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AKA Moses Lawnagan
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Discussion Starter #1
I've got a '99 GMC 3500 4x4 crew dually with the 6.5TD, and about 148,000 mostly trouble-free miles. Over the last 5-6 months, I've had maybe three instances of the engine stalling while driving down the road, just like somebody reached over and turned the key; then the engine would catch and start running again in a couple of seconds. I'm thinking the injector pump, or hopefully the PSD (pump solenoid driver), which is the "brain" for the pump, was getting ready to bite the big one.

Well, today, on the way to work, it did. Engine stalled, and wouldn't restart immediately. I rolled off the road, sat for 5-10 minutes, and tried to restart. It did, but only ran a few seconds, and quit. 5 minutes after that, I tried again, and it started and ran long enough to move the truck to a safer place off the road. I called AAA, and when the big roll-back arrived, the guy started my truck and drove it onto the roll-back, and it sat and idled for the time it took to tie it down to the bed. I'm beginning to think that it IS the PSD and not the pump.

Drop it at the local GM dealer, mainly because it was fairly close and I didn't know where else to take it yet. He calls me later in the day and says I need , you guessed it, the entire injector pump and PSD assembly ($875) and with related gaskets and other incidentals (you have to pull the intake manifold), and labor, it would cost me $1907. Ouch.

When I asked how he knew it wasn't just the PSD, he said that the mechanic was "real good with these diesels, everybody brought theirs here", but when I asked what codes were brought up on the OBD II diagnostic, he said "the guy goes by how it sounds, he's been doing this a long time". (according to two different websites I read, there are specific codes that will distinguish PSD from pump failure)

HOW IT SOUNDS?? It starts and runs, is how it sounds, although it then quits after an while, or not. If the PSD is bad, it can do the same thing but the pump has to operate to pressurize the fuel rails to the injectors. If the pump is bad, it won't do that at all. Not to say it isn't going bad, but he's not willing to replace the PSD first (which can be done without removing anything, just unplug the one on the pump and plug in a remote). If that doesn't work, then I know I have to do it all. He wants all or none. I can get out for $350 if I just replace the PSD.

What to do, what to do..... The truck is at the dealer, I'll have to get it towed to somewhere else, gotta check on local diesel specialists, who then have to do their own diagnostic, ......

Everything I've read tonite on several different diesel sites on diagnosing this problem, from the symptoms my truck has, indicates that it is 85% chance it's just the PSD gone bad. The OEM PSD is mounted directly to the pump; there is a history of the PSD failing due to heat soak on all 6.5TD's from '94 to 2000 model. So much so that several aftermarket companies have come out with replacements which mount elsewhere and have large heatsinks mounted to them to keep them cooler.

Long story, sorry. It puts a big stop on my "lawn care" sideline, as I don't have a way to haul my tractor until it gets repaired.
 

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they can be a pain in the arise thats for sure i was a mechanic for 15 years and i had a 6.2 in my 86 1 ton crew cab dully ..I went on vac took the camper trailer off i went ..working great got 200 miles away from home in the middle of know where and poof pig wouldn't go ..did the same thing you did had it towed in ..Got the same BS i was told its your injector pump its going to cost you 800 for a used pump and some god awful price for a new one and all that BS..I said no i dont think so ..I think its the fuel pump myself or the filter in the water separator is gone ...They asked how i knew this i said i read alot lol just change the fuel pump ...guess what they changed the pump and boom it fired right up ..then i handed them my bizz card and said thanks lol...They should do what you ask no ifs and or butts not all mechanics are right i have been wrong myself a few times
 

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The Magnificent
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20,952 Posts
Isn't the pump a knee jerk reaction?

Your dilemna is of course you only get one tow with your insurance. So, you are out another tow charge for the second opinion.

If the PSD is the culprit, can you not save a bunch by changing it yourself?

As far as diagnostic codes, I bought a code scanner for my VW, which has already paid for itself many times over.
 

