Good place to relocate PMD to

[xtrempickup]

I have a 6 ft cable i bought to relocate my brand new PMD that I also purchased. I see in advertisements to mount it near the hole in the front bumper, i think that might be a little too close to the elements and danger. I see some in the cab on the floor. any other places that are good? i was thinking in the center console or the glove box or just on the fender near the air box intake. anybody ?

[Jochen Woern]

I got mine on the inside of the fender well, drivers side.
Check out www.kennedydiesel.com and look at the 6.5 diesel upgrades, FSD Cooler package. You will see some pics there, the second one shows exactly where mine is located.

Any further questions, just let me know.

[Robyn]

You can put it on the aluminum skid pan that folds down under the radiator area.

The Idea is to keep it in an area that has lots of the coolest air flowing possible. The Nostril in the pumper is not a bad spot. If the sucker gets mashed the PMD will be the least expensive of the damage.

If the PMD is on the inside of the Nostril the weather pack connector will be fine to keep things sealed up.

The main issue is keep it as cool as possible.

I have mine on the 94 Burb on the inside of the front skid pan under the radiator.


Anything is better than that hell hole down under the manifold.
The top of the engine is poor too as the heat collects there.

Cool wind swept spot is the best.

Robyn

[xtrempickup]

sounds good

[Robyn]

Just rereading these posts.

Put the PMD on the inside of the skid pan. I was not specific in this. :eek:

The PMD is totally sealed and the only place anything can cause issue is the connector. The connector should be very fine as long as it is not submerged in water.
If you are going to go on a fording operation I would place the PMD in a spot thats above the high water mark for sure.

Anyplace out in the area behind the grill is good too.

The issue with the PMD is that high residual heat will shorten the life of the two power transistors in the PMD and possibly other components in there too.
I have not cut one of these little guys apart so I dont know exactly whats in there but they dont like heat, this I do know.

I have seen a couple of the PMD's placed on a custom cooler that was clamped to the AC accumulator over on the RH side of the rig.

The accumulator is very cold when the ac is running and during the summer that should be most of the time.

However the plan to get the little critter out of the engine bay seems to work the best.


Robyn

[xtrempickup]

but is the summer heat considered that big a deal considering its not nearly as hot as i'm guessing it would be on the IP. i still have yet to locate this thing. i havent looked either. where is the IP on the motor?

[Robyn]

The IP is down in the valley between the heads under the front of the manifold.

The PMD needs to be out of the engine bay, Nuff said :D

Robyn

[Jochen Woern]

As mentioned below, go to www.kennedydiesel.com and see for yourself: There are pics as to where the PMD could be located at. Not sure WHY Robyn is so particular about it having to be located outside of the engine bay. (Because this is what you did Robyn???) :rolleyes:

Why would a company like Kennedy show where this thing could be located at if it is no good? There are also many companies suggesting to locate it above the intake, still within the engine bay.

I would say that ANYTHING is better than down in the valley between the heads, right? My Burb had its first failure of the original PMD at close to 168K miles. The Burb is an original CA truck and therefore spent all its years in the CA heat. Nuff said. :)

[sturgeon-phish]

I have a 2 wheel drive and as such no skid plate. Mine is mounted on a heavy aluminum plate mounted under the bumper, FSD on the backside. I've laid my hand on the FSD after a long hard pull in summer and was only warm to touch. Big difference. Get the FSD in the air flow, lots of places. Some mount on the intake to avoid an extension harness. Like Roybn said, out of the engine bay is best.
Jim

[arveetek]

Mine is in Kennedy's suggested location, in front of the driver's side battery on PMD cooler.

Did you get a cooler as well, xtreme?

Casey

[DA BIG ONE]

I've had my IP drivers located in many areas outside of engine bay and now have them in airflow to radiator to better cool them when stuck in traffic or at idle. When parked w/ac on I switch to hi-idle via switch no issues just cold ac and cool running 6.5td.

I do have a WARN Classic winch bumper and IP drivers are mounted to it. Thinking factory bumper offers less area to mount units in air path to radiator.

As for getting units wet I've found no issues with either unit (1) which I sealed all the edges and at plug thinking it was needed, (2) unsealed when submerged in deep water on many occasions. Dielectric gel at plug to lube and seal plug seal is always a good idea.

[Robyn]

Does not matter a tinkers whizzzzz what I did. The issue is get the PMD away from as much heat as possible and still keep it safe.

