FSD, PMD, PMD, FSD -or- It's 10 pm - where is your FSD? [Archive]

gmctd

11-24-2003, 17:32

How I learned to live with the FSD\PMD, and love it.

This post is to cut thru the big words and techno babble, detailing simple instructions for repairing and re-using a failing FSD\PMD module.

Two distinct failure types occur -

1. Shuts off, no restart - this more than likely will require FSD replacement.
Try the procedure before replacement.

2. Shuts off, restarts
a. shuts off, immediate restart
b. shuts off, delayed warm restart
The procedure will likely recover this FSD failure.

I have over 2 years on a recovery repair made in late Summer '01.
Several DP members have reported recent repair success.
BETA, an engineer and DP member in Sweden, also attests to several long-term recovered repairs.

Refer to "IT'S 10pm - I'VE FOUND MY PMD" post by TODDMEISTER for FSD\PMD photos.

Remove the FSD module from the Inj Pump, or the remote FSD Cooler heatsink.
If the flexible thermal pad is stuck to the FSD, carefully remove it.
You will note two rounded parallelogram shaped wells in the aluminum side opposite the Stanadyne label.

The two transistor drivers are in these wells, under black plastic covers.

With a flat-blade screwdriver, carefully pry the black plastic cover off each transistor.
You will see two 1/4" nuts securing each transistor, one at each end

Loosen each nut, then run it down to the transistor case finger-tight.
Tighten each nut 1/2 to 3/4 turn from that point.
This will restore internal electrical connection, and thermal transfer.

Re-assemble the FSD module and thermal pad to the IP or Cooler heatsink, tightening each Torx mounting screw 1/2 to 3/4 turn past full contact with the plastic case.
Or, follow the instructions supplied with the Cooler.

A new htp insulating pad is available which prevents loss of thermal conductivity when FSD mounting screws loosen.
An article on this new htp is currently in the Member's Area.

Refer to "IT'S 10pm - I'VE FOUND MY PMD" by TODDMEISTER for photos of FSD\PMD.

Should you choose to attempt this repair, please note it in this post, along with success and\or failure.
Also note the vehicle year and model, and Stanadyne part number - 30214, 34264, 34583.

Mine is '89 GMC 3500 with transplanted '95 6.5TD, FSD #34583.

[ 12-05-2003, 08:38 AM: Message edited by: gmctd ]

Randee of the Redwoods

11-24-2003, 17:39

Where's my FSD? Sitting on my kitchen table. Well, the one of Ebay anyway.....

GARY PAGE

11-24-2003, 17:53

This is a 95 3500 Dually. The FSD cooler is now mounted in the radiator support just in front of the drivers side battery and behind the drivers side head light. Plenty of room and there is fresh air circulation there, there a hole in the support there and fins face the air flow. There is some heat transfer from the radiator and I placed a heat shield, that space age aluminum foil stuff with air gap to stop the radiator from venting on it. It is much cooler that the manifolds mount and has less to vibration as well. One touch tells the difference.

DAVE FERENCZ

11-24-2003, 21:00

Hey Redwood ebay what did you pay What did you get? Wher you gunna put it?

moondoggie

11-25-2003, 04:18

Good Day!

Would this topic essentially be a summary of FSD\PMD - BFD? I follow that one as closely as possible.

The work everyone has done on this issue is wonderful. I sure wish I hadn't tossed my dying FSD. It had symptoms that I now know are classic indications of loose drive transistor hardware. Sure, maybe that wouldn't have fixed it, but maybe it would have..... In my little dream world, I'd have liked to have been able to participate in the work done in that topic.

Thanks so much for sharing your wisdom. It keeps my truck running - I wouldn't be able to keep this thing without the Page & its contributors.

Blessings!

Brian Johnson, #5044

gmctd

11-25-2003, 04:41

That is correct, Moondoggie - this post is for those folks who may not know a transistor from a trans sister, but would like an option to purchase\replacement only.

Hopefully it will also provide more collateable failure data for reference.

The "FSD\PMD - BFD" post can be used for more technical info if available.

Thanks for your continued interest.

Marty Lau

11-25-2003, 07:55

I did the repair.

1995 6.5 C-2500 "S" engine
Stanadyne 34583
Mounted on BETA Cooler on Intake

Since repair died once, and then died and restared on own on first trip of repairs. Since no stalling but still getting periodic SES light.

