View Full Version : FSD: Remote or pump mounted survey
rapidoxidationman
03-23-2004, 22:05
I'm curious: How many of y'all have the fuel solenoid driver mounted on the pump and how long has it been there? Mine's got over 80,000 miles on it and is going south. Now how many have the remote mounted driver and how long has it been there? In my quest to learn more about the driver and the best way to handle it, the pump rebuild shop I spoke with was adamant about keeping the fsd on the injector pump where it has the active cooling source of recirculating diesel fuel, rather than remote mounted on a heat sink where it (in his words) WILL overheat and burn out. He's replaced a lot of fsd's whose lives have been cut short because of burnout caused by the remote mount setup. I'm pretty interested to see the survey results.
Regards,
Rapid
sturgeon-phish
03-23-2004, 22:08
To the best of my knowledge, original FSD on pump with 73,000 mi.
I have had to replace the FSD twice, and the entire pump, with the FSD attached, twice. In other words, my 6.5 has seen 4 FSD's. The first FSD only replacement was at about 40,000 miles. My pump failed at 14,000 miles, and GM would not replace it under warranty, saying I had gotten bad fuel. So the 1st FSD replacement only had about 26,000 miles on it. The pump failed again at 60,000 miles, and it was replaced, along with the FSD, under warranty. The FSD failed again, at 120,000 miles. so I mounted it remotely. I've only put another 8,000 miles on since that, so I guess time will tell. I have read about more FSD failures in the stock location, than mounted remote, so far, plus it is so much easier to get at now. I also purchased a spare FSD. I got both the spare, and the one on the truck, from eBay, used, for about one-third the cost of a new one.
rjschoolcraft
03-24-2004, 04:24
If you read some other threads in this forum, you'll see where I had over 120,000 miles on my pump mounted FSD. It started failing last week (intermittent stalling). I now have a new FSD mounted on a cooler behind the driver's side headlight in front of the battery.
The mechanics comment about "active cooling of the circulating diesel fuel" shows that he doesn't understand heat transfer very well. There are basically three types of heat transfer: conduction, convection and radiation.
Conduction is heat transfer through a solid or liquid.
Convection is heat transfer from a surface of a solid or liquid to another liquid. For instance, transfer between a solid and the surrounding atmosphere. Convection can be further broken into two types: forced convection and free convection. Free convection occurs due to temperature gradients in the surrounding fluid. In the example of a hot solid block above, the temperature of the surrounding atmosphere near the block will increase. Hot air rises, so a natural circulation of air begins, actively cooling the block. Forced convection involves artificially circulating the liquid with either a pump or fan to force it past the object to be cooled or heated.
Radiation is how the sun heats the earth. This can happen in a vacuum and needs no medium to transfer through. Hot objects radiate heat through electromagnetic energy to another object.
All three forms of heat transfer depend heavily on the difference in temperature from the heat source to the heat sink and on thermal coefficients...properties of the materials involved. The convective heat transfer coefficient is heavily influenced by the velocity of the fluid as it circulates past the heat transfer surface.
When mounted on the pump, heat from the FSD must transfer by conduction through the base of the FSD into the heat transfer pad, through the pad and into the pump body. The forced convection transfers heat from the pump body to the fuel. This rate of transfer (and whether it is from the FSD to the fuel or vise versa) depends on the temperature difference between the FSD and the fuel and the thermal conductivity of the various metals in the path as well as the convective heat transfer coefficient at the interface with the fuel.
On the cooler, heat transfers through conduction into the cooler in a similar manner as when mounted on the pump. When sitting still, the primary remover of heat is free convection. When moving, it is forced convection. The rate depends on the difference in temperature between the FSD and the surrounding air and on the coefficients mentioned above, which will be different from the pump mounted situation.
I'll leave it for you to decide which provides the better mounting.