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The pump is most likely OK. They should be able to check pressure to verify if pump is bad. While the pump is at 148,000 miles, I've seen some pumps run 200,000+ miles without replacment. It all depends on the owners ability to change the fuel filter on a regular basis, keep water from going to the pump, and add a little conditioner every so often.

Ask them to pull the codes, and if it is the PSD, replace the PSD. Get "the kit with the finned housing" to relocate it to a cooler spot. Replace fuel filter, and you should be good to go.

They shoudl be able to do some diagnosis rather then just throw parts at it.
 

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somanytractorsolittletime
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493 Posts
I have a 2000 gmc van with a 6.5 diesel, I have had the same thing happen to me. I will tell you somthing about the dealer, they will replace the pump and pmd because they can't test them. It's easier for them to replace the whole unit. Do not buy a GM/stanadyne pmd for your truck. Buy a Dorman it is a better unit. Also don't mount it back on the side of the injection pump. Mount it on the back of the front bumper with a large heat sink it will last forever that way. I did this with my van and have never had a problem again. You should be able to get to the plug on the pmd and take it off. Buy the extension harness on any of the diesel sites that sell them (or do what I did make your own harness) get the harness long enough to put the pmd on the bumper with a heat sink be sure to use heat transfer paste or the gasket. this will be alot cheaper than having the dealer do it. You can leave the old pmd right on the pump, mine has been on for 3 years.The main thing is to keep the new one off the pump they overheat and burnout. Stanadyne told GM about this problem and tryed to convince the enginners at gm to have a heavier duty version or mount it off the pump, I have talked to the one of the stanadyne/gm pmd designers and they told me about the problem years ago,It was all about money! thats why gm put a 7 year 100,000 mile warranty on the pump/pmd, for a while they were failing like crazy so gm dealers were just replacing the whole pump instead of just the pmd. Feel free to ask me any questions if you would like. I have worked on the 6.2/6.5 diesels for years, rebuilt quite a few so I have some experience with them.

Pat
 

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Make a deal with the stealership. Have them replace pmd first if that dont fix it then they can replace the pump assy.

Another thing I like to do is go and talk face to face with the mechanic, bypass the service writer.

And obviously the guy is good with this repair, when you replace all the components its hard to be bad.

Good luck, The only place I know of is the big truck repair center on the east side of town on I40/85. They have done warranty work on our firetrucks.
 

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MTF Member Since Day 1
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623 Posts
Some good information, I'd purchase the PSD and change it myself in the dealership parking lot,drive off when it starts, go home and re-route the placement to a better location and be done with it.
 

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Owner of The Bandit #55
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34 Posts
Changing filters and fluids plays a big roll in truck life. My dad has a 2002 chevy dually with the duramax 6.6 L. He bought it used in like 04 when it had 30,000 miles on it. Now it has 210,000 miles on it and is still on factory everything. Even injectors. The only thing he replaced was some power steering hoses because they were chewed by a dog and was full of leaks. I think its BS that they even think about doing something just because of "the way it sounds". They need to run tests on the thing. Just my 2 cents take it for what its worth. Just remember to change those filters and fluids when its time. Thats how my brother trashed the tranny of his 03 duramax he fixed up.
 

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The pump will not likely be at fault. I have worked on several different diesels and the pump rarely stops you dead. and if it did, cool down time wouldn't help. I'd go with the module.
 

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AKA Moses Lawnagan
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4,643 Posts
Discussion Starter #10
Seems like you guys and I are all on the same page.....while the dealer is reading a different book.