I have seen them inside the cabin mounted on a cooler with a computer fan on them.
In the engine bay by the battery where JK mounts them.
Down in the bumper nostril
On the skid pan under the radiator
On the AC accumulator.
On the inner fender
On the manifold air hat (Bad choice)

It makes little difference where it is mounted as long as there is plenty of cool outside air getting to it.
The only limiting factor will be the creativity of the person who mounts it and the length of the extension cable that is available.


I respect John Kennedy and have no particular issue with the behind the battery location but I still feel that outside the engine bay is better because its cooler.

The outifts that are still calling for mounting on the intake air hat location are selling a product and in my opinion have not done any research to see that the location and the resultant temp of the PMD is actually no better up top than on the IP and possibly hotter.

My prefered location is anywhere its cool with lots of air circulation and one that is easy to get to in case you need to change the little critter along side the road.

Even a remote mount in a good location is not a 100% guarantee that the PMD will not fail.

The PMD is still a fragile piece of electronics and is very susceptible to heat failure.

The jury is still out on the new DTECH units. I am running one on DaHooooley and we shall see.

This thread basically started with a question as to where to mount the PMD.
So we have a variety of input here as to where to put it.

Bottom line, keep it as cool as you can and in a place that it wont get damaged during off road operations.

I have no issue with a lot of different locations.

What I have stated in my replies is my choice and thats about the long and the short of it.

KEEP IT COOL AND you will have one of these. :D

Best

Robyn

[xtrempickup]

New PMD arrived today. I have the new 6 ft cable also. One question more since i have not taken the old one off yet or anything. I see the cable that came with the PMD is short with a ground wire and a rubber cover on another portion that sorta resembles an A/C eletric plug, not exactly but i think you might understand what i mean. Do i remove the old unit and still use this cable with the ground and only plug the 6 ft one into it and move the PMD where i want it? I notice i get a thin piece that sorta looks like a gasket with it. Do i need anything underneath the PMD when i mount it with thin gasket type square. I see all those cooler type things and didnt buy one figuring a lot looked like gimics These things are more just prone to heat for failure, so i take it that if i dropped it it wouldnt affect it tooo much but i shouldnt play hockey with it

[JohnC]

Did I miss something? We've discussed where to mount it, but I don't think we've discussed what you are going to mount it on. If you move it fromthe pump you need a big heat sink to dissipate the heat.

Time has shown that many PMD failures are actually failures of the cable connecting it to the rest of the electrical system, hence the new cable included with the PMD. I'd use it.

The gasket is a thermal transfer gasket. Use it as well, once you've figured what you are mounting it to.

Don't drop it, either. I'm convinced the problem is more due to mechanical stresses generated by thermal cycling than due to the heat itself.

[xtrempickup]

any particular way to make a heat sink or something i can use without purchasing and waiting another week to do anything to this truck. cant i just mount the PMD to bumper by the nostril or the radiator support behind the grill and be done with? i figured the air flow would be enough to dissipate heat unless i'm missing the whole reason to locate it to a place with there is cold air flow. does the IP have a heat sink or is the PMD just screwed to it? i'm trying to figure out what the heat sink is for if the PMD is always in the line of moving air or at least not near any source of heat?

[JohnC]

The IP is designed to remove the heat by circuating fuel through the part of the housing where the PMD mounts. Lift pump failure is, IMHO, one of the chief causes of failure, sort of like having the water pump fail and the engine overheat...

[xtrempickup]

That isnt answering my question completely. I dont have a heat sink. Do i need a heat sink? If i don't have one, what can i use for one or do i necessarily need to buy something else or can I just mount it and done with. I know my lift pump wasnt working for a while, might not be working now, but thats a separate issue, one thing at a time as the truck still runs but i would like to stop the stalling

[JohnC]

Yes, you need a heat sink.

I cannot recommend making one, but if you do, bigger is better and be sure you get a good thermal bond between the base of the PMD and the body of the heat sink. Whatever you mount it to has to be able to dissipate the heat generated by the 2 switching transistors in the PMD. Mounting it without one is worse than leaving it where it was.

The failed lift pump may well be the cause of the failed PMD.

[xtrempickup]

This lift pump and oil pressure switch i replaced about a year ago so for it not to work it may only not be working a short time. I guess i need to look for a heat sink now.

[More Power]

The outifts that are still calling for mounting on the intake air hat location are selling a product and in my opinion have not done any research to see that the location and the resultant temp of the PMD is actually no better up top than on the IP and possibly hotter.