About 120 miles since repair about half towing 5,000 lbs.
Have Heath relocate kit coming with FSD & Extension, I'm going to mount that sucker down low away from all heat sources and keep cooler and fix FSD for spare.

I also noticed last night after towning I checked the FSD and Intake manifold. The FSD was cooler since tightening everything and the manifold still very warm.
GMCTD, thanks for all your help over the time you have been posting here, I for one appreciate it.

moondoggie

11-25-2003, 08:24

Good Day!

As I

gmctd

11-25-2003, 09:33

Are any DTC codes setting with the SES, 16ga?
That data can point to a specific failure in the loop.

Autozone, JCWhitney, etc, sell the 30-40 buck EQUUS code reader - displays codes on 4 digit led display, for those needing a handy reader.

patrick m.

11-25-2003, 16:28

i got the "kit" from JK, put it in front of the driver's side batt.
the old one is still on the pump and was not giving trouble (thought i would be better off doing it now and having the spare on the pump).
did this approx 2months ago.

95C3500Cheyenne

11-25-2003, 17:02

The information here is most informative. I recently purchased 95C3500 LB Cheyenne. I just turned 130k. I have had the stall problem three times and luckily have had a restart. I purchased the truck with 123k. I have changed the oil(3 times), oil filter(3 times), fuel filter(3 times), flushed radiator, flushed dif, and flushed tranny and replaced filter.

My problem with the stall seems to be in the area that you all are addressing. I have had the SES light approx. 4-5 times and it goes out after a while. Also, if i really get into the throttle, she jerks a little (like a misfire but this is a diesel).

I am looking for help with regard to this problem with the FSD. I am not a mechanic and with a 1 year old and one on the way my spare time to investigate,mechanic is non exisitant. I need photos, guides, etc. to help my mechanic with the mods.

Thank you for any help.

Chattanooga, TN

Frank Youmans
Dillard Smith Construction

Randee of the Redwoods

11-25-2003, 17:26

Hey DAVE- This is one of the 2 "non functioning" units I bought. One was said to cause the motor to run rough, the other was specifically stated to have set a code 1217. If I remember correctly, the first one I messed with was the code 1217. Everything seemed fine and dandy. Nothing unusual about it. I retightened the transistor screws to a common uniformity and all seems well. If you are having a problem with yours now, this would be a good one to try out. My guess on the FSD screws is to screw them down just until they seat, then go another 180 degrees. This should be plenty tight plus even torque across the unit. The pump it came from seemed ok but takes considerable effort to turn so it may be junk. The other pump turns much easier.
I picked up 2 pumps with fsd's for roughly $75 each delivered. I think that's a reasonable price to pay for the research. I'll be willing to pay more as the results come in.

CaseyR

11-25-2003, 18:42

Uh, GMCTD, what's with the Equus GM Code reader, it says it causes the trouble code to flash on the SES light - sounds like a much more expensive version of the paper clip. What am I missing here?

I looked at the details for it on:
http://www.autobarn.net/eqgmcodread.html

gmctd

11-25-2003, 19:02

EQUUS, iirc, offered three versions -
- a simple ALDL short to trigger the codes to the SES display, about 20 bucks
- a led display reader, with digital readout, about 40 bucks
- and a 160 bucks version, that maybe stored the codes for show and tell

Check out the JCWHITNEY website - they offer all the versions - Autotap, Auto Xray, Equus, etc

Guy at work was asking about reader-scanner differences, this morning, but time was not available to in-depth review them.
Told him to check back tomorrow, when only us peons would be around after 10-11 am.

gmctd

11-25-2003, 19:11

Can anybody out there post a few pics -

of the FSD\PMD on the Inj Pump

several views of the FSD, detailing mounting screws, driver transistors and kep nuts, etc

Thanks

ToddMeister

11-26-2003, 04:14

Hey gmctd, I've been looking at my two ebay aquired pumps and have the PMD's off them. The nuts weren't real tight on the pmd's at all. I'll take some pics this afternoon when I test them out on the FSD cooler. I'll edit the pics and post links hopefully by this weekend.

I have a 95 pump with the 30214 PMD and a 97 pump with a 34583 PMD. They both turn easy. Heck, maybe just the PMD's needed their nuts snugged up.

gmctd

11-26-2003, 04:32

Good news on the pics, and good luck on the FSD's, Toddmeister. Thanks

Also, just popped over to the JCWHITNEY site meself - looks like EQUUS discontinued the digital reader, offering only the entry level blinker, and an OBD-II digital display reader @ 170 bucks.

