http://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gif
this am my truck started stalling.PMD i figure.
i am driving home with no pblms at all,drove at least 20mls.I floor it to pass a car and the engine stopsi slow down to restart and the starter grinds because it is already started???i floor it again,once it gets to about 65mph the engine stops,let my foot off the gas once it slows down the engine starts again.did this 4 times.I start driving normal and it stalls 2 more times,i stoped off at pepboys for gas treatment and then drive home(5mls) with pblms at all....
I did notice over the past 1-2days that it didnt have the normal power when giving it gas.friday the check engine light came on once for about 5seconds then went out and has not been on since.any ideas???I am going to pull the pmd and make sure the bols are tight as suggested by other members in my last post,and make sure the pmd has a good ground.http://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gifhttp://www.dieselplace.com/forum/images/smilies/censored.gif

Good fuel filter?
Lift pump working?
Sounds like the engine is starving for fuel at high rpm's. It guzzels that dinosoaur gravy when you plant the tach up in the upper numbers. Although the PMD is the downfall of the fuel system, you don't want to blame it every time something happens to the truck. Sounds like if it were a PMD problem, it would out right die, rather than still be running.

what part of fort worth are you in?

answering grapes question--im in north fort worth of Beach and Basswood.( near watuga)

here is what i found so far...when i pulled the pmd the four allen screws were about finger tight,when i pulled the pmd off the cooler i found that all four nuts for the resistors were about the same just barely finger tight...how tight should these be???

also in response to knkreb--i sya pmd because of the way it was stalling this morning.I could start it up it would run about 5-10 seconds then die did this about 20 times while trying to drive across the street at work.It didnt do the stalling at high rpms untill today that i noticed....i can put the truck in drive and turn the key on and hear the humming fro the pump,I can open the wter tee while it is running and it doesnt die...any thoughts

Open the bleeder on top of the filter instead. If you have a plugged filter, it will still flow ok out of the water drain but not out of the bleeder.

opened up the bleeder on the filter-squirted out diesel...

put the pmd back on and truck would not start at all..the only thing i changed was move the ground wire from the original location on the pump to the cooler itself.....removed ground from cooler and spliced in a longer wire and ran to the batt.truck now starts and is idleing in my driveway...im going to change out the headlights on the wifes jeep and let it idle for a while before doing a test drive just to make sure it has time to heat up...

could the tightness of the pmd bolts and resistor nuts have anything to do with my issue???could the ground have anything to do with it???

i'll post up in about an hr with any results...
http://www.dieselplace.com/forum/images/smilies/redface.gifhttp://www.dieselplace.com/forum/images/smilies/redface.gifhttp://www.dieselplace.com/forum/images/smilies/redface.gif

well i let it idle for alost 30min then took it out and drove it hard.I went to a long empty road and got it up to 85 before taking my foot off the gas.The power that was not there before is there now.I did this run about 4 times and it only died once but then started right back up as soon as the speed went back below 60...
the pump is working because when i open the bleed screw on the filter it pours out,but i will say that the humming noise that i hear from the pump is kind of a slow pumping hum,if that makes any since.

My PMD is out in the air filter box, with no ground attached to it. It looks like a little metal porcupine sitin' in there. Transistor nuts, yepper, dat be de problem looks like. Time will tell after some drivin' to make sure that was only it, or if maybe it's cooked inside?

I don't understand what you mean, you say the truck 'dies' under load, but when you slow down it starts back up. Are you just getting kicked into limp mode and getting your fuel cutback or is it actually stalling? Hard to say for sure, but you may need a Wastegate actuator solenoid. Can you tell us what codes are stored on there?

