Hmmwv Blue Smoke and Stutter on Startup

RayGunSlayer

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Fort Oglethorpe, Georgia
Hey everyone, I’m just curious if anyone has had this problem before. So recently it starting getting colder here in north Georgia. Like dropping to the 20s and 30s at night. Well just yesterday I went to start up my 6.5 and it started by acted like it was only running on 6 or 7 seven cylinders for about 5 seconds and then ran perfectly after that. Well right as soon as I start it, and keep in mind this only started at the same time it started hiccuping during startup, it makes a small puff of blue smoke and then goes away completely after it starts running normally. I’ve revved it up right after it starts running normally and it won’t make any blue smoke at all. Starts and ends only with the weird startup. I’m at a complete loss. I’ll be checking my glow plugs tonight to see if any are bad. I just bought new injectors and glow plugs about 150 miles ago and everything ran perfectly up until yesterday. I also have the KDS Smart Start control box. Any help would be greatly appreciated!
 

papakb

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Get into your TMs and read up on the "cold advance" system. When the engine is cold a switch on the rear of the right cylinder head actuates a solenoid in the IP that injects a little more fuel when cold. Since it sits idle most of the time it can have problems working when it needs to. One of the symptoms is excessive smoke.
 

Mullaney

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Hey everyone, I’m just curious if anyone has had this problem before. So recently it starting getting colder here in north Georgia. Like dropping to the 20s and 30s at night. Well just yesterday I went to start up my 6.5 and it started by acted like it was only running on 6 or 7 seven cylinders for about 5 seconds and then ran perfectly after that. Well right as soon as I start it, and keep in mind this only started at the same time it started hiccuping during startup, it makes a small puff of blue smoke and then goes away completely after it starts running normally. I’ve revved it up right after it starts running normally and it won’t make any blue smoke at all. Starts and ends only with the weird startup. I’m at a complete loss. I’ll be checking my glow plugs tonight to see if any are bad. I just bought new injectors and glow plugs about 150 miles ago and everything ran perfectly up until yesterday. I also have the KDS Smart Start control box. Any help would be greatly appreciated!
RayGunSlayer , I don't own a HMMWV, but both of my diesel vehicles in North Carolina "rattle and clatter" for several minutes now that the weather has turned colder. I also noticed today that the "Intake Preheater" lamp was on in the M1088 at startup.

Member JD4044M installed a block heater on his truck in Washington state where they have already had snow. His noise and smoke went away with about two hours of heat before starting. Don't know for sure, but there may be a block heater for your 6.5 that would solve the problem. It just plugs into 110v and the "business end" inserts into a freeze plug hole in the block. The link below might offer some info worth knowing:

 

RayGunSlayer

Member
31
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Location
Fort Oglethorpe, Georgia
Okay so I did not get a chance to check my glow plugs last night but I most definitely will tonight. So this is what makes me think is it glow plugs though because this morning it was 27 degrees outside so definitely colder than the day before when this started. Well it took about 8+ seconds for it to start running normally. Yesterday evening, when I left work, it was about 55 degrees outside and it only took maybe 2 seconds before it started running normally. Well on these rigs the only thing that makes sense that would be temp related would be the glow plugs if some aren’t working. I’m going to for sure check them tonight and keep y’all updated. Plus I had someone mention to me about the cdr valve, the cdr is fine and working normally or it would be blowing smoke for more than just the initial startup.
 

papakb

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When your trucks exhaust starts looking like a mosquito abatement truck you need to start figuring out why.

However, with the cold start solemoid actuated a little smoke like this is OK for a minute or two but it should drop off as the engine starts to warm up.
 

Retiredwarhorses

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A proper working glow plug system should produce no smoke at startup.
I gets down past freezing where I live and zero issues on my trucks.
 

Milcommoguy

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Rosamond, CA
13 degrees last week... Started first time. No fussing, No smoking, No coughing. Diesel "rattle" with cold advance for 10 seconds to a purr.

Who said the desert was hot? CAMO
 

RayGunSlayer

Member
31
12
8
Location
Fort Oglethorpe, Georgia
Okay so I tested my glow plugs and one of my glow plugs was bad. Was swollen pretty bad from when I had bought the Hmmwv and it had one of the crappy PCBs in it. So got that changed and works perfectly now. Still find it strange that the smoke was blue from one glow plug not working. I know there is oil in the flue but it looked just like a motor burning oil
 

Mullaney

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Okay so I tested my glow plugs and one of my glow plugs was bad. Was swollen pretty bad from when I had bought the Hmmwv and it had one of the crappy PCBs in it. So got that changed and works perfectly now. Still find it strange that the smoke was blue from one glow plug not working. I know there is oil in the flue but it looked just like a motor burning oil
Not good - but at least you found the problem... I have seen several threads on here where glow plugs got "toasted" in pretty short order. It didn't really apply to me so I didn't dig in for more info. Might be worth a search and read so an early failure doesn't happen to you.
 
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