Sincere apologies for the mis-info, folks.

patrick m.

11-26-2003, 16:05

Frank, your engine miss is almost certainly the oil pressure switch.

the stalling, being that you have a '95 model, could very well be the ignition switch. If it is, you will be able to tell by taking carefull note of what the dash warning lights do when it stalls.
If the warning lights come on (s.e.s, service throttle, w.i.f., etc) as soon as engine dies, not ign switch, if none of these lights come on right away, ignition switch is likely the problem.

gmctd

11-26-2003, 16:59

Adding to PatrickM's post, check the lift pump under the truck, driver's side inside frame rail in area below driver's seat - should be vibrating when engine is running.
If not, check the fuse by the OPS relay on the firewall, then the OPS switch.
This may give DTC35 Inj Pulse Width Short - it will cause "misfire" symptoms under load.

Also, please post your SES DTC codes for further troubleshooting.

ToddMeister

11-26-2003, 17:58

Well, both "ebay IP" PMD's worked when I mounted them on the FSD cooler. :D

The transistor nuts were kinda loose on my new PMD that was purchased with the FSD cooler. I snugged them up, too.

I also took some PMD pics that I will edit and post links to by end of the weekend.

Happy Thanksgiving everyone....

BETA

11-27-2003, 10:09

Stainless steel is not used in switches, relays, etc., as a contact material. Stainless steel is not stainless by itself, it is the chrome oxides on the surface that create this condition.

If you machine stainless steel, you have to wait at least 24 hours to allow the chrome atoms to oxide, before you do any corrosion test on the newly exposed surface.

The chrome oxide layer or the

Bill Volcko

11-27-2003, 12:32

GMCTD,
I tried your technique to resurrect a failed FSD. No luck. My stalling and intermittent restarting was definately caused by a bad FSD. After new FSD installed truck started right up. Shut sdown and reinstalled old FSD..no restart. Put in new FSD, and started right up. This was after I retorqued the nuts on the two transistors on the old FSD. By the way, this is on a '95 3/4 ton chevy p/u. Old FSD # is 34583 same as new one. Mounting screws on old one were only finger tight. I'm waiting on a FSD cooler from Kennedy right now. Thanks for the help.
BV

gmctd

11-28-2003, 09:01

Thanks, Bill, for posting the failure.
Not all Modules will recover, but the procedure is worth trying on each one.

BETA -
Excellent information, as always. Scientific data explaining my simple statement - stainless is not a good electrical conductor. Thanks, again.

To all - I do appreciate your contributions to defining the problem, and a possible resolution.

Keep posting - it is what makes 'the Diesel Page' my favorite website.

KrisHull

11-29-2003, 20:58

This past week, after I read this post, I decided to try out the "fix." I had an FSD that I tried on my truck after I tightend the nuts on the transistors. Truck would not start. So I thought since I had a bad FSD already I could not hurt it anymore. Loosened up the transistor nuts and then moved the transistors around with a screw driver. Then I retightend the nuts, and tried the FSD again. Truck started and ran fine.

kowsoc

11-30-2003, 06:20

That makes me think that the solder joint(s) might be broken where the transistors are soldered to the PCB? I'm still not comfortable with this FSD thing but all the information is definitely making it less of a mystery. Keep posting as I for one find this very interesting. My spare FSD is still staying in the glove box though. smile.gif

BETA

11-30-2003, 07:59

Bill & Kris

Very interesting!

Let us know if you find out what's buggin'

rjwest

11-30-2003, 13:20

I agree with bad solder joints on transistors,
Re torquing nuts will put stress on soldered pins
" fixing " bad solder joint....Temporarely..

I attempted " transister replacement"

Transistors can be " pulled " from FSD after
nuts are removed....( indicates a poor solder joint ? }

I have not been able to figure an easy way to expose
solder side of FSD, If I could get at the solder
joints I would try mounting the Transister
externally For cooling and replacement.
Assuming they are failing component....

gmctd

11-30-2003, 21:01

From "FSD|PMD - BFD"

Here is a suggested procedure for working with the FSD.

If you have access to a Pace or equivalent desoldering system:
The tips are 0.125" od; one tip is about 0.120 id.

Using this tip in the heated tool, lightly force it down into the potting compound, such that it will descend over each transistor lead.

