6.5TD coughing and stalling ?!?!?!?!?!?

[M123KT-450]

Yea i guess your right but this is just not how i exspected things to go i bought what appear to be a very well maintianed truck that was older with very little milage and wasn't used during the winters. . .

So inside and out the truck looked brand new engine is clean and dry, no oil and greasy sludge built up.

it's just upsetting a when you get forced into buying a truck cause you needed it like right now then 3 months later you have 5 things go bad, Very hard to smile and say Good truck !

Mike

 

[buddy]

Well, every truck has common maintenance items, youre just finding them out And unfortunately dealerships suck with this one. But there are some very competent 6.5 mechanics out there, if you can find a diesel fuel injection specialty shop, they usually know them best because of the IP failures, and some you may find rebuild our IPs and what not.

I had a dealership tell me I wasnt getting any spark and I wasnt getting any power to my injectors... I decided to tow it off their lot. Best as you have learned to just come here and learn and not only when you have a problem.

 

[JMJNet]

Some people put the PMD in front of the radiator. Inside the front grill.

PMD mounted on a heatsink with Arctic Silver is almost waterproof.

By the way, if you like statistics, most of the 6.5 out there are sold because of PMD issue caused it to stall. The stealer will diagnose them as IP and charged a lot of $$$ to change it. Most of the time, the PMD out before the IP.

You can use search and read TurbineDoc (Tim) write up about the PMD study that he did with putting PMD in different locations.

 

[JiFaire]

Relax, Mike. Take some pictures, get back to us, and we'll help you out. The good news is, your truck is easy and cheap to work on, and some fairly simple changes make it into a fuel-efficient, fairly powerful, very reliable unit that will give you years of trouble-free service.

You may well thank your lucky stars for the day you got 'forced into buying' this truck.

As others mentioned, most GM mechanics can't (and never could, really) properly diagnose these trucks, which is why they got a bad reputation, which is why they usually sell cheap. There are, however, lots of us who CAN properly diagnose these trucks, and we also know how to repair them properly.

Stick around - we'll help you out!

 

[M123KT-450]

PHOTOS

 

[JiFaire]

Hey Mike. Why are your pictures so small? Did you re-size them small before attaching them?

Anyway, you have the original FSD Cooler... the one that started the whole relocate-your-pmd craze.

Good, solid heat-sink. Crappy location. I'd almost bet your PMD is shot; it gets hotter there than it does mounted on the Injection pump, like your old one. If I recall correctly, they used crappy mounting hardware, too... the bolts that hold the PMD to the heatsink need to be stainless and have washers so you can crank them down tight - good clamping is necessary for good contact over the surface of the PMD.

The advice I gave earlier stands; you can undo the heatsink from the intake manifold and fix it up with no problems... an hour of your time, and it should be better.

BUT...

I would still strongly recommend mounting it behind the bumper. Once you have it installed back on the heat-sink, run a bead of RTV around the edge between the PMD and the Heatsink. Should waterproof it just fine. The connectors on Leroy's extension cable are weatherpak connectors, so water should not be an issue.

Heath tested one of his by starting the truck, then dropping the pmd (on the heat-sink, with the extension cable) into a 5-gallon pail of water and let he truck run like that for 1/2 hour. No issues.

Hundreds or thousands of us have ours there, and I've never heard of somebody shorting theirs out.

 

[buddy]

Ive heard of people putting it in the bumper and water damaging it, but because they didnt put the silicon bead around it. And I have seen a couple actually fail even with Heaths kit, but they give a 7 year warranty.

Yours might work fine for another year, 2 years, or maybe only a month before it totally craps out. But just doing the simple nut and bolt tightening can extend its life in most cases. At this point you could try hooking up the one still on the IP and see if it still works too, could have been pre-emptive mod with the heatsink.

I cant actually believe it gets hotter on the intake than the IP, but it does get hot, and out of the engine bay would be cooler. The D-tech PMD like I have is rated at a higher temp than my intake ever sees or the engine ever gets though, and Ive put a temp guage on it and its not gone close to its limit.

 

[M123KT-450]

so you are saying is i can use the two pmd's i have yet for a couple of months? what is the normal price?