Actually..... The company who developed the very first commercial FSD cooler is owned by an engineer (Christer Lindstrom), and he did the research. You can read more about his research data in the following two articles, which have been available to the public here in The Diesel Page since 2000...

http://www.thedieselpage.com/reviews/FSDCooler.htm

http://www.thedieselpage.com/reviews/beta.htm

Having said that, my opinion has evolved somewhat through the years, and I suggest placing the cooler in a location where it gets plenty of outside ambient airflow. I believe thermal cycles have an effect on FSD reliability, and even if the intake mounted FSD does, according to Christer's careful test data, show it to be a perfectly suitable location, the heat soaking that the module endures when shutting off a hot engine could produce a cumulative negative effect on the module.

We've learned that there is no cure-all location when using the Stanadyne FSD module. Even Heath's PMD Isolator has failed in at least two instances that I know of, and his is mounted in the coolest location possible. While I have heard of original pump-mounted modules lasting for as much as 450,000 miles, most don't run a fraction of that. The root problem remains the imperfect design of the Stanadyne module.

When people call or email me about this subject, I suggest they install a remote cooler (I suggest several, and let them choose which one) in a cool location for one primary reason - to allow changing the module on the side of the road and in the middle of the night with a flashlight. You can't do that while it's mounted to the injection pump. I also suggest they carry a spare module with them if they travel away from home with this vehicle. :)

Jim

[DA BIG ONE]

My 3 units could be considered overkill but any FSD issues are short lived by simply unplugging the dummy plug from spare, and active plug from failed unit then switching them. Had to do this once when my IP was failing the unit I switched to had a #9 resistor that kept my truck running until I had replaced IP (mechanical cam ring failure).

My first thought was the FSD w/#5 resistor was bad "it wasn't". Bill Heath pointed out that the #9 had enough extra fuel to run motor and the IP would have to be replaced soon "he was right".

[Robyn]

Let me add this.
All the advice here is great stuff.
Just be sure that whatever cooler you buy is beefy and that the mounting surface is FLAT. dont pull the FSD/PMD down onto a surface thats not nice and flat.
The gasket/heat transfer pad that comes with the new FSD is good but you can also use the heat tranfer paste (White goop) that is used in computers to mount the cooler to the processor.

Coolers are what coolers are. They should be rugged with plenty of stiffness in them and have a nice compliment of fins to expose as much surface to radiate heat as possible.

All the vendors here offer good stuff
Ebay is full of heat sink stuff and cables too.

I have made them from heat sink stock that I bought at the aluminum dealer in town. The stuff is a simple extrusion.
The last one I set up for a fellow I made here and machined the back surface nice and flat on the mill.

Just take your pick of the sellers as most are very good. Just be sure the unit is flat.

The options for a PMD are limited to the Stanadyne unit and now the DTECH unit.

I dont believe there are any others but there may be as new stuff is coming on the market all the time.

Good luck and happy hollidays
Robyn

[xtrempickup]

Ordered my heat sink, now just have to wait for that to come also and pick the mouting spot where it will get the most breeze and is easiest to do with zip ties or something. thanks everyone for your input

[More Power]

replaced IP (mechanical cam ring failure).

Did you see the cam ring in the failed pump, or was this confirmed by the pump shop? Did you try the pump using a replacement FSD with a #5 or 7 resistor?

I have most of the internal parts from a failed DS4 in the shop. The rollers are badly worn, but the cam ring looks virtually untouched. See below. The new roller is there to show what they're supposed to look like. The "ceramic roller" is actually just ceramic coated.

http://www.thedieselpageforums.com/photopost/data/500/camring_rollers.jpg

[DA BIG ONE]

Did you see the cam ring in the failed pump, or was this confirmed by the pump shop? Did you try the pump using a replacement FSD with a #5 or 7 resistor?

I have most of the internal parts from a failed DS4 in the shop. The rollers are badly worn, but the cam ring looks virtually untouched. See below. The new roller is there to show what they're supposed to look like. The "ceramic roller" is actually just ceramic coated.

http://www.thedieselpageforums.com/photopost/data/500/camring_rollers.jpg

The truck would start, run awhile, stall again and generally run like cr_p, I switched to the FSD that had a #9 resistor truck ran but was using lots of fuel. I sent back to Heath the FSD w/5 resistor and he reported back to me that the parts checked out fine, and that I would more likely than not need an IP soon.

