a few times last year, not that cold this year.

Yup , that behind the bumper idea just doesn't sit well with me but neither does the set up I'm using now :confused: A person could calculate how many watts is being generated in heat on the Heat Sink but it would take a lot of work measuring voltage drop across the circuit etc. I still like the under dash fan idea. I would put a label under the hood near the radiator to inform the next person that ends up with the truck where the PMD is located if I moved it into the pass compartment. That black top has to be putting off some serious heat. With the truck sitting in the sun here in the summer time the inside temp reaches 140 degrees.

I was just looking at HF and they have an infrared , " thermometer ' for $19.99 . I think I'll drop by there and get one of those. They have great reviews on the site. Then I can check the temp differential between the air that comes out of the radiator and the Heat Sink to see how well that engine air is cooling the heat Sink. Just something to play around with. I'll check the radiator or block Temp and compare that with the Heat Sink.

Jerry

[DmaxMaverick]

Underhood air is nothing to "play around" with. Consider this.... Thermostats are 180-195°. Fan clutch engagement temp is around 160°. If your ECT is "normal" and your fan is near the temp of engagement (it should be any time, at operating temp), it's at least that hot. All this before the engine block/heads and exhaust manifolds, turbine plumbing (900°+, under load), etc. Anywhere under the hood is not a good place for the PMD on an air/air heat sink. In the HVAC duct, AHEAD of the core stack would be a "good" place. After the core stack would be very bad (remember the coolant temp, sans-stat control). Behind the bumper on a good heat sink is good (despite the reservations). There are other good places, as well. Kennedy likes it in front of the battery (up and away from the ground, in good fresh airflow). Do whatever you have to do, but do yourself a favor and get it out of the engine compartment, or just leave it on the pump.

Liquid cooled electronics is nothing new, and is still used for many applications. The early Duramax has the injector driver plumbed between the filter and pump (it also has a cooling core in the return to the tank), and it's been used on aircraft, for decades. The PC cooling stuff (pump, exchangers, sink, etc.) would probably do very well. The parts are relatively inexpensive.

[ginger743]

Underhood air is nothing to "play around" with. Consider this.... Thermostats are 180-195°. Fan clutch engagement temp is around 160°. If your ECT is "normal" and your fan is near the temp of engagement (it should be any time, at operating temp), it's at least that hot. All this before the engine block/heads and exhaust manifolds, turbine plumbing (900°+, under load), etc. Anywhere under the hood is not a good place for the PMD on an air/air heat sink. In the HVAC duct, AHEAD of the core stack would be a "good" place. After the core stack would be very bad (remember the coolant temp, sans-stat control). Behind the bumper on a good heat sink is good (despite the reservations). There are other good places, as well. Kennedy likes it in front of the battery (up and away from the ground, in good fresh airflow). Do whatever you have to do, but do yourself a favor and get it out of the engine compartment, or just leave it on the pump.

Liquid cooled electronics is nothing new, and is still used for many applications. The early Duramax has the injector driver plumbed between the filter and pump (it also has a cooling core in the return to the tank), and it's been used on aircraft, for decades. The PC cooling stuff (pump, exchangers, sink, etc.) would probably do very well. The parts are relatively inexpensive.

How about this;

Mounted in front of the Radiator, this would take care of the , " no air problem " when stopped at a stop light or in traffic ? At idle there may not be much air being pulled thru the radiator but some is better than none.

Jerry

[ToddMeister]

As John Kennedy suggests, my PMD/Heatsink is mounted in front of the LH battery, it has been there for the past 8 years with no troubles.

[arveetek]

As John Kennedy suggests, my PMD/Heatsink is mounted in front of the LH battery

Mine too. (Except for my temporary backup unit at the moment.)

Casey

[ginger743]

As John Kennedy suggests, my PMD/Heatsink is mounted in front of the LH battery, it has been there for the past 8 years with no troubles.

That's where mine is going also !! Hard to beat 8 years of no failure !!

Jerry

[DmaxMaverick]

Most (if not all) of the success and failure stories are anecdotal. Truth be told, I've had/seen fewer issues with the PMD mounted on the pump. I remote mount them, more as a convenience of location, while reliability variations are only slight. The design is unreliable, as a whole. I think overall reliability depends on the individual quality of the components, and not so much what we do with them once in-hand. The design can be improved, of course, but I don't think we'll end up with a complete fix. Not yet, anyway. Sol-D, for example seemed, at first, to be the "fix" (in the sense it was better, at the time, than previous solutions). I've not heard of one actually failing, but they have issues with temperatures and system voltage sensitivity during cold starts. A perceived failure is a failure, nonetheless.

[Robyn]

We had a Sol D on the 94 Burb, and it suffered in cold weather.