In those other threads that I mentioned earlier, I took the position that I would not move the FSD until some failure occurred: if it aint broke, don't fix it! Now that a failure has occurred, I opted for the cooler in a remote location. The ease of access to the FSD is a major consideration now.
lupey6.5
03-24-2004, 05:01
the pump would provide adequate cooling if it were on a test stand and not in the stock location. i mean the intake manifold is cast w/ a notch in it to keep it from touching the pmd,to make things worse gm put a big cover over the middle of the engine for looks but it works like a blanket. i think that the shop likes your repeat business and doesn't want to loose you. the pmd is a delacate piece of electronic equipment, you would not see a engine mounted ecm would you. i ran without the engine cover but pmd died anyway. replaced it but put it on a piece of alum. heatsink about 5"x7" with 2" fins. mounted it on the wheel well near brake booster. 30,000mi. without a spit or sputter or stall and i check it all the time and it never gets hot to the touch even during mid summer towing. my vote is remote!
Dvldog 8793
03-24-2004, 05:28
Ronniejoe makes very good points! One other thing to remember is that when you do mount it on a remote cooler The mounting surfaces HAVE to be IDENTICAL. Some people say that the sink has to be milled perfectly flat. That's great if the FSD is flat. I checked mine and it was not as flat as the heatsink that I have. If the mating surfaces are not true to eachother you loose allot of efficiency. After correcting this and useing heat-transfer paste and torque the mount to spec(don't remember :confused: ) I think the heat sink is much better than the pump under MOST conditions. I have had my FSD mounted remote for about 100,000 miles. No problems. My pump went south with 125,300 miles and was replaced with a new FSD under warrenty :D :D :D
The Dealer that did the work said WOW what a great idea, how come GM didn't mount the FSD like that?
My 2 Cents.....
L8r
Conley
Bobbie Martin
03-24-2004, 05:39
Originally posted by rapidoxidationman:
rather than remote mounted on a heat sink where it (in his words) WILL overheat and burn out. And he is absolutely correct. Trouble is, they don't do much better if you leave them on the pump. Ask him if he has ever replaced a bad PMD mounted on a pump. My guess is more than one. From my experience they go bad no matter where you put them. However, if you remote mount it its easier to change when it goes bad. In my mind, that feature alone makes remote mounting the best choice.
Dvldog 8793
03-24-2004, 05:54
Mr Martin is also right. When they replaced my pump they were good enough to take off the new FSD and give it to me. Also they gave me the old pump mounted FSD that supposedly tested good. So in my tool box I have one new and one old FSD. I would think that no matter what you do eventually the FSD will fail, just the nature of the beast. But as stated it sure is easier to change on the side of the road when it's by the fender!
Wheat Whacker
03-24-2004, 19:27
I have one still mounted on the pump that still works and acts as my spare should I need it. The one I use is mounted on a cooler and will be moved into the cab if I ever get the time to do so. One thing to remember is to retorque the mounting screws every couple months as they WILL loosen up. I know this from personal expereince and it cause my last one to fail.
Marty Lau
03-24-2004, 21:41
1st blue lable pump changed at 28,000 changed PMD after over 100,000 on replaced green lable pump and used a Beta cooler on the intake about 30,000 miles took off a Beta cooler and put a Heath PMD Isolator on under truck on top of frame cross over under cab. 7,000 miles. So I'm on #4 PMD/FSD second pump, hope pump goes many more miles. (wheres some wood oh I'll use me head)
My Opinion from being on this site since 1996 is that....either mount it back on the pump or get it in a cool spot not on the intake manifold as many of cooler/chillers do. In my observatioon it seems like you can get 75-100,000 on the pump mount 25,000 to 40,000 on intake manifold. I know Beta may disagree but I paid my money and took my chances. It also seems once you get your first stall tighening the nuts buys some time but
you better get an new modual as sooner or later it will get worse. If you tighten the nuts before you start getting stalls you maybe okay your modual maynot be "fried".
BTW any word from Beta on the PMD replacement arena seems to have disappeared about that?
If the PMD under the truck goes I'm going to build me a little PMD wrench and replace the pump one. Also report your failure to Highway Safety maybe they will force a recall if enough of us do this it is a dangerous situation.
DickWells
03-27-2004, 07:04
HI Rapidox: I had my FSD remote mounted on a JK cooler and home-made harness for two years without failure. I mounted it in front of the driver's side battery. I say had, because I thought last week that the FSD had gone away again, and bought a new one. No fool like an old fool. Turned out to be a broken wire to the optical encoder, near the IP. So, I have a new FSD on the cooler, and a two year old one for a spare!