Do this incrementally, without vacuum - the heat will powder the compound, and you can blow it out with shop air, or brush it away.
Continue this until you reach the pcb circuit pads - Base is 0.062 diameter, Emitter is 0.125 (approximate).

Caution - the PCB is only 1\4" below the FSD cover.

Change tip to the 0.030 id, desolder the connections.
Use resin soldering paste, and reflow resin core solder, if necessary.
(That's 'rosin', for all us shade-tree techs)
The potting compound also covers the pcb back side, and will prevent easy solder removal.
When you can see full clearance between the leads and the plated-thru pad holes, the transistor can be removed.

It may require some force, due to the potting compound settled into the Base\Emitter lead bores in the heatsink.
I used long-nose Vise-grips lightly clamped on the driver cases, with a flat-end allen wrench to push the leads thru.

The potting material can then be carefully drilled out to provide wiring access.

The drivers are oriented 180deg opposite, for easier paralleled Base-to-Base and Collector-to-Collector connection.

I do not think remote-mounting the drivers away from the Module, and\or higher wattage devices, is a solution.
The above procedure, or equivalent, should enable further testing in several directions, if desired.

[ 12-04-2003, 04:52 PM: Message edited by: gmctd ]

kowsoc

12-01-2003, 05:43

Rjwest, yes I agree that if the problem is a solder joint(s) on the output transistors then the ONLY reliable fix is to repair the connection. Changes in temperature will continue to work on a damaged connection until it becomes intermittant again, IMHO. I remember talking to a VCR repairman who said a lot of the problems (on my particular VCR) can be linked to a cold solder joint somewhere in the circuitry.

Relocating the output transistors would be a great test. Since the transistors are the big heat generators, a cooler for the FSD would not be neccesary anymore. If you could remove the transistors with the above mentioned method and solder lengths of wire in place, the transistors could be mounted anywhere (on a heat sink of course). This would then tell us if the common problems for the FSD are output transistor related or something else logic related deep in the epoxy. If it did turn out to be transistor related, then bigger transistors could be used. Could this be the cure?......hmmmm. :rolleyes:

Marty Lau

12-01-2003, 10:20

Originally posted by gmctd:
Are any DTC codes setting with the SES, 16ga?
That data can point to a specific failure in the loop.

Autozone, JCWhitney, etc, sell the 30-40 buck EQUUS code reader - displays codes on 4 digit led display, for those needing a handy reader. I cleared the codes and check after that, The engine is setting DTC #35, 33, 32

Also engine started the stalling bit again, got the Heath Isolator kit last week so now I have to mount it and get the 6.5 on the road again.

Sorry it took so long to reply back but had very important things to do over the long weekend. Hunting.

morgan

12-01-2003, 14:44

Wow, we are all suffering from this. What a PITA. GM should be begging for forgiveness.

Some of you electrical guys tell me: would a "dielecric grease" (clear grease in a small tube), "electrical cleaner" (spray can, quick to evaporate), or a "heat sink compound" (small tube from Radio Shack) help with any of these connections?

I've put the dielectric grease on other fuse applications and not been totally successful with it. Older Volvo car fuses (ceramic fuses with metal strips that corrode easily).

Sounds like we're going to apply a similar version of "Dr. Lee's battery fix" to the FSD's. I've been praying for a solution. It's a heartbreaker. My truck was the first to be hooked up to a Dyno at a local hotrod show recently and it kept stalling out. I was very embarrassed, and they folks took sympathy on me: no charge.

Mine stalls at various speeds and conditions. Usually can be restarted while still rolling, but normally have to pull over after 2nd time or so. I have found that pouring cool water over the FSD will get me home.

I'm going to try the nut-rotation method soon. What about the two plastic solenoid covers on the FSD? throw them out? I did.

Randee of the Redwoods

12-01-2003, 14:58

If it is a cold solder joint problem, or even an insufficient amount of solder on the joint problem(like some RCA tv tuners), then the only true fix is to resolder them, maybe with a higher heat solder. Problem solved. After that, there should be no need for coolers and relocators and such.

gmctd

12-01-2003, 16:32

16ga Those DTC's - 32,33,35 - seem like they might be engine connection or grounding problems.
That's EGR, BARO sensors (+5v power), and IP Pulse Width Response Time Short (+12v power).
Might try disconnecting, inspecting, and re-connecting all plugs at rear of engine, behind fuel filter.
About four or five there, then do all connectors in engine bay.
Check harness ground points while you're at it -"winterize" the wiring, so to speak.