 

[buddy]

Yeah, they will keep working, they were just getting overheated before. Sometimes your computer overheats and freezes up and restarts. At some point they will be permanently bad, really fried. You may get some life out of them with the simple things said above.

normal price is like $300 for a new one, but on ebay you can get a new D-tech type for $150-180 alone. The D-Tech type has higher temp rating.
LOOK HERE

 

[Burning oil]

Mounted ontop of the intake like his is the hottest spot in the engine bay. It will soak up the heat and run whatever temps are coming off the radiator & fan. The heat sink has nowhere to dump anymore heat once the surroundings are as hot as the sink its self.
Mounted to the IP the cooler fuel pumping though it will absorb some heat. I always saw it will run about 10-20* cooler on the IP than inside the engine bay on a heat sink.

 

[Bullseye240]

Almost sounds like air in the fuel lines to me. Might as well get under the truck and check the connections at the lift pump and make sure that both are tight. Mine were loose when i replaced my old pump with the FRB-5 and it would hicup and sometimes die. Just my .02 as its a free fix to tighten the lines.

 

[bison]

Mounted ontop of the intake like his is the hottest spot in the engine bay. It will soak up the heat and run whatever temps are coming off the radiator & fan. The heat sink has nowhere to dump anymore heat once the surroundings are as hot as the sink its self.
Mounted to the IP the cooler fuel pumping though it will absorb some heat. I always saw it will run about 10-20* cooler on the IP than inside the engine bay on a heat sink.

I agree, but it also depends on where you live.
i got mine still on the 95's intake as well, but in my area this winter the temps of the FSD and cooler where never warmer than 20c, the pump ran at 30c.
I still fried 2 PMD's in the last 3 months,the 3rd one just gave a couple of hickups in the last few day's.You go figure.

If heat kills PMD's, then what in the world killed mine,running at room temp only?

 

[NVW]

I agree, but it also depends on where you live.
i got mine still on the 95's intake as well, but in my area this winter the temps of the FSD and cooler where never warmer than 20c, the pump ran at 30c.
I still fried 2 PMD's in the last 3 months,the 3rd one just gave a couple of hickups in the last few day's.You go figure.

If heat kills PMD's, then what in the world killed mine,running at room temp only?

Bison, do you monitor them with a temp gauge? I had mine on the intake from Jan.- May of 2007 and it fried. I think it was heat soak that did it in, I was also using a winter front in the coldest weather.

Leo​

 

[buddy]

Mounted ontop of the intake like his is the hottest spot in the engine bay. It will soak up the heat and run whatever temps are coming off the radiator & fan. The heat sink has nowhere to dump anymore heat once the surroundings are as hot as the sink its self.
Mounted to the IP the cooler fuel pumping though it will absorb some heat. I always saw it will run about 10-20* cooler on the IP than inside the engine bay on a heat sink.

I guess that completely depends how hot your truck gets then. The configuration of the truck, how much fuel you flow, the ambient air temp, the tasks you do with the truck, etc....

So on the intake is not the best place, but doesnt mean it frys everyone's because my engine never gets over 185* and when I monitored the heatsink it never even got that high, and I never couldnt put my hand on it, if using the stanadyne PMD I can see it being bad because its only rated to 195*, but the D-tech is rated to 225*. With an S engine, with lower fuel flow is probably worse off then a modified F engine program pushing 85mm3 of fuel.

Burning Oil, do you even have a PMD?

 

[Burning oil]

Im only letting you know that no matter what you do when mounting the PMD ontop of the intake is the hottest spot in the engine bay. On a cold day it may never get up to a hot enough temp to hurt anything, BUT in that location it is still the hottest place on any given day. Whatever temps are coming off the radiator is what the PMD will see or slightly higher.
I do not say this out of my opinion, but from testing.

 

[bison]

Bison, do you monitor them with a temp gauge? I had mine on the intake from Jan.- May of 2007 and it fried. I think it was heat soak that did it in, I was also using a winter front in the coldest weather.

Leo​

I use a infrared thermometer to monitor the temp right after at least a 50k trip, ever since the first PMD fried. most times the cooler reads 16 to 25 c PMD 2 degree hotter. ambient temp 0 to -30c no winter front. original IP mounting spot around 30c. top of intake cover 5 to 10c. coolant temp right where it should be.