I would never put a PMD back directly on the pump. The original PMD was always too hot to touch whenever I stopped. Now, this may be of interest. I used to feel of the FSD down in front of the battery, and thought it was hotter than it should have been. Well, last week when I changed to the latest one, I put in a bunch of alluminum foil as a shield between the battery and the radiator tank, to seal off that passage against hot air comming from the engine compartment. Well! Now, every time I reach in there after a run, I can't believe how much cooler it's running. Seems to be getting it's air from around the bottom of the headlight and behind the grill cross-member likeI had intended from the first.
For what it's worth, and good luck.
Dick
rustypig
03-28-2004, 20:15
2+ years on a remote heat sink. "Tard engineering" can make a lot of sense when OEM designs obviously stink. Just MHO though.
rapidoxidationman
03-28-2004, 20:38
Dick Wells from LUHS? Guy, class of '84...
Great minds think Diesel
Rapid
Has anyone rigged a temperature gauge on the pump/FSD to see just how hot it is when it is running? Anyone seen figures published on the remote mount that gives temperature figures. All I have seen is anecdotal stuff with no figures to back anything up.
Would some Lock-Tite or similar on the mounting screws help secure things a little better?
195deg ECT
8psi boost
180deg IAT
1000deg EGT
137deg Fuel temp inside the inj pump
FSD\PMD re-mounted on pump 2001
1/4 tank
65mph
2200rpm
climbing hills
And, still - no.... :cool:
[ 03-29-2004, 08:50 PM: Message edited by: gmctd ]
Well I can't top GMCTD for data;
My wallmart battery operated outside temp probe stuck to top of FSD with gum runs around 100 deg
or cooler when A/c is on. FSD is mounted right above the Diesel Pedal....with A/C air blowing on it.
patrick m.
03-30-2004, 17:01
behind driver's side headlamp. fully operational spare mounted on pump still ;)
Taking a hard look at mechanical fuel injection for my 97 with 82,000 miles. First PMD failure at about 70,000. Appears to be headed south again. Not sure, even if for free, I want my "friends" at the Chevy dealership tearing into the engine again.
I bought a 2003 Dodge with a HO cummings. Great truck so far. I kept the Chevy for commuting and farm use. I like the 6.5 engine. It's limited horsepower does not bother me. It is probably superior to the Cummins in that, under 2.000 rpm, it moves the pickup well. I just plain like the looks of the Chevy, as more of a classical looking pickup. At the time I bought it, it was hands down, the quietest and, I thought, the smoothest running of the big three.
I am looking hard into the remote mount PMD unit. Wondering if anybody has mounted the PMD in the cab. Not sure about the length of cable in some of the kits. Here in the southwest, the up to 122 degree F heat, with the engine heat could be an issue. I would think a mount, near the AC box inside might be a plus.
Anyway, with the 82 K miles on it, considering the Marine mechanical unit on it. Had a Mazda B2200 pickup with 2.2 liter diesel. Sold it with over 200 K on it. Injection system never touched. I am concerned about passing emissions with the mechanical injection unit on the 6.5.
GARY PAGE
03-30-2004, 17:41
Same as Pat M, behind driver's side headlamp!
In 40,000 miles I've been through 2 pump mounted FSD's and one mounted on the Beta unit bolted to the intake plenum. Recently purchased one of Bill Heath's units - he says I won't need a spare FSD once I install his; however, I'll never travel without a spare - It's sure nice to have a remote mounted unit that allows a person to swap the FSD in less than 10 minutes while broken down on the side of the freeway at 11:00 PM (speaking from experience). After I install the Heath unit I'll keep the Beta unit in the toolbox for a quick change, if needed.
Truck is still stock, 157,000, no problems.
Brother's truck has 237,000, also stock, no problems. Both 98's, HD engines, auto tranny, 4X4. Think you just don't hear of the ones that don't have problems.
:cool: K. D.
Rapid- I'd agree w/Ronnie that getting dogmatic about one or the other location indicates a level of prejudice that logic can not cure. Certainly the heatsinks can scavange the heat, and ignoring that for some prejudice don't compute. FSD is a piece of equipment, and all equipment breaks eventually.
