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first off hello from delaware. i have been working on gas motors/trucks now for a little time but this would be the first diesel i have touched. but anyway me and my buddy just picked up a "work" truck in its previous life it was ... JOIN NOW TO REMOVE TRACER

1996 6.5td idle problems

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Old 09-11-2013, 06:59 AM
Diesel Enthusiast

Default 1996 6.5td idle problems

first off hello from delaware. i have been working on gas motors/trucks now for a little time but this would be the first diesel i have touched. but anyway me and my buddy just picked up a "work" truck in its previous life it was a plow truck. but the body isnt that bad off, shes been parked for the past couple years. then my buddy who owns a welding shop needed another work truck. he has his 04 chevy v10 and my 94 c1500 4.3 its ok for small runs but if we need to haul anything with weight we have to use his 04 or my 79 k20. but my k20 is limited due to 6" lift and 40s. and his 04 doesnt get good mpgs with the box on the back and welder and tools so we need/wanted a diesel was planing on getting a cummins and dropping it into a 89 3+3 but this deal cam along and we picked up this 96. but the problem is/are the glow plugs seam to be messed up. i dont know the full details but my buddy looked at them and said the harness seams to be melted or something. so anyway we tried to start it to get her loaded on the trailer. took about 10-15 seconds of cranking to get her to fire up. once she did she screamed to 2k then back down to about 1k then a couple seconds continued this cycle. during this run she would blow black smoke then white/maybe gray smoke this was alternating with the rpms. dont recall which smoke went with which rpms but it was changing. after 10 seconds of this we shut her down. started to look for other problems. both of us can work on any gas motor fine he has more experience than me in diesels but its not much. so while we where cranking on her i recalled not hearing the lift pump with the key on. so we checked it no power to it. replaced it with one we had and ran a jumper wire to the battery. bled the line and started to crank still same results. now i know the body looks ok with rust but the bolts seam to be hurting, so could this be a ground problem? from what im reading it seams like IP. the pmd is relocated so its not stock but it could be bad. need to find a working one to test her with. but till i find one im looking for other things that could be a problem. i dont know but i think my buddy said the throttle light was on, and when it was doing its thing there was little to no throttle response. now on a side note we had to start her by jumping the starter ( it was getting power but thats it) the guys father came out and told us the PO knew the starter was bad but he didnt want to put any more money into her. he did act surprised when we did get her started and she ran like crap. so till i get a response here i will continue to search for similar problems.

---AutoMerged DoublePost---

quick question, how important is it that the batteries be matching?

Last edited by Irish_Alley; 09-11-2013 at 06:59 AM. Reason: Automerged Doublepost
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Old 09-13-2013, 06:40 AM
Mayhem's Avatar
Diesel Wrench


[---AutoMerged DoublePost---
quick question, how important is it that the batteries be matching?[/QUOTE]

This is very important just had a battery go bad and replaced both

Mayhem's Sig:1993 Chevrolet K2500 6.5 Vin code F
PMD Delete
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Old 09-13-2013, 06:57 AM
Diesel Enthusiast


years ago i used to work at autozone and we used to always push replacing both batteries but never knew why . thought it was more about money, but what type of problems could this cause?
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Old 09-15-2013, 12:29 AM
Diesel Enthusiast


ok just a small update. while i was sleeping today (work 2400x0800) my buddy started to work on the truck and said the plug for the pmd was melted. so this could be the problem now just to find another friends to borrow
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Old 09-15-2013, 08:29 AM
Mayhem's Avatar
Diesel Wrench


Take apart and clean a grounds especially the ground strap on the rear of the passenger side head get starter checked and clean the block where the starter bolts to it a little grase here will kill a starter fast and that truck being from the north you need to check the oil cooler lines real good where they connect as the clips are prone to failure due to road salt 30 seconds without oil and bye bye 6.5
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Old 09-15-2013, 02:48 PM
detroitdiesel idi's Avatar
Diesel Enthusiast
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First off chevy didnt have a v10 engine in 04. 2nd the lift pump runs off oil pressure not volts. Symptoms are most likely pmd.