Dunno about the covers, Morgan - many trucks have gone over 100k miles with them installed. I pitched mine, but filled the cavities with white silicon heatsink compound, thinking that would help prevent further oxidation. I'd have to pull the FSD off the IP to tell, tho.

Remember - back the nuts off, run them down finger tight, then enough to put a few inch pounds torque on them.

BETA states 1\8th turn, so try that first.

I did about 3\4 turn 2 years ago, but won't know if the drivers were mechanically damaged until time to remove the FSD.

Maybe someone could try that with an inch-pound torque wrench, then post results. ???

[ 12-01-2003, 03:43 PM: Message edited by: gmctd ]

Marty Lau

12-01-2003, 16:49

GMCTD;

I will clean all connections and grounds here shortly I am going through a bunch of maintance items, (injectors, glow plugs, PMD Isolator,transmixer service ect)
so I will add the electrical to list of items to do.

Tom C.

12-01-2003, 18:53

Had a fairly new FSD mounted on a cooler that I thought was toast. Removed FSD from cooler, tightened up the transistors and remounted using heat transfer compound. Plugged the FSD into the IP and it works again! Don't even have the cooler remounted again. I didn't have much faith in the "cure" so I just laid the cooler up in all the other stuff on the left front fender, Guess I will have to get it remounted now.

TomC.

Marty Lau

12-04-2003, 09:02

Well I burned the midnight Diesel last night and mounted the Heath PMD/FDS Isolator on top of the frame crossmember under the driver side near the lift pump. It sould be a much cooler location than on the Intake manifold and with all do repect to Beta I hope it last much longer than 24,000 miles that last install did. :( In my opion a Beta cooler on the intake does not preform as well as the pump mounted install. Yesterday coming in to town the truck stalled 9 times in 11 miles :eek: Last night going home I got about 15-18 stalls in 11 miles even with pouring water 3 times on FDS cooler. :mad:

I located several grounds and will be cleaning them tonight and unconnect and reconecct the wire plugs. I cleared the codes this morning and the truck ran last night on test drive flawless and this morning flawless. Since I have 2X4 I had no skid plate to mount on. The cable supplied by Heath is like 6 foot long and was plenty long enough to locate the heat sink under drivers seat on top of frame crossmember. I drilled a couple of holes in the flange of the crossmember set the Issolator on top of the crossmember and with the spacer nuts provided by Heath reversed it made for a secure install up and out of the way. I tie wrapped the cable at about six spots on the run.

I bought the Beta cooler year and half ago from Gomers/US Diesel $345 with modual no cable aviable, JK kit with cable $510 plus shipping, Heath Issolator kit $379 includes heatsink, FDS/PMD, Resistor and 6 foot cable and instructions and Bill ships it and he discounted it a bit since I bought some other stuff with it. :cool: Time will tell how good a install this is but it has to be better than on top of an engine heat pump that vibrates.

[ 12-04-2003, 08:14 AM: Message edited by: 16ga SxS ]

Marty Lau

12-05-2003, 11:18

GMCTD;

Worked again last night on the truck, I clean all grounds that I could find and get too. There is like 4 ground terminals on the back of the engine on a bolt. Took the first nut off and then noticed a mounting bracket for the Automatic transmission fill tube prevents get the remaining nut and terminals off for cleaning. :confused: why would GM do such a thing? I pulled apart all the plug connections sprayed them with contact cleaner and put them back together. Also did that with the connections on the sensors, which I discovered the MAP sensor lose and in poor conditions so I'm replacing that. I also discovered the vacum line going to wastegate controller had several breaks and worn spots. The vacum line had wear spots from the plastic loom the was installed at the factory to prevent wear, go figure. So, any way replaced the wastegate controller with the Heath Controller.
The truck now has boost again.......YAHOO!!!! :D :D

gmctd

12-05-2003, 14:16

Congrats, 16ga.
It is a good feeling, when things get right. Other than the new Heath Cooler and Boost Contol, it's just yearly preventive maintenance as the ole rig starts to get long in the tooth.

Did GM put the grounds under the trans filler tube, and other brackets, so (1)they would not be overlooked during a trans overhaul and other routine repairs, or (2), so an overzealous mech would not rip them out during a tightening manuever?

Or, was the dipstick tube the next-to-last part to go on? (The last, of course, being the nut!)

Only the Shadow knows.....