At temps below 30F the thing was useless.

During cold weather I would take it in the house at night, then plug it in in the morning, and good to go.

If we were going to be out somewhere for long periods, I had the thing rigged with wing nuts on stud topped bolts on the air hat, so I could simply take the thing with me in my coat pocket and keep it warm.

Real PITA WHEN COLD.

When cold, if I jumped the big rig (idling at 14.5 volts) to the Burb, which raised the line voltage, then the SOL D would fire.
Checking the voltage to the Sol D with the jump in place revealed a good 12v and without the jump, it was at 10v
This 2 volt difference was just enough to keep the mosfet from working. At cold temps they need a tad more ooooomph to reach the threshold.
At warm temps, not so much.

It finally started popping codes and died one day.

Went to the DTECH on a bumper mount and never had any more issues.

The Sol D was a mosfet setup, and at low temps would not work.

This was due to more voltage requirements than the system could deliver.

The wires are very tiny that feed the PMD and considering the long drawn out circuit distance, there was significant voltage drop.

Some rigs seemed to eat PMD'S and others did not.

I am very suspect that the wiring in some trucks may have had issues that caused the PMD failures.

Poor grounds, back feeding, low voltage ???????????

One could consider rewiring the harness that feeds the PMD 12v and use the 12v feed to power a little relay that then supply battery voltage directly to the PMD from the relay.

Poor voltage to the PMD can and will result in high amperage draw, which is very basic. As the volts drop, the amps go UP :eek:

Make sure that the PMD IS GROUNDED TO THE IP

You might even extend the IP ground to the battery ground terminal just to rule out back feeding.

One issue with poor grounds is that no matter where it is, a device with a poor ground can impact the entire system, and the sensitive electronics will suffer from it.

A poor ground in the transmission can cause troubles elsewhere, and be a bitch to find.

I had a broken ground once in an HEI distributor on an 86 GMC 4X4.

The truck ran fine, but when you stepped on the throttle hard the wipers would cycle :eek:

Had I not just been in the Distributor doing a tuneup, it would have been tough to locate.

Removing the top cover revealed a broken ground wire at the point it crimped into the terminal that connected to the harness.

With the increased use of fairly sensitive electronics, there exists far more chances for issues in the system.

Missy

[Artworks]

Robyn, do you run an extra wire from the pump to the remote PMD / FSD heat sink for ground? I got Dtech mounted front of the LH battery and now a Grey standyne in bumper behind lic. plate.

[Robyn]

Leave the wiring harness that is on the IP connected as it was at the factory, then plug in the extension harness, one end to the PMD and the other end to to the original harness.

Good to go.

Now if you wanted to secure a separate ground under the screw on the IP that is the harness ground, and connecting it to the battery NEG, it will not hurt anything.

Also a ground connected to the remote PMD heat sink and back to the battery ground will also hurt nothing.

Extra grounds will not hurt anything.

Ground the chassis to the frame, ground the engine to entire system, as this is done indirectly anyway by the factory battery ground cables, which get replaced by aftermarket stuff that lacks the connection to the inner fender.

All the chassis, engine, frame and components must be securely grounded and the entire she bang must be included in a secure and complete ground.

Most class 8 trucks do not use the frame/chassis as the ground plane, but instead run a ground wire to each component.

This helps eliminate the back feeding and poor operation of electronic components, lights and other equipment.

Rigs that run in salt country are subject to premature ground failure due to corrosion.

One ground failure anywhere can set the stage for weird stuff to start happening, no matter if its a light circuit, or something far more critical.

Once there is electrical current "Roaming around" trying to find a ground, there is no telling what anomalies will occur.

Lights such as trailer lights that are not properly grounded do all manner of weird crap, but seldom hurt anything, not true with sophisticated electronics.

Missy

[Artworks]

I am well aware of grounds giving problems.
Last I swapped my S intake for F type, & fixed a leak at the fuel manager, changed couple hoses, replaced o"rings. Bled fuel filter & lines, hooked up batteries & tryed to fire up. No WTS light or engine light, [I]figured it was relearning & cycle glows a few starts (OBOI). Didn't want to start ,soI pluged block heater in and had bite to eat. Came back, still no start? Checked at couple injectors, NO FUEL !I went & checked all wiring hook ups & at back block by glow relay & ops, I missed couple wires ( black 16ga.) that should have been under a nut on the stud. It fired right up. I probably run couple extra grounds to my remote FSD'S. I run half doz. extra's from batteries to engine & chassis already.
Friday morning after a short trip, I am checking things under the hood w/ engine running & notice coolant pouring out WT_ ? Shut down & check, my rh block heater leaking like Niagra falls ! Got appointment Mon. morning to get up hoist & get changed.
IF NOT ONE THING IT'S NOTHER !