I understand from their perspective. They (GM and dealers) treat the injection pump and PMD as a single unit, so if one part is bad, replace the whole thing. The history on this pump and driver is clear. '94 and '95 models had such a problem with them that GM extended the warranty on the pump and driver to 110,000 miles for all subsequent models. Mine being a '99, they had refined the system by then and had fewer failures, but they didn't change the base design, which is the problem in the first place. I've had this truck since it had 20K miles, and have been well aware of this from reading the diesel truck forums over the years I've had this truck. Almost to a man, the recommendation is to move the PMD away from the pump itself, as it is in an area that gets little air circulation and tends to heat-soak from the heat from the pump. (oddly enough, the original design from Stanadyne counted on "cool" fuel flow to the pump to keep the heat down). Maybe I should have been a bit more pre-emptive and done this 40K miles ago.

The fuel filter gets changed every time the oil/oil filter gets changed (3000-3500 miles) and I always add Diesel Service conditioner to each tank of fuel. I had to have the lift pump replaced about 25,000 miles ago, and it still works fine, you can hear it when you turn the switch at start-up.

I ordered the remote PMD (also called an FSD, depends on whether you use GM or Stanadyne terminology) from Accurate Diesel.com. It comes as a kit with the large heatsink and resistor and is "plug and play". I'll plug it in at the dealer, and should be able to drive away. If, on the other hand, the pump IS bad, I can order the pump separately (also from Accurate) for much less than GM wants. It is a re-man, but all the wear items are completely new, especially the optical sensor, which is the most often failed part in the pump itself. It comes with a year warranty. I went by the dealer where my truck is, they stand by their "diagnosis", but are willing to do it my way (after all, it IS my truck)

Then my decision is whether or not I should have the local dealer install it. On the one hand, the truck is already there, and would I spend more or less to have the truck towed somewhere else that MIGHT do it cheaper. Come about Tuesday, when the new part arrives, hopefully it is a decision I won't have to make. I'm not driving this truck much now, I bought another vehicle as a daily driver, but having the truck reliable enough that I'm not stranded with my tractor and trailer behind it is important.
 

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My dads 6.5 just blew up on him outside Des Moines. Second engine, doesn't even have 30k on it. He was just pulling an empty trailer on the highway, said it just blew apart on him. Last engine broke the crank, on the highway empty.

That truck has been nothing but a POS (4 starters, 2 transmissions, 2 engines, injection pump, diff is worn out). It's a 95 Chevy 2500. I really hope he gets something else this time, if that engine didn't have a warranty we're going to be out several thousand.
 

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somanytractorsolittletime
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493 Posts
Yes sir,the blocks on the 6.5 had a bad casting which caused the main bearing saddles to crack /shift. then the crank would go then rods. I had 3 rods on my wood stove from a 2000 6.5 that exploded 2 rods were twisted right around. Gm called it acceptable loss. The engine I have now has a aftermarket block which is much heaver than the GM block and is a high nickle casting.
 

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Yes sir,the blocks on the 6.5 had a bad casting which caused the main bearing saddles to crack /shift. then the crank would go then rods. I had 3 rods on my wood stove from a 2000 6.5 that exploded 2 rods were twisted right around. Gm called it acceptable loss. The engine I have now has a aftermarket block which is much heaver than the GM block and is a high nickle casting.
On the original engine they said one of the heads had a crack in it possibly filling up one of the cylinders with coolant causing it to hydrolock. I'm not 100% sure what really happened though.

He rented a U-haul and is hauling his truck and the trailer to his destination. A Cummins 12v swap maybe? It'll be interesting to see what really happened to the engine, he just said there was lots of oil and smoke. :banghead3
 

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The cranks were a weak spot on the 6.2's too,usually they crack after the harmonic balancer slips on its rubber mounting,sometimes for no good reason at all....I have one with a busted crank that came from a 1 ton ramp truck that a friend owned--it was just running at idle one day while loading a car up and the engine started hammering,and it soon seized..I grabbed it for parts before he scrapped it,it still has a like new injector pump,the "J" code intake with no EGR,and the injector lines might be useable,nice exhaust manifolds..--ones on my two trucks are getting quite crispy..this engine had only 50K on it too,good heads,etc..I could probably put a crank on it and it would run good again I bet..

