Driving home and the Yukon died on me. Just died and she fired right back up. Diagnostic check list is below:

1. Describe the problem you are having in detail:
Driving home on country road around 45 mph. Next thing I know truck would not accelerate. I looked down and gauges all read zero. RPMS showed nothing. Put truck into neutral and slowly came to a stop. Shifted to park and restarted truck. Truck ran fine the remaining 4 miles home. Truck started like there were no problems ever existing.
2. Year of truck/engine. 1994
3. Odometer reading (indicate miles or kilometers). 150608
4. Indicate the model number on the Injection pump (starts DS4 or DB2......). Not Sure (replaced at 75000)
5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD. 1500
6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) Yes, Vacuum line is pulled
7. Air Filter condition (visual check). Good
8. Fuelfile:///C:/Users/DENNIS%7E1/AppData/Local/Temp/msohtml1/01/clip_image001.gif (http://www.dieselplace.com/forum/showthread.php?t=42248) filter condition (freshly changed, mileage since changed). Right around 4000 miles
9. Location of PMD/FSD (http://www.dieselplace.com/forum/showthread.php?t=39436)? (ex. on pump/remote over intake, behind bumper). On Firewall with Heatsink
9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor). Extended wire harness
9b. Indicate the location and condition of the FSD/IP grounding wire. Not sure
10. Outside Temperature (C or F). __29___ °

11. Service Engine Light while running?- on/off/intermittent Off
11a. Service Engine light does glow during start/cranking/bulb check: Yes/No
12.Have you scanned for engine codes? Yes/No
12a. List exact results on engine codes (http://www.dieselplace.com/forum/dtc.php). 41 Brake Switch Circuit Fault This code has been there for a while

13. Condition of Battery terminals (removed, cleaned and tightened). Good/Yes
14. Known condition and age of Batteries. Less than 2yrs old
14a. Are batteries a matched set of same age? No and yes
15. Condition of Major Grounds (http://www.dieselplace.com/forum/showthread.php?t=157085) (removed, cleaned and tightened) Good

16. Does engine crank, or "turn over"? Yes
16a. Does engine start and run? Yes
17. If engine does not start- Crack injector line (http://www.dieselplace.com/forum/showthread.php?p=2188140#post2188140): do you have fuel? Yes/No
18. Does your Wait To Start light come on? Yes
18a.Number of seconds WTS light is lit. 8 to 10 seconds
19. Engine Cranking speed (if you have an accurate tachometer). Good

20. Are you experiencing Stalling? Yes
20a. Describe the event (upon startup only, down the road, hit a bump, etc...)
20b. Do you notice loss of dash or instruments? Yes, right after stall
21. Check turbo inlet and air filter for obstructions. Fine
22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?
23. Lift pump test (http://dieselplace.com/forum/showthread.php?t=39350) - Describe results. Can hear lift pump during shut down this morning

24. Upon cold start, does the radiator hose get hard quickly? Yes/No
25. Upon cold start, do you have excessive white smoke? Yes/No
26. Do you have excessive cranking time before the engine starts? Yes/No
27. Have you used the block heater? Does it affect engine starting? (only try for starting problems). Use the block heater overnight and get instant starts now since I fixed the block heater
28. Are all glow plugs in proper working order (http://www.dieselplace.com/forum/showthread.php?t=39182)? 150000 miles on them

29. During hard acceleration, do you have excessive black smoke? Yes/No
30. Do you have any unusual exhaust smoke issues? No
31. Turbo check out (http://dieselplace.com/forum/showthread.php?t=39368) - Pass/Fail
32. Indicate fuel that you are using: Bio-Diesel, #2 Diesel, SVO/WVO, other
32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system).
33. Are you using any fuel additives? If so, please list. 2 stroke oil Walmart brand
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? Yes/No Don’t know
35. Do you have any service history available that might pertain to the problem you are having? No, this was first time
36. Please indicate any modifications to the vehicle that might help us diagnose better.
Recently installed a #9 resistor old was a #7 (a week ago). Fixed my CDR valve. Recently did the OPS Mod (a week ago). Also cleaned all battery connections at this time. PMD was replaced and relocated by an auto shop by the previous owner. New PMD is located on firewall near the brake system. PMD harness looks bought and not custom made. PMD was replaced at 137000 miles.