The code for mechanical cam ring failure p0251, or? was ever present, and no I did not see the damaged cam ring and have the pump sitting on a bench here. There are not a lot of miles on this unit.

[More Power]

DTC P0251 "Injection Pump Cam System" does not address and is not about the cam ring and rollers illustrated above. It's about the Optical Encoder Sensor and its ability to read an encoded disc.

http://www.thedieselpageforums.com/photopost/data/500/OES.JPG

The optical encoder sensor provides a "pump cam signal" to the PCM by reading through a perforated disc, allowing it to count the pulses of light that shine through. I suppose the term "pump cam signal" was carried over from other applications, but was repurposed here in the DS4 and PCM.

So, you had an optical encoder sensor problem, which is not a wear issue - more likely an opto/electronic one. This was a big problem in the 1994-95 model DS4's, which Stanadyne designed around with a new style OES (Optical Encoder Sensor) assembly. The early versions failed because of a solid potting compound, which didn't allow for adequate thermal expansion. The newer style OES was "unpotted".

I'm not sure how an OES problem could be related to or affected by the FSD or resistor value.

Incidentally, P0251 (and a few others) can be caused by air in the fuel system. Some have theorized that dyed fuel can cause this as well.

Jim

[DA BIG ONE]

DTC P0251 "Injection Pump Cam System" does not address and is not about the cam ring and rollers illustrated above. It's about the Optical Encoder Sensor and its ability to read an encoded disc.

http://www.thedieselpageforums.com/photopost/data/500/OES.JPG

The optical encoder sensor provides a "pump cam signal" to the PCM by reading through a perforated disc, allowing it to count the pulses of light that shine through. I suppose the term "pump cam signal" was carried over from other applications, but was repurposed here in the DS4 and PCM.

So, you had an optical encoder sensor problem, which is not a wear issue - more likely an opto/electronic one. This was a big problem in the 1994-95 model DS4's, which Stanadyne designed around with a new style OES (Optical Encoder Sensor) assembly. The early versions failed because of a solid potting compound, which didn't allow for adequate thermal expansion. The newer style OES was "unpotted".

I'm not sure how an OES problem could be related to or affected by the FSD or resistor value.

Incidentally, P0251 (and a few others) can be caused by air in the fuel system. Some have theorized that dyed fuel can cause this as well.

Jim

I'm trying to remember just who swore to me it was a mechanical failure to the cam ring? Drawing a blank, but I have asked in past postings what neg effect if any would hi-pops have on the life of the cam ring because I read somewhere that the excessive pressure required to pop the the injectors could damage the cam ring, thinking I fell for some BS along the line.

Anyway, I use a blue tinted 2 cycle oil added to my fuel and have been for awhile considering this might have been the issue then but what about now? Could this be my missed counts detected by scanner? Mechanical pump seems to be in the near future for me.

[More Power]

I'm trying to remember just who swore to me it was a mechanical failure to the cam ring? Drawing a blank, but I have asked in past postings what neg effect if any would hi-pops have on the life of the cam ring because I read somewhere that the excessive pressure required to pop the the injectors could damage the cam ring, thinking I fell for some BS along the line.

Anyway, I use a blue tinted 2 cycle oil added to my fuel and have been for awhile considering this might have been the issue then but what about now? Could this be my missed counts detected by scanner? Mechanical pump seems to be in the near future for me.

Page 6-2273 of the 1998 GM service manual discusses P0251 in more detail.

The DS4 fuel injection pump's main shaft turns at the same speed as the engine's camshaft (1/2 engine speed). So, a signal generated by the OES could be used to indicate camshaft position. The Duramax also uses a cam position sensor as part of its EFI system, but it reads a notched wheel mounted onto the face of the camshaft.

The distance is so small between the OES emitter and sensor that the fuel would have to be nearly opaque to prevent light from shining through the coded disc. So, I wouldn't necessarily agree that dyed fuel or fuel treatments could affect a typical and normally operating DS4. I wouldn't worry about dye used in the 2-cycle oil. Air in the fuel system is mentioned in the manual as a potential cause for a P0251 because a bubble could optically interfere with the light.

Also, the GM manual suggests that for a P0251, the fuel injection pump would need to be replaced once eliminating a possible wiring problem. If the problem persists, they then suggest replacing the PCM.