Undeniable advantage of remote is servicability and any tech that ignores that leaves me stupified as well.
Some have great luck on the pump and More Power to them. But it's more PITA to change there.
I've run my rig, hopped out & hit the cooler plate & FSD w/infra red thermometer: 135 degrees at hottest on a 100 degree day (behind headlight). I know that's cooler than max. OEM condition without running any tests. To the extent failure is heat related, a cooler will do the job.
I would have to agree with that, 100%.
Convenience and cooling would be the deciding factors.
Of prime importance, whether mounting FSD on the IP, or on a heat sink out of and away from the thermally elevated blast from the fan, first check that the four 1/4-20 nuts on the transistor drivers are not loose.
In my case, a certain ease of mind is afforded by having a spare FSD mounted on a duplicated 'HFE FSD Cooler' safely tucked away in the toolbox. :cool:
Just built up a spare on a Pentium 4 CPU copper heat sink cooling unit with fan...(12$)
Now, if I powered the fan from the FSD power,
do you think it would cause " Voltage problems"
in PCM
???? maybe a multi contact sw, like NASCAR,
for aux ignition, I do get carried away sometimes.
Best would be a separate 12V supply, switched via thermostat on the hot spot of the heatsink set to ~125 degrees, w/a feedback loop that will set a DTC & SES for >150 degrees, and another DTC/SES for fan failure. ;)
Seriously, a separate fused supply for the fan would be best, maybe off the Fuel Shutoff Solenoid.
Or, off the battery with a 100deg Klixon thermal cutoff - opens below 100deg.
??
captaincrunch
04-05-2004, 11:33
I had a new pump/FSD combo OEM installed at 120K. Bought the truck at 89K and didn't see any records of it ever being changed before that.
At about 175K started haveing trouble. Periodically quit. Now, FSC cooler mounted on the left fenderwell. I can touch the cooler after running and it's just warm.
Plus, if it does go again, it's an easy change.
markrinker
04-05-2004, 11:51
I plan to mount my next FSD on a reworked Cray supercomputer board and run liquid NOS to it from a series of 50lb bed mounted supply tanks. I also plan to run a second liquid NOS line to the ECM as well, and overclock the whole damn works.
On demand, the NOS will be routed to the intake and be met with copious amounts of additional pure jet fuel injected through a second mechanical pump and set of injectors machined into custom forged cylinder heads matched to unobtainum pistons.
It'll be kinda like the AOL ads - I wanna go back to the Renassaince in my flatbed.
KIDDING GUYS!!!
DickWells
04-06-2004, 18:39
Hi Rapidox: Been off here for two weeks. Varizon cell phone power is not too great in a lot of locations.
No, I'm not an old LUHS grad. Just a Dear Old P.A. grad. Class of 1960. How is it that you come to know these things?
I just skimmed through all the above correspondence, and there's a lot there. By now the guy who posted the original question must be filled with data.
I still think remote is best, if you're sticking with the electronics. For myself, I can't wait to get my mechanical pump in there this summer while I'm back home in VT. Right now, we're in Punta Gorda, FL. Headed North this week-end.
BTW, do you know Andy Langerand? He and his son Mike are quite the wizzards on these diesels. I go up and see them when I'm home and need a shot of diesel enthusiasm and guts to get going on new mods.
Take care.
Dick Wells
gerickson
04-09-2004, 18:25
Guys,
Last August I replaced the 6.5 in my 96 K3500 with Kennedy
Well, heres my experience. My truck had a new injection pump and fsd at 104,000. It failed suddenly and surprise...not warranty(it was in '97) The green label pump and fsd lasted until a couple of months ago at 238,000 and again failed suddenly in the middle of a busy intersection. I put a heath remote fsd and I am sure of a long life as it isn't even warm after an extended tow when the old one on the pump was hot enough to burn your fingers.My wife is hesitant about driving this POS (her words) as she was at the wheel when it failed.I love the truck, but she is the boss.I hope this helps all.