Many 6.2 and 6.5's break off starter bolts and noses because no one ever puts the little brace on the motor end to the block on them--its a must on a diesel,gas engines were supposed to have one too but dont often..the high compression of the diesel really puts the bolts under a huge stress and sometimes the engine block even cracks at the outer bolt hole...

The overdrive automatics in GM's weren't the best they ever had,the 480LE is considered their best so far,but I prefer the good old TH400 ,the Aloson is a nice tranny--or a manual tranny,preferably a 5 speed for towing..
 

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somanytractorsolittletime
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The early 6.2 blocks were considered "good" high nickel blocks,the bean counters at GM had not got to that far yet. But they did later.I had a 86 gm van with a 84 block/crank 85 big valve heads,the rods and crank were magnafluxed rods resized and new bushes in the small end done,and the rotating assembly was balanced by L&L Machine, I had the heads square thread plugged and welded between the valves, 18 to 1 low compression pistons instead of 21 to 1 with a banks turbo it was a good engine.I had Gomers diesel set me up a 6.5 mechanical injection pump for it. That engine never gave me any problems.
 

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Seems like you guys and I are all on the same page.....while the dealer is reading a different book.

I understand from their perspective. They (GM and dealers) treat the injection pump and PMD as a single unit, so if one part is bad, replace the whole thing. The history on this pump and driver is clear. '94 and '95 models had such a problem with them that GM extended the warranty on the pump and driver to 110,000 miles for all subsequent models. Mine being a '99, they had refined the system by then and had fewer failures, but they didn't change the base design, which is the problem in the first place. I've had this truck since it had 20K miles, and have been well aware of this from reading the diesel truck forums over the years I've had this truck. Almost to a man, the recommendation is to move the PMD away from the pump itself, as it is in an area that gets little air circulation and tends to heat-soak from the heat from the pump. (oddly enough, the original design from Stanadyne counted on "cool" fuel flow to the pump to keep the heat down). Maybe I should have been a bit more pre-emptive and done this 40K miles ago.

The fuel filter gets changed every time the oil/oil filter gets changed (3000-3500 miles) and I always add Diesel Service conditioner to each tank of fuel. I had to have the lift pump replaced about 25,000 miles ago, and it still works fine, you can hear it when you turn the switch at start-up.

I ordered the remote PMD (also called an FSD, depends on whether you use GM or Stanadyne terminology) from Accurate Diesel.com. It comes as a kit with the large heatsink and resistor and is "plug and play". I'll plug it in at the dealer, and should be able to drive away. If, on the other hand, the pump IS bad, I can order the pump separately (also from Accurate) for much less than GM wants. It is a re-man, but all the wear items are completely new, especially the optical sensor, which is the most often failed part in the pump itself. It comes with a year warranty. I went by the dealer where my truck is, they stand by their "diagnosis", but are willing to do it my way (after all, it IS my truck)

Then my decision is whether or not I should have the local dealer install it. On the one hand, the truck is already there, and would I spend more or less to have the truck towed somewhere else that MIGHT do it cheaper. Come about Tuesday, when the new part arrives, hopefully it is a decision I won't have to make. I'm not driving this truck much now, I bought another vehicle as a daily driver, but having the truck reliable enough that I'm not stranded with my tractor and trailer behind it is important.
I had the same problem with my 98 C2500. I ordered a new PMD from Pensacola Diesel with the remote heat sink and mounted it behind the grill. I got a D-Tech, it takes more heat than the Stanadyne. Cost less too. Check out www.dieselplace.com for more info on your 6.5 TD. It's helped me alot.

The faulty part of GM's engineering was that the fuel keeps the PMD cool while the engine is running, but on shut down it's in the hottest part of the engine valley. Let us know how it turns out.
 