Sounds like PMD,, if it was 95 or newer, I'd also say maybe ignition switch,, But When my 94 stalled and restarted,, a few times,, the crusie stopped working, then stalled more, then wouldn't start, PMD fixed it up. Anywhere under the hood, heatsink or not, subjects the PMD to heatsoak after the engine shuts off. As long as you have an extention cable. I'd try to take PMD off heatsink, and torque the little transistor nuts down, and remount, then move it outside of engine compartment. this may buy you some time, but if after you do this and it starts,, I'd really consider buyin a new PMD, buy only After you move it inside bumper area, or grille area.
I'd also suggest using standard 30W non-detergent oil, as it's cheaper then the 2 stroke and does as good if not better at lubing.

sounds like PMD

PMD harness is only like like 2 feet long. PO replaced the PMD on 9/7/2007 at 137,604 miles. Since then only 13000 miles have been logged. What is funny is after a 2 hour drive when I got home, I opened the hood and felt the PMD. It didn't feel hot and neither did the heat sink. Can I splice the harness midway to make it longer? Could I use the heat sink that is already there and mount in near one of the holes in the bumper? Is there a place that I can just order the PMD? Don't need the harness if I can lengthen, Don't need the resistor. I got a 7 and 9. Don't need the heat sink either. Did I say that this really SUCKS. I still got to drop the cash for glows and injectors as well.

there is plenty of places to get a pmd and cable just dont get a used one or a cheap one from flebay heath kennedy ss diesel places like that depends on what u want to spend i can get the grey pmd for 250

pmdcable.com.....

I bought a new extension cable and PMD from Pensacola Diesel for under $200 including shipping. I then reused my existing heat sink (which was mounted on the manifold) and resistor and mounted the new PMD in behind the bumper and kept my old PMD as a spare.

+1 Pensicola diesel, same here. The PMD is Dtech brand iirc. I also relocated my FSD cooler from the intake manifold out to the bumper right above the cooling nostril. No issues sense the move here, problem resolved

Just out of curiousity, what brand is your PMD setup? Can you take a picture for us?

It might be under warranty from the manufacturer, is why I ask (some of them have long-term warranties).

A good, clear picture will help determine that.

For the oldies here, the firewall mounting location and the short cable is an indicator...

x2 on PMDCable, never heard any problem with their cable. They also sells the new Grey Stanadyne.

For PMD only, Pensacola is fine.

You can always splice and solder it to lengthen but for under $40.

Based on the fact that you say you lost all your gages when it stalled, I'd have to lean towards ignition switch. If the PMD were failing, I would expect your oil pressure and tach to drop to zero, but your engine temp, volt gauge and speedometer should still read out.

Correct me if I'm wrong, but that's the direction I would go.

Don.

^ I noticed that Pensacola states that Stanadyne PMDs are junk and that they sell only the new improved one from Flight Systems. Would this one be any better than the gray one that Stanadyne sells? Pensacola offers the whole setup for only 269.00 which I think is good.

I cant really say that all my gauges dropped down. I know the tach did for sure. I posting pictures of the setup. Receipt says only 90 days on electrical parts. Some other wording says unlimited mileage but only 12 month warranty. The cable where it plugs into by the old PMD looks like crap.

Okay it just died on me again. Started in this morning loaded the kids and went to my parents across town. 1/4 mile maybe. Turned off truck. 2 minutes later started truck and drove off. Half way home it dies. All gauges go to zero except fuel and battery. Shifted to neutral and restarted while I was moving. Fired right up and made it home. Wouldn't a faulty PMD also cause hard starting?