I don't understand what you mean, you say the truck 'dies' under load, but when you slow down it starts back up. Are you just getting kicked into limp mode and getting your fuel cutback or is it actually stalling? Hard to say for sure, but you may need a Wastegate actuator solenoid. Can you tell us what codes are stored on there?

this morning it was stalling completly while just running at or just above idle.i could barley move the truck 20ft without it stalling completly and having to restart...What i was talking about when it was dying and then restarting while under load was today after work driving home i had no stalling issues but when i went to pass a car doing about 60 it just "shut down" i noticed at around 50 the enigne would be running again.i floored it a couple of more times and each time it did it.then it started having stalling issues...the best way to describe it is like if you have chevy gasser and floor it,once you are doing about 100 the engine will shut off till you get below 90 then it will start again..that is the best way to describe what it was doing.

but like i said in my post above all of the allen bolts holding the pmd tothe cooler and the nuts on the resistors themselves were all less than finger tight.once i tighten them up and moved the ground from the pmd straight to the batt, it seemed to have full power back and i got it up to 90 twice before backing off the throttle.
The wastegate solonoid is new as is the pump.its getting plenty of vacum and boost.you can hear my turbo whining even at idle and under throttle it is real loud,almost like a cummins.Let off the gas and you can hear it winding down very pronounced.

High rpm fuel issues could also be fuel filter or lift pump.

if iti was starving for fuel at high rpms due to filter or lift pump,wouldnt it kinda sputter??This just shuts down,like just turning the key off then turning it back on after it gets below a certin speed.

How much did you tighten the transistor nuts on the pmd? To quote someone else on here, they should be "finger tight, then a 1/4 turn more." (Turbine Doc said that, I think).

How much did you tighten the transistor nuts on the pmd? To quote someone else on here, they should be "finger tight, then a 1/4 turn more." (Turbine Doc said that, I think).
tighter than that i think....the 4 allen screws that hold it to the heat sink were also real loose..it seems to have helped.its not stalling now.It still has the issue when im driving 65mph+ where the engine will just die untill i get below 65 then it will run again..It happend this morning driving to work.I was doing about 75 and the engine quit i let off the gas and let it bleed the speed off by coasting.I watched the tach the whole time and around 60mph the tach jumped back up to around 1500rpms and ran fine the reat of the way to work.almost like it has a speed gov set to 70mph...
Any thoughts????
Filter was changed last month around 3000 miles ago...

Check, double-check, and triple-check the battery connections. Loose/bad/dirty battery connections can throw the truck into limp mode.

I am not sure the turbo whine should be that loud on a 6.5TD, but anyhow getting back to your original problem. I certainly sound like the PMD to me. Replace it with remote kit, and get it in front of the radiator and out of the engine compartment altogether.

Codes? Paper clip trick to read em.

I am not sure the turbo whine should be that loud on a 6.5TD, but anyhow getting back to your original problem. I certainly sound like the PMD to me. Replace it with remote kit, and get it in front of the radiator and out of the engine compartment altogether.
the turbo whine is very pronounced due the air cleaner.I am using a 180 degree bent tube to point the cone filter away from the airwash of the fan and away from the water spray from under neath the truck...I have my pmd mounted to a heatsink that is mounted to the two intake bolts on the drivers side.Also i didnt use the heat transfer pad,but instead used the white paste that came with it.If i end up buying a new one i will use the pad this time...

I forgot to mention...when i replaced my pmd last summer i removed the two black covers that were covering the resistors on the back of the pmd.Should i have left them on or was i right to remove them???

Okay, really wild thought here. . . check the braided ground going to the passenger side head to the fire wall. Critical ground for ECM. Maybe we're barkin' up the wrong tree here, but in the right forest.

The high speed cutout maybe your ECM is seeing either too much boost, or too high intake air temp and cutting fuel out. If you engine is still running, it's still getting fuel, just at a reduced rate to continue to run.

Any takers on those theories?

The ground wire you removed from the Inj Pump is the Fuel Solenoid dc return - shorten it to original length, re-attach to the IP for correct current supply to the Solenoid.

FSD\PMD has two grounds - one from that source for high-current drive, other sourced from PCM for signal drive.
Don't cross-ground them.

Possibility FSD may have sustained damage from improper grounding procedure - try another AFTER servicing wiring harness connections\grounds.

Black plastic covers may be removed from module transistors - they are electrical insulator\ heat deflectors.

Clean all electrical connections - PCM harness-to-engine grounds, battery, harness connectors, etc. - your failure description sounds like electrical.

Could also be ingition switch - has several separate circuits.
PCM\Ignition is high current circuit - fails, leaving instrument panel and accessory circuits functional, confusing troubleshooter(s).