 

[JMJNet]

IIRC, the Stanadyne PMD only designed to withstand somewhere up to 85C (185F). Normal engine temperature is around 200F to 210F hence the ambient is higher than that. When engine shutdown, ambient is usually go up by 10F to 20F with no air movement. When engine shutdown, the heatsink is supposed to be able to shed the heat fast but actually absorb the heat. So that is the time when it is fried. Ambient has to be lower than the heat that PMD generates in order to shed the heat. When Ambient is higher, it will ruin electronic. Why is our PC CPU have a heatsink and fan?

The DTech PMD is spec'd at 125C (257F).

You judge it yourself.

 

[jmiller]

I just got done with a bout of stalling with my truck.

After replacing the fuel pump, it started to buck and wanted to stall.

I check the filter and found air in it. Bled the air and went down the road. Later, it actually stalled this time. Checked and found air in the filter again.


Thinking I pinched the o ring, I slid under the truck to replace it. Only to find the fuel line rusted and wet with fuel near the tank.

Replaced the line, bleed the air, runs like a charm and no more air in the filter after driving down the road.

BTW, My PMD has been on the intake for 2 years I've owned it and probably a few years before I got it. Rough running or stalling isn't always the PMD. Look at the simple things first.

Yes, the first time it started to buck, I thought the PMD had given up the ghost. Until I checked the easy things, like bleed the fuel filter.

 

[Turbine Doc]

It may not be too bad then. Pull that heatsink off the intake, find the right torx or allen driver and tighten the screws that hold the black box/PMD on. Only required on SSD crappy set up that requires underhood installationOr even better would be to take it off and apply new thermal grease and tighten the screws as much as you can. See if the PMD/FSD has Standadyne on it anywhere. If you remove the PMD/FSD then you can go as far as tightening the nuts that hold the two 500W transistors down. Sure fire way to break one overtorque the studs on the nuts and you will be replacing it

Its a Pump Mounted Driver (PMD) but when not on the pump people call it the Fuel Solenoid Driver (FSD) since its not on the pump.

Also, make sure that ground wire on the side of the heatsink is tight, Again another of SSD's dumb ideas that has you remove the factory gnd for the fuel solenoid to the heat sinkbut you really want to add a wire from the side of the heatsink back to the bolt on top of the IP or even down to the engine ground below the heatsink. This grounding may be your only problem. Clean the ring lug on the IP but leave it there

According to the people that make those heatsink kits you need to tighten the bolts every 3k miles. And according to everyone on this site you need to get it away from the intake. You can by a cable that is long enough to put it in the bumper where it will be cooler, but youd have to weatherize the PMD/FSD. PMDCABLE.com

If you have a stanadyne PMD/FSD then there are aftermarket PMDs (i.e. D-tech) that are better (higher heat rated components) for like $180 on ebay, or you can find used tested ones for like $30 there. Its good to have a spare becuase it could leave you stranded no matter what kind it is or where you put it.

Your problem will only get worse if you dont do anything. Try tweaking the bolts and adding the ground wire at a minimum.

He's described a DSG cooler that does not require a gnd, it leaves it where it is supposed to be, think about it it's grounded to the intake trough the intake bolts, the driver gets it's gnd through the harness/IP lug, unless remover per SSD's instructions.

Buddy do us all a favor, leave the SSD crap at the SSD site, had SSD done a better job of copying the Beta/DSG/Kennedy coooler maybe theirs would not have as many failures as it does.

ANY COOLER UNDER HOOD IS BAD JU-JU DO NOT MOUNT IT THERE REGARDLESS OF VENDOR YOU BUY FROM

Best kit bar none is the Heath, 2nd best is a Beta/DSG/Kennedy remoted out of engine bay on a PMD.com extension harness, you could do a DIY harness, but simplicity dictates the Heath or PMD.com

 

[Turbine Doc]

I guess that completely depends how hot your truck gets then. The configuration of the truck, how much fuel you flow, the ambient air temp, the tasks you do with the truck, etc....

So on the intake is not the best place, but doesnt mean it frys everyone's because my engine never gets over 185* and when I monitored the heatsink it never even got that high, and I never couldnt put my hand on it, if using the stanadyne PMD I can see it being bad because its only rated to 195*, but the D-tech is rated to 225*. With an S engine, with lower fuel flow is probably worse off then a modified F engine program pushing 85mm3 of fuel.

Burning Oil, do you even have a PMD?

Ever check it post shutdown, heat soak is cumulative damage done