Also, if this was the ignition switch, wouldn't I also be experiencing hard starting after it died? My case so far is that it fires right up.

sound like the PMD bad

^ I noticed that Pensacola states that Stanadyne PMDs are junk and that they sell only the new improved one from Flight Systems. Would this one be any better than the gray one that Stanadyne sells? Pensacola offers the whole setup for only 269.00 which I think is good.

I bought the Flight Sytems one from them - if you wanted to reuse your old heat sink you could save about $70 by just buying the extension cable and new PMD.

From looking at your pictures, I really don't like how your heat sink was installed on the firewall. With the heat sink tucked in to the insulation pad I don't see how the heat sink is getting any colling air to the fins.

^ leave it to the diesel shop who installed it to make that dumb decision. Heat sink is mounted to firewall with long sheetmetal screws. I am pretty sure it is the PMD. My wife will be the daily driver of this starting Monday as I go back to work after a long lay off. I will be ordering glows, injectors and the PMD and my 4" exhaust should be here Monday. Wasn't how I wanted to spend over 500 dollars though.

Okay this son of a b*tch will not even idle now for more than 45 seconds. This pisses me off. I cant get a PMD until Tuesday. Need to get my passport ordered and I start my job Monday. Just when I thought everything was going good. Maybe I can try the one still on the IP.

Would a bad OPS cause stalling even if you have done the OPS mod?

Update: I decided to test the lift pump again. Opened t valve and there was fuel coming out. Also the engine stumbles for a quick second. Engine then ran fine right after that. Then I opened the valve on the fuel manager. Fuel there as well. Since then engine has ran fine. Did a 40 minute drive one way that included interstate and stop and go traffic in town. Came back home and no problems either way. I am wondering if there was something stuck in the fuel system. Anyways, I changed the fuel filter out and it still is running fine. Went out on the highway and back through town. If I am lucky this was it. I still ordered the PMD kit to mount it on the front bumper. I also got glows and injectors coming too. Should be here Tuesday. Is it typical for a PMD to work then not work and then work?

yes it very typical when mine went out off on for 3 months then one day it was over

yes it very typical when mine went out off on for 3 months then one day it was over

Then I will assume that when I get the PMD bumper kit in that I will have to go ahead and install it. I was hoping that I may be able to send it back after a week or so if there are no problems. Looks like that is not the case.

yep,, just bout the time you drop it in the mail box to return, it,, you'll walk back out to the truck and it won't start! DOH!

get the new one all mounted up, pluged in and sleep good at night!

Did a 150 mile trip today that included interstate and in town driving with multiple stops. All starts the SUV just fired right up. Of course the cruise quit working for a while. In the "Information Sticky" it states the a faulty PMD may cause this as well. As much as I would like to send it back and just get my money back because it is running pretty good since the fuel filter change. But I should probably just install the new PMD when it comes in.

Just install the new PMD. It is not worth the grievance that you experience. At least you eliminate one more variable.

Also, make sure that the LP/OPS are all functioning.

^ Yeah they are functioning. I tested them as well to double check. Even used a wire from the fuse block to the G connector on the ALDL to prime the fuel manager after filter change. Exhaust, glows, injectors and PMD bumper kit all come in on Tuesday. I should have a busy weekend.

On the firewall like that has to be the dumbest place I have seen. The cooling fins are surrounded be insulation that is made to hold in heat, because all the heat goes to the back of the bay. You definately need to move that out, dont thing twice about the decision, that PMD is toast.

The grey PMD from Stanadyne would probably work just as well as the flight systems (labeled as Dtech and other), but it would be supporting those people that took 16 years to make it reliable and it uses a different connector, so would need to modify your connector and resistor.

When the checklist asks about interior lights and instruments it means did everything shut off, like no lights, no radio, no nothing like ingintion was in the off position.

If the issue persists, would be checking the LP pressure and then maybe removing fuel shutoff solenoid plunger, as it could become intermittent. It runs fine with no plunger to cut off fuel, and can easily put plunger back in.