Could also be Engine Shutoff Solenoid, top front on IP - easily replaceable - could be heat failure.

Could also be the IP fuel strainer\filter is dirty - worth a look while solenoid is out - remove the fuel inlet fitting.

Could also be IAT sensor failure, but that would give SES\MIL and DTC - does your SES indicator illuminate at key-on?

the ses light does come on when you first turn the key then goes out as normal...
as far as the ground to the ip pump,I have seen several members pics that have theres grounded to the heatsink on which the pmd is mounted.i would think as long as it was going to a ground somewhere it shouldnt matter,since the ip pump itself is also grounded.It was only moved over about 5inches to where my batt ground connects to the block.

someone had mentioned the ingnition before...is it hard to replace,anybody knwo the cost?and do i have to use a new key or does it use the existing tumbler??

well its still stalling.
drove it for 30min yesterday and it stalled in the street.would not restart for anything.sat there for over an hour and t still would not start.called a tow truck waited for another hour for them to tow me home,still wouldnt start.let the truck sit for 5 hours then it started....its getting fuel.If i oen the bleed valve on the filter and turn the key ,fuel pours everywhere...the filter is new.

With it dead, did it smoke when you tried to start it? Wondering if fuel is making it to the injectors?

Have you plugged a different driver in yet?

QM, can you see what the speed sensor is actually reading?

I've had a faulty speed sensor on a Pontiac Firebird ('91 V6) once, together with a wrecked PCM, probably due to ignition wires leaking out current. Sypmthom was a stalling engine, sometimes dying and hard to start, very much like you describe.

Speed sensor was reading 255 mph or so, probably the PCM stalled the engine on purpose ...

With it dead, did it smoke when you tried to start it? Wondering if fuel is making it to the injectors?

didnt smoke at all...

QM, can you see what the speed sensor is actually reading?

I've had a faulty speed sensor on a Pontiac Firebird ('91 V6) once, together with a wrecked PCM, probably due to ignition wires leaking out current. Sypmthom was a stalling engine, sometimes dying and hard to start, very much like you describe.

Speed sensor was reading 255 mph or so, probably the PCM stalled the engine on purpose ...
possible.it was stalling the last couple of days when i would go over 70 then start back up on its on when the speed dropped below 60.....
How much is a new pcm????

The ground wire you removed from the Inj Pump is the Fuel Solenoid dc return - shorten it to original length, re-attach to the IP for correct current supply to the Solenoid.

FSD\PMD has two grounds - one from that source for high-current drive, other sourced from PCM for signal drive.
Don't cross-ground them.

Possibility FSD may have sustained damage from improper grounding procedure - try another AFTER servicing wiring harness connections\grounds.

Black plastic covers may be removed from module transistors - they are electrical insulator\ heat deflectors.

Clean all electrical connections - PCM harness-to-engine grounds, battery, harness connectors, etc. - your failure description sounds like electrical.

Could also be ingition switch - has several separate circuits.
PCM\Ignition is high current circuit - fails, leaving instrument panel and accessory circuits functional, confusing troubleshooter(s).

Could also be Engine Shutoff Solenoid, top front on IP - easily replaceable - could be heat failure.

Could also be the IP fuel strainer\filter is dirty - worth a look while solenoid is out - remove the fuel inlet fitting.

Could also be IAT sensor failure, but that would give SES\MIL and DTC - does your SES indicator illuminate at key-on?

how much for a new engine shutoff solenoid???

just went outside.truck started up as normal.It seems to be ok after leaving off for a couple of hours.started the truck about 5 times in a row with no problem at all.....

shutoff solenoid is likely cheaper than new PMD but PMD is my guess.

pmd is what i think also.this is pretty much the same thing it was doing the last time it went bad..I think mounting th heatsink to the manifold was a bad idea.I've felt the heat sink after it was running a while and it was hot.I think this time im shooting for the left fender if i can some how make a harness extension for it.anybody know where i can buy the connectors at?? Im not paying $100+ for someones extension harness that couldnt take more than 1hr and $20 to make...

You could always extend it yourself. QM can clue you in on just how. Use solder to make sure nice'n tiddy connections.