Some here have replaced a defective OES without removing the DS4 from the engine. There is a calibration procedure that needs to be performed at a pump reman facility when installing a replacement OES, so it would take luck, trial & error, patience, as well as a good understanding of how the OES contributes to EFI to be successful when doing it in the truck. :)

Jim

[More Power]

I'm trying to remember just who swore to me it was a mechanical failure to the cam ring? Drawing a blank, but I have asked in past postings what neg effect if any would hi-pops have on the life of the cam ring because I read somewhere that the excessive pressure required to pop the the injectors could damage the cam ring, thinking I fell for some BS along the line.


As far as I know it's just a theory that higher pop pressures could contribute to shortened cam ring and roller life. It kinda makes sense, if these components have a finite wear lifespan that a higher operating load would shorten that life. But, it's still just a theory... At least it is until someone runs a number of side by side bench tests using stock and uprated pop pressures to determine whether there is a difference in durability. ;)

Another question when using higher pop pressure injectors is what effect that might have on the FSD. BETA (FSD Cooler manufacturer) found that a failed lift pump caused the FSD to generate more heat because it had to work harder. Would higher pop pressures cause the FSD to run at a higher temperature?

Jim

[Robyn]

I am wondering what Peninsular uses in their 300 HP units that are running the hig pop marine injectors???
I realize the DB2 is somewhat different but the cam ring and rollers are are still present enven in the DS4

Just currious

Robyn

[DA BIG ONE]

I am wondering what Peninsular uses in their 300 HP units that are running the hig pop marine injectors???
I realize the DB2 is somewhat different but the cam ring and rollers are are still present enven in the DS4

Just currious

Robyn

I've heard of 6.5td making 350 HP @ crank using DB4, for over the road I'm thinking some cooling mads might be needed.

[DA BIG ONE]

Page 6-2273 of the 1998 GM service manual discusses P0251 in more detail.

The DS4 fuel injection pump's main shaft turns at the same speed as the engine's camshaft (1/2 engine speed). So, a signal generated by the OES could be used to indicate camshaft position. The Duramax also uses a cam position sensor as part of its EFI system, but it reads a notched wheel mounted onto the face of the camshaft.

The distance is so small between the OES emitter and sensor that the fuel would have to be nearly opaque to prevent light from shining through the coded disc. So, I wouldn't necessarily agree that dyed fuel or fuel treatments could affect a typical and normally operating DS4. I wouldn't worry about dye used in the 2-cycle oil. Air in the fuel system is mentioned in the manual as a potential cause for a P0251 because a bubble could optically interfere with the light.

Also, the GM manual suggests that for a P0251, the fuel injection pump would need to be replaced once eliminating a possible wiring problem. If the problem persists, they then suggest replacing the PCM.

Some here have replaced a defective OES without removing the DS4 from the engine. There is a calibration procedure that needs to be performed at a pump reman facility when installing a replacement OES, so it would take luck, trial & error, patience, as well as a good understanding of how the OES contributes to EFI to be successful when doing it in the truck. :)

Jim

I happen to have my factory HD PCM, thinking of cutting back on boost and trying it out for awhile.

[xtrempickup]

wow well eveyrthing i thought i needed came. Cooler, new pmd and 6 ft cable. I guess i never asked how invovled getting the old one out was or the procedure. let me guess this is an all day job? i need to remove the intake manifold to do this? then i guess remove the gaskets etc and if this doesnt fix it i just spent a whole lot of time on this thing. wow i think i should have asked how much work and what was involved in changing this thing

[JohnC]

Leave the old one where it is. Use a long thin screwdriver to release the lock on the connector and pry it loose, then pull the wire up to where you can connect to it.

[xtrempickup]

my connector that is on the one thats on the IP is facing toward the rear of the truck. i dont think there is anyway to get at it. i guess i could try again. i guess isnt worth a shot since i cant even see it

[xtrempickup]

ok thanks John, was able to get the old plug off the IP mounted pmd and the new one connected and is in the front bumper nostril. just have to do something to old it there havent figured out what just yet as there isnt much to mount it to or tie it up to. my cooler is about 7in x 5 and was just able to get it in there, now comes hold to get it to stay in one place. i managed to rig something up til i can mount it better

[DA BIG ONE]

At bottom of bumper are holes to mount air dam these are good locations to mount your cooling plate too behind one of the openings. Thinking slightly longer bolts, small "L" bracket and you should be good to go........

Good luck!