Marty Lau
04-13-2004, 07:42
Originally posted by Mark Rinker:
I plan to mount my next FSD on a reworked Cray supercomputer board and run liquid NOS to it from a series of 50lb bed mounted supply tanks. I also plan to run a second liquid NOS line to the ECM as well, and overclock the whole damn works.
On demand, the NOS will be routed to the intake and be met with copious amounts of additional pure jet fuel injected through a second mechanical pump and set of injectors machined into custom forged cylinder heads matched to unobtainum pistons.
It'll be kinda like the AOL ads - I wanna go back to the Renassaince in my flatbed.
KIDDING GUYS!!! :cool: :cool: :confused:
Mark......I so want to go back in time!!!! ;)
[ 04-13-2004, 08:03 AM: Message edited by: 16ga SxS ]
For those mounting their FSD behind the driver's side headlight, what kind of bracket did you use? I have mine on its way and would like some idea of exactly how to mount it. While I am at it, I am going to put a thermostatically controlled fan on the heat sink for added cooling. The thermostat is set at approx 122 F moving 55 CFM. I can also get a smaller fan set at 104 F moving 35 CFM. Any thoughts? With regards to the fan, is there an unswitched power source nearby other than directly to the battery?
DickWells
04-17-2004, 18:08
Hi JT: I just made up three straps from aluminum bar stock. One quarter inch thick by 1" wide. Drilled and tapped them 5/16-18, and mounted them with stainless bolts, so that I could take out the battery and then remove the 3 bolts and the heat-sink FSD is in my hand. You're problem with that would be room for your fan. If you go with that location, don't overlook some sort of shielding between the front of the battery and the radiator shroud. I ran for a long time with nothing across there, and now that it's blocked off, I'm getting a lot less heat in the FSD, or the heat sink.
Hope you can find a really thin fan. That's a great location for the remote FSD.
Good luck.
Dick
BigDiesel
04-21-2004, 04:41
What about mounting the pmd/cooler combo inside of the air box? You'll get lots of airflow even when stopped in traffic, and it's a cool air charge as the airbox draws from the pass fender(outside of the engine bay). Correct?
Right, and good thinking. Some have tried it, but most folks drift away after finding resolution, here.
If the harness is routed in from the bottom, no worries about anything dripping in thru the entranceway, but seal it well, regardless.
Make sure it does not obstruct the air flow you're trying to take advantage of, right?
CareyWeber
04-21-2004, 13:18
I just got my new FSD/PMD should I use:
the mounting pad
heat sink mounting compound
mounting pad and heat sink mounting compound
The pads usually last for tens of 10k's of miles on the inj pump, Carey - I'd use the pad, wherever it is to be mounted.
After, of course, ensuring the nuts are properly tightened, 1/8th to 1/4 turn past finger tight.
How were they when you received the module - loose or tight?
CareyWeber
04-21-2004, 18:57
Originally posted by gmctd:
The pads usually last for tens of 10k's of miles on the inj pump, Carey - I'd use the pad, wherever it is to be mounted.
After, of course, ensuring the nuts are properly tightened, 1/8th to 1/4 turn past finger tight.
How were they when you received the module - loose or tight? gmctd,
I just checked the nuts I was able with just finger tip pressure on a 1/4" nut-driver I was able to tighten the nuts down between 1/16 - 1/8 of a turn. Do you think I should add another 1/8 of a turn to that?
I'd like to mount it back on the pump, but I'd also like to try to fix my old one (tighten its nuts ;) a bit), but I'd want to be hot swapable (to has a IT term).
I
As it's a new FSD module, Carey, 1/8th turn should be good. That's around 5 inch-lbs torque.
Use the supplied thermal pad, wherever you mount it.
Most folks report better service and peace of mind, locating it away from engine heat. Pros and cons of that have been hashed and rehashed many times here, as you know.
Best of luck with the repair, and your trip.
CareyWeber
04-22-2004, 01:30
Originally posted by gmctd:
As it's a new FSD module, Carey, 1/8th turn should be good. That's around 5 inch-lbs torque.
Use the supplied thermal pad, wherever you mount it.
Most folks report better service and peace of mind, locating it away from engine heat. Pros and cons of that have been hashed and rehashed many times here, as you know.
Best of luck with the repair, and your trip. Thanks
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