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1999 GMC K3500 - Help!

N

ngb

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Hello everyone!

My name is Nick and I just purchased my first diesel about 3 months ago. It's a 1999 GMC K3500 with the 6.5 and 5-speed. It wasn't running when I bought it, but finally got around to putting a new PMD in about a week ago and it started right up. I drove it about 100 miles.

Probably about 50-60 of those miles were with the PMD off the pump and under the hood. When I got back home I put a heatsink on the PMD and relocated it to the front bumper. Truck ran fine for a few more days, but then Tuesday night I went to start it and all it would do is turn over. I thought it may have run out of fuel as the gauge didn't budge in the 100 miles I drove, so I went and put 2 gallons of diesel in...same story.

What does this sound like to you guys?
PMD fried again?
or crud clogging the fuel filter?
Something else?

Thanks in advance!
 
The horrors!
PMD (now FSD, btw) just can't survive without a heat sink. See the transistors? They get HOT, and thus the heatsink.
You have a great set-up now with the FSD on a heatsink out of the engine compartment and your next new FSD should last a long, long time located there.
Good Luck!
 
takes about 2 minutes for PMD to get 200+ if not on heat sink, I'd be mighty suspicious of that driver if you ran it for than many miles not on a heat sink, IIRC the one we did on test stand held up about 4 minutes before it died/started smoking
 
Schwind said:
How did you relocate it to the bumper? buy a harness (from who) or make one? the FSD will die very quickly with out the heat sink.
Click to expand...

Bought an EDAM extension of ebay and took a hunk of aluminum I had laying around, drilled 4 holes in it and bolted the PMD to it. The whole thing, heatsink and all is now directly behind the license plate, in the front bumper.

The truck was 45 minutes away from my house (at the shop) and when I got the truck running I didn't have the extension yet, so I put it on a heatsink in the engine bay until I got home. Plugged in the extension and put the PMD+heatsink behind the front bumper. Everything was great for 3or 4 more days, then I had the no-start issue.

I ordered a brand new Dtech PMD, with #9 resistor today, it should be here tomorrow morning.


Does this issue sound like it is just the PMD?
 
Turbine Doc said:
takes about 2 minutes for PMD to get 200+ if not on heat sink, I'd be mighty suspicious of that driver if you ran it for than many miles not on a heat sink, IIRC the one we did on test stand held up about 4 minutes before it died/started smoking
Click to expand...

Yup, I just unplugged the stock PMD, plugged in the new one and left if there for the drive home...

I guess I was lucky I made it home? ):h
 
I did mine that way once, winter time but I had an extension harness so I was sort of able to point it toward rad flow, and it was 40F outside, and was 20 miles from home, in a bind and had no other option,
 
Turbine Doc said:
I did mine that way once, winter time but I had an extension harness so I was sort of able to point it toward rad flow, and it was 40F outside, and was 20 miles from home, in a bind and had no other option,
Click to expand...

Almost the exact same situation, except I was probably 40 miles away. Ambient temps were just below 40F.
 
Schwind said:
I would check the harness you got from edam. his harnesses have been know to have problems. bad pins/clips.
Click to expand...

That was the first thing I checked, plugged it directly into the IP harness and nothing :(

Ordered a Dtech PMD with #9 resistor from Pensacola Diesel...+ $40 for overnight shipping
 
Got the new Dtech PMD, plugged it in...nothing! I still have to check the lift pump and try plugging the new PMD directly into the IP harness, but it doesn't look like it's the PMD...what else should I be looking at?
 
Yet another UPDATE.

Went out to do the lift pump test and when I turned the key to the on position, i heard the familiar noise that I believe to be the lift pump, so I figured I might as well see if it'd start and SURE ENOUGH IT DID!

Drove it 2 blocks home, truck started heard and idled rough for the first 5 or so seconds and there was a pretty good puff of white smoke (guess I have to replace the glow plugs as well.) Truck stumbled a little on the way home, but then idled for 10 or so minutes no problem.

Did the lift pump test, opened the valve and fuel trickled out for about 3 seconds followed by some whiteish foamy stuff for about a second then 10 seconds of diesel flowing out before I shut the valve. Truck didn't stumble or stall with the valve open. Closed the T valve and opened the bleeder on the fuel filter, got a nice spurt of diesel, so it appears that the lift pump is functioning properly.

We'll see if she starts in the morning!
 
GM Guy said:
Good luck!

Another thing i want to cover: are you running the correct oil in the NV4500? these take special oil.
Click to expand...

Not sure, any way to tell once it's in the tranny? (color, smell...) I have not replaced any of the fluids yet.
 
white foamy stuff?

ngb said:
Yet another UPDATE.

Went out to do the lift pump test and when I turned the key to the on position, i heard the familiar noise that I believe to be the lift pump, so I figured I might as well see if it'd start and SURE ENOUGH IT DID!

Drove it 2 blocks home, truck started heard and idled rough for the first 5 or so seconds and there was a pretty good puff of white smoke (guess I have to replace the glow plugs as well.) Truck stumbled a little on the way home, but then idled for 10 or so minutes no problem.

Did the lift pump test, opened the valve and fuel trickled out for about 3 seconds followed by some whiteish foamy stuff for about a second then 10 seconds of diesel flowing out before I shut the valve. Truck didn't stumble or stall with the valve open. Closed the T valve and opened the bleeder on the fuel filter, got a nice spurt of diesel, so it appears that the lift pump is functioning properly.

We'll see if she starts in the morning!
Click to expand...

You shouldn't be getting anything foamy out of the t-valve. Did you save it? What happened when it settled?
 
EDAM Harness

My EDAM harness cost me way more than a good harness by the time I was done with it. I never could keep a consistent connection with it. There are few things more exciting than driving through a rain storm while jumping in and out of the truck to wiggle the wires under the hood, just hoping it will start one more time.

I replaced that harness 8 months ago, and have never had a stall since. :mad2:
 
knh208 said:
My EDAM harness cost me way more than a good harness by the time I was done with it. I never could keep a consistent connection with it. There are few things more exciting than driving through a rain storm while jumping in and out of the truck to wiggle the wires under the hood, just hoping it will start one more time.

I replaced that harness 8 months ago, and have never had a stall since. :mad2:
Click to expand...

I have a spare OEM IP harness, so I might just make my own and swap out the EDAM one, but it seems to be working ok for now.

Rodd said:
You shouldn't be getting anything foamy out of the t-valve. Did you save it? What happened when it settled?
Click to expand...

Nope, didn't save it, after the BRIEF foamy part, i got consistant diesel out of the hose.
 
Hey for future can you update your sig so we don't have to keep going back to post #1 to see what flavor of vehicle we are talking about.

FYI since you are OBD-II (96+ yr) with key to run you can make the lift run constantly if you will jump the test plug to 12v. it is red wire black plastic female spade connector hanging out of harness by itself just below the master cylinder & underhood fuse center, as long as you have +12V applied there the lift will run, good for priming a freshly changed fuel filter, testing lift pump heatlh, and pumping last bit of fuel out if the tank if you have to drop it, remember only 15 gph so not a viable way to pump out entire tank if in a hurry.
 
Turbine Doc said:
Hey for future can you update your sig so we don't have to keep going back to post #1 to see what flavor of vehicle we are talking about.
Click to expand...

Your wish is my command!

Couple other quick questions: Is there any sort of wire pass-thru in the firewall or do I have to drill a new hole to run power back for my strobes/amps/so on...?

Fuel gauge doesn't seem to be working, goes from about 3/8 to 1/2 full. Is this common? Where should I look first?

Thanks again for all the help!
 
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