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6.5L GMC. Smoking. 61k miles

N

Nowaydude

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Location
Ny
Hi: Im new to diesels, i came across a 2000 gmc 3500 with a 6.5l diesel engine, I picked it up cheap with a plow. The only thing I had to do was put 1 lifter in it, and put it back together, the lifter had went bad at 61k miles, I did not here it run befor buying it, it was apart.It starts right up and sounds ok but seems to smoke like its getting too much fuel. I haven't drove it yet, don't want to mess it up if too much fuel. Could it be a bad injector or something to do with the valve train everyhing looked ok on the rocker arms. If one or more of the injectors is leaking by, would I be able to tell by cracking the fuel line and see the smoke stop? I know the engine should stumble. Any Ideas? Thanks. Mike
 
Welcome to The Truck Stop, Mike.

I am sure some of these great 6.5 diesel guys will chime in about your issue with your truck, just be patient, some of them are probably up to their elbows working on a 6.5 or another project.
 
Welcome to the forum and nice find on the truck. Bigger kudos for putting it all together and getting it running.
The diagnostic checklist is a great place to start for running down new problems or, as I did, setting a baseline of 'what's what' on the truck as well as a means of educating myself on the 6.5 as I was a complete newbie.
Here's the link to it in the technical library https://www.thetruckstop.us/forum/threads/6-5-engine-diagnostic-troubleshooting-checklist.6300/

Obviously, you're no newb but, it's a good list and it works for the seasoned mechanic as well.
The smoke could be caused by any number of things so there will be a number of questions asked to help narrow it down.
Color of Smoke: White, Grey, Blue or Black?

Air Filter Condition: New, old but clean.

I'd type more but, I have to rescue my Burb from the A/C guys...compressor locked up...warranty saves some $$.
 
Ok thanks, air filter clean but old, seems like blues/white, ill double check it, i didn't smell and coolant smell. Thanks Mike
 
Hi: it was in the up position, I pulled on it it was hard to move untill i pulled off the vac line. Thanks. Mike
 
So now you need to determine if it's burning oil or fuel. What's the exhaust smell like? Black or more grayish in color
 
It's not black, i thought it smelled like diesel, not antifreeze, I think its light bluish, Ill double check tonight. Is there a water a seperator somewhere, im not sure how long it sat. Maybe fuel has some water in it? I put 5 gal of fresh diesel in and some diesel clean. Thanks. Mike
 
If it sat for long I'd dump the tank and drain all the fuel lines ..and Chang filter...refill and add some injector cleaner to the fuel..or tranny fluid .and yes crack the injectors 1by1 WITH IT RUNNING...check the hoses on the injectors... This is just personal thoughts... If it was over fueling it would be rolling black smoke... Hence the term rolling coal... I only say that because guys that want a bigger black smoke cloud behind there truck put programming in to give it more fuel than it needs.. only time I remember my truck smoking greyish-white is when my PMD was bad... Which controls all kinds of electronic crap under the hood.. if you're new to these engines you are in for an experience... Leroy diesel has a checklist of all the basic problems they have with these engines... Very good place to start getting it back into shape..and as anybody on here will tell you when it comes to electronics swear by ACDelco cuz these trucks will chew up and spit out just about anything else..there very picky.. out of curiosity what does it sound like when idling.. does she have the regular diesel chug or does she sound like she's about to die
 
PostScript... Never dealt with it myself on the diesel but wondering if a blown head gasket have the same effect on a diesel as it does on gasser... They usually blow some real pretty smoke with a blown head gasket..lol
 
I'm hoping not, but who knows, the smoke smells more like diesel and not antifreeze. It like when some diesels first start. Thanks. Mike
 
Mine didn't smoke with blown head gasket, it only pressurized coolant system and pushed it out overflow.
 
Whats a PMD? It Idles nice, doesn't sound like it wants to stall, it has that diesel sound klanging when running, it fires rite up and idles. I didn't see any moisture in the oil. Haven't looked at the coolant yet for signs of oil in it. It was raining last night so I wasn't able to work on it. Thanks Mike
 
More Links you're going to want to bookmark for research purposes.
Technical Library: https://www.thetruckstop.us/forum/threads/6-5-diesel-technical-library.589/
Parts Locator (Pictures and Diagrams): https://www.thetruckstop.us/forum/threads/part-locations.9494/
Acronyms: https://www.thetruckstop.us/forum/threads/acronyms-what-you-talking-about.11081/

PMD = Pump Mounted Driver which is an electronic module that relays instruction to the DS4 Electronic Injection Pump. Stock placement is on the driver's side of the Injection Pump (Pump Mounted) so the fuel running through the pump would keep the module cool...liquid cooling (two resistors inside run very hot). That only worked while the engine was running so the module would heat soak in 'the valley of death' and the cycles of hot-cold cause internal damages which is pretty much number one issue with the trucks. Most of us have remote mounted them which is where the term "FSD" for Fuel Solenoid Driver comes into play as it is no longer 'Pump Mounted'...semantics.
I had an occasion where I got a bit of oil in the cylinders and it smoked blue until it burned off.

Blow By. Most of our motors have some from engine/cylinder wear. Blow By is observed by removing the oil fill cap and dip stick with the motor running. It manifests itself as puffs of white vapor. Except for new or recently rebuilt motors, all will have some blow by, even if it is barely visible. If its looks like a steam locomotive though, you've got a tired motor.
You might want to conduct a 'Blow By' test. With a clear line running from the dip stick tube over the fender into a bucket of water (I stretch fitted the line over the mouth of dip stick tube for a good seal), increase RPMs to about 2000 RPM and observe the hose end in the water. If the water is pulled up a couple of inches in the tube, you're ok. No the water won't go all the way up and into the motor.
 
Thanks, Some one already remote mounted the PMD. I'll have to try that test, but the motor only has 61k on it, I was thinking I put something together wrong, I didn't have to pull the head to put the lifter in, I went threw the cutout in the head. I was able to get the old lifter out with magnets and then put the new one back in the same way, only work blind i couldnt do it gravity won't let you, I bought a Bluetooth fiber optic scope, used my phone ans a stiff piece of copper wire to guide it into the hole and in 20 minutes it was in. Thanks. Mike
 
$35. Amazon, I tried with mirrors for hours but you can't see in there, the Scope has an adjustable light on it, works really well. I don't care if I ever use it again, but I will Mike
 
Hi: I was finally able to work on the truck, cracked the injectors one by one engine would stumble or miss then when i tighten it up would smooth out, smoke looks like a grayish black and smells like diesel,smoke does not go away when cracking injectors. engine sounds ok. It has some smoke coming out of the valve cover PVC. I think, hose that goes to intake. Any Ideas? Probably should do a compression test. Thanks. Mike
 
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