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I think GM used the "good" alloy in the '82 engines to help ensure they didn't have a repeat of failures,their reputation suffered greatly after the engineering disaster thier Oldsmobile gas 350 based diesels that turned out to be turds and self-destructed in less than 30K miles in many instances....the 6'2 wasn't thir best diesel but its not the worst either,the 5.7 Olds one holds the crown for that title!..

My boss had a '78 Caddy Seville with a 5.7 diesel and a TH200 tranny..now THAT was a fine peice of automotive engineering!:rolleyes: ..the local chevrolet dealer owed his parts store a few grand,and they decided to trade the caddy for the amount due..they got it in trade with only 25K on it..he loved the car,it got as much as 27 mpg..but it had a lot of problems too!..the engine held up though,probably because he was anal about using the right oil and changing it often,and he drove like grandpa!..
 

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I had a '79 Olds wagon with the 5.7, at 4300 miles it pulled the wrist pin out of a piston while it was idling, just stopped with a bang. The dealer replaced the short block, re-used the heads, and all was well. I think they simply could have put a piston in it and put it back together. Not wanting something that could suffer a catastrophic failure like this, I quickly sold it before their reputation really got out, got about ninety cents on the dollar. The person who bought it ran it over 100K miles without incident. I once saw the inside of a new shortblock, it was the sloppiest POS I ever saw. If you dragged your bare hand over the crankshaft and rods, you'ld be on your way to the ER to get put back together from all the burrs in the engine.
 

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AKA Moses Lawnagan
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4,643 Posts
Discussion Starter #20 (Edited)
The 6.5 engine has its faults, but is basically a good light duty diesel. It does more than light duty in several of its applications, since AM General has used it in the military HumVees for many years with good success and service. And the 4L80E tranny is a good one, I have 150,000 miles on mine and have had no issues whatsoever, I've had the fluid changed three times and that's it. I pull a 6000 lb gooseneck horse trailer occasionally, and a flatbed with my tractor several times a week. The D-Max and Allison is a light-years jump above them, though.

I got the remote PMD with heatsink on Monday. The guy even sent me an extension for the harness, which normally cost extra, but he didn't charge for it.

I went straightaway to the local GM dealer where I had the truck towed, and had it installed in twenty minutes. The hardest part of the install was getting a long pair of needlenose pliers down to the wiring connector on the PMD through a hole about the size of a quarter (it's under the intake manifold and in the corner that the A/C compressor sits directly above the manifold). I got it off the old PMD and fished the wiring connector out the hole, plugged in the new PMD, and mounted it to the top of the intake tube (the recommended spot, as it is in the airflow from the fan).

The mechanic who had checked out the truck and recommended a new Injector pump came out when he saw me hanging over the front of the truck in the front parking lot, and wanted to know what I was doing. I had cleared it with the service manager, so I told him I was trying something other than what he said was wrong. he told me he'd seen hundreds of these injector pump problems and the only real fix was replacing the whole pump assembly. My response to him was that I could understand that from GM's perspective, as they don't sell the PMD as a separate assembly and the only way they can replace it is to do the whole pump and driver. I suggested that he read just one or two of the on-line diesel sites and their take on the long-time problem that GM has had, and what these diesel specialists have concluded is the real problem. I figured it would do no harm at all to see if a $350 PMD would fix it before paying $2000 for a new pump and installation labor.

He said, "do what you want, it isn't going to fix it", which was about the time I had plugged the new one in. So I went and turned the key, it fired right up. I've put about 250 miles on the truck this week without so much as a hiccup, and I've been pulling a flatbed the whole time either with my tractor on it, or a couple of loads of old lumber that I took to the dump.

I told the mechanic, while I was sitting there holding the truck at a constant 2000 rpm, that there was probably a big pile of perfectly good injector pumps with bad PMD's in their old parts dumpster. I just wish the owners of all those replaced pumps could know how they've been ripped off by GM because they don't make the PMD available separately.
 
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