No smoke, *sounds* like no fuel. No fuel sounds likey no PMD workie. Can verify on next failure, or next PMD. Next failure crack open an injector line and see if anyting comes zout.

You should be able to get the Driver with a new harness to soder on if you get it in the original box from stanadyne. GM doesn't see fit to pass that connector along with the driver. G'luck!

got in the truck this morning and it started right up drove for about 15min while i drove my son to school and it stalled once comming home.I dont think i'll be going anywhere today...
Abou the harness...Would it hurt anything if i cut the connector off the existing harness,Soder extensions on the the exisitng wires then soder on the connector to the new extension wires???I would also heat shrink over each connectins and wrap in flex tubing.

That's what I did and I'd like to have it scoped and compared to a stock harness pump mounted. Mine has been near flawless in it's performance over the last (?) year. 'cept I thought I was having fuel problems and it was stalling and coughing at idle like it missed an injection but when it stalled it always restarted but then got worse a soon as I was using the truck for the family instead of working. Trouble shooting the fuel system, I found it in good shape, so I looked at the next cheapest test, switched the driver to my #1 back up and I could hear a change in the idle. It had also had some intermittent cruise control as of late. I'm thinking that perhaps the vibrations had internally broken thier soder because the transistor nuts were real tight on the failing unit. It hasn't stalled or missed at idle since I put the backup driver in a few days back. This time I put a shock pad between the cooler to truck mounts.

i went and bought some rubber mounting pads at the hardware store id ill be using those to absorb the shock...
Im pretty sure i just mounted it in a bad place.after running for 30 or so i could feel the heatsink and it has hot..Im also going to try removing the underhood insulation..to see if that would help lower underhood temps.

I think in front of the engine bay is best and if you choose the right spot the fan will keep it cool at idle. If you know how to get the grill off it makes the driver quite accessable.

Actually some rethink on best location, after some testing this weekend with GMCTD looks like ultimate best place would be in bottom of inlet air filter box or inside fender prior to inlet opening, as long as engine is running turbo would be drawing cool air across fins, my bumper mount gets warm, 90F on a 60F day is what I measured surface temp of Heath's cool plate, on summer day say 100F may be 130 if 30 deg delta stays linear.

Air box or fender mount would be a bigger improvement for low speed driving with limited air flow across a cooler bumper or grille mounted.

Abou the harness...Would it hurt anything if i cut the connector off the existing harness,Soder extensions on the the exisitng wires then soder on the connector to the new extension wires???I would also heat shrink over each connectins and wrap in flex tubing. That is the best way to go! I paid $150 for someone elses extension harness and found it wasn't long enough to move the PMD where I wanted (front of radiator) So I just cut the one on it spliced in connections, soldered heat shrunk tubing and placed in wire loom and have never had a single problem and the PMD never heats up at all. Save yourself the $ and do it yourself for $10 in an hour. :D

thanks for the picture....
i think thats what im going to do....
both of the pmd's that i ordered came in now its time to mount...
Should i remove the plastic caps that are over the transistors or leave them on?And should i use thermal paste or paper.I bought these pmd's used so they didnt have the paper with them...
on my last failure i had removed both plastic caps and used thermal paste...I am going to move it off the manifold and somewhere cooler and want to make sure that i am doing everything i can to avoid the heat failure...
Thanks for all the responses so far...http://www.dieselplace.com/forum/images/smilies/rockon.gifhttp://www.dieselplace.com/forum/images/smilies/rockon.gif

Your guess is as good as anybody elses. For me, the paper was the easiest since it came with my new pmd.

Yes on pulling caps, no on paste, yes on heat transfer pads

well i made my own extension harness.temp routed the heatsink to the pass side of the engine.I mounted it so that the pmd is sitting in the hole that the air filter used to be in fender.I have a cone filter so that spot is blank.I ran the truck hard up and down a deserted access road up to 90mph with no pblms.Got back home opened the hood and felt the heat sink and pmd neither were hot at all.Pmd didnt even feel warm to the touch.I plan on mounting the pmd and heat sink in front of the radiator later in the week when i have some time...hopefully this will last longer than the last one did...

well i drove my turck back and forth to work today with no issues at all.It even seems to have a litttle extra umph...