---AutoMerged DoublePost---

If its not relocated

detroitdiesel idi's Sig:1992 c3500 chevy scottsdale single cab long box 12 valve nv4500 conversion
1993 k3500 ext cab long box 6.5 diesel automatic project sold
2002 blazer 4wd 4.3 winter ride
In the market for a clean jetta tdi standard shift
Natef/ase certified diesel mechanic

Last edited by detroitdiesel idi; 09-15-2013 at 02:48 PM. Reason: Automerged Doublepost
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Old 09-15-2013, 04:27 PM
racer55's Avatar
Diesel Bomber


Ok lift pump gets power through the lift pump relay and should have a prime cycle when the glow plugs are cycling.
The OPS is only secondary backup power for the LP and usually only is used for a few seconds after shutdown while the oil pressure bleeds off.

Check for power to each and every glow plug when they cycle,if the harness is suspect(unplug them all and jumper the relay heavy terminals).

There are a lot of fusible links for the glow plugs that can fail if shorted in the factory harness-you need working glows to start it at all times of the year.

If the age is unknown replace with Bosch Duratherm glow plugs.

Also an often unknown procedure with new owners is that you need to crank the engine over as soon as the glow light goes out the first time-the additional short glow light cycles are afterglow and mean to happen with a running engine.

If you wait for the glow light to go out the final time before starting,the glows will be too cold to aid in starting.

When you replace the PMD make sure you install a resistor in the harness cavity-if the old 1 can retrieved use it.

Also make certain that heat transfer paste/pad are used between the PMD and heatsink and torque the mounting screws to 25 inch pounds.

Your symptoms of a racing engine can be a defective PMD or a failing IP but get the codes pulled and diagnose the service throttle problem first.

Also verify that the turbo wastegate is operating-running these with no boost can cause serious damage.

Matching batteries is good to have but not a deal breaker-the problem comes when a bad battery kills a good 1-also 700+ CCA is minimum requirement and more is better in cold climates.

When it comes to batteries-check the catalog for whats available in the case size you need-find the highest CCA available,then pick 1 size down.

The reason being is on the highest CCA you can get for a certain case limits electrolyte volume because lead takes up the space and thinner plates fatigue sooner killing the battery- 1 size smaller will give near equal power and last longer in most cases of liquid filled battery's.
Gell cells are a different animal though.

And last but not least-please hit the enter key on occasion when posting,sentences are a lot easier to read than big paragraphs.
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Old 09-16-2013, 06:02 AM
Diesel Enthusiast


Lol thanks for the tips. And sorry about the big paragraph get carried away sometimes. But I dunno why I put v10. Guess I was tired and trying to think of his engine size might just be the 8.1 but it might be just the 6.0. Sorry for the confusion, and thanks for pointing it out
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Old 09-21-2013, 05:35 PM
Diesel Enthusiast


OK a little update. Don't know when but we didn't realize it to after we got her home. But the pmd box melted at the plug

So order new one. We know the pmd box got warm before when we had her running but reason for checking the box was because we couldn't get her to run at home. Then checked the pmd box it wasn't warm at all. So put a new one and wire harness on. Now its still not getting warm and still not running.
Checked all fuses all good. Replaced starter due to a bad solenoid. Now lift pump works when you turn the key. The pmd box is getting power don't know what plugs do what but it's still not getting hot

---AutoMerged DoublePost---

Forgot to mention Idk but it could be possible that someone might of left the key on. Could this fry the pmd?

Last edited by Irish_Alley; 09-21-2013 at 05:35 PM. Reason: Automerged Doublepost
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Old 09-22-2013, 10:39 AM
racer55's Avatar
Diesel Bomber


Should not have an effect.

PMD must be mounted to an aluminum heatsink large enough to dissipate the heat the PMD generates when operating.
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