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

[gmctd]

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]

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

[GARY PAGE]

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]

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

[moondoggie]

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]

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]

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]

Good Day!

As I

[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.

[patrick m.]

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]

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]

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]

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]

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]

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]

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]

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.]

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]

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]

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

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....