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White smoke at start up

51K views 51 replies 21 participants last post by  Schwind 
#1 ·
I need to track down why my truck has excessive white smoke at start up. The smoke smells like raw diesel, not coolant. Once warmed up the truck does not smoke. The glow plugs and system are good. The injectors have been replaced. The cooling system is OK and upper radiator hose is not hard. The cold temp sensor is working and when jumped , makes no difference with the amount of smoke. I need to figure this out soon or I will need to sell the truck. Other than this problem , the truck runs well. Any suggestions are welcome.
Thank you
 
#3 ·
May need to have the injectors tested. Just because they are new or have been replaced doesnt mean they are good. Only other thing I can thinking is maybe injector pump timing??
 
#5 ·
Someone correct me if i am wrong but I do believe it could be off time enough to run and start like crap but run ok when warm. Altho it will perform/run better all the way around when the timing is reset correctly.
 
#6 ·
I'm experiencing the exact same problem. I also have replaced the injectors, glow plugs, lift pump, PMD, CTS, and yesterday I tried the "optic bump" out of desperation. Nothing has helped so far, but I'm gonna keep trying. WHEN I figure it out I'll be sure to post it because there are a handfull of other people having this problem.
 
#8 ·
Sounds to me like you might have an injector leaking down. My truck has been doing that a little - but it's more of a very light blue/white smoke - but it smells like raw diesel - just puffs it out on cold starts. I need to replace my injectors soon.

What brand of injectors did you install?
 
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#9 ·
My truck belched out the whitish smoke prior to and since I replaced all the injectors. I really hate throwing money at this unless I am sure it will take care of the problem. I remember someone once telling me that there could be air in the system, but that never made much sense to me. Please, keep throwing ideas out at me.
Thanks,
Heirotto
 
#10 ·
LOL... You been reading Ron's posts again... "air in the system is the root of all evil."

Air in the system after the IP can prevent fuel from getting to the cylinders... it's compressible, and so a block of air in an injection line will prevent an injector from opening properly until that air is worked out. If you have it, it'll work itself out. At worst, you may have to bleed your injectors by cracking the nuts loose one at a time while it's running.


Air in the system before the IP can affect the operation of the Optic Sensor as well as making the fuel delivery uneven (since the IP may not be getting a 'pure' flow of fuel, it may not pump the same amount of fuel at each stroke.

Air in the system will NOT cause the thing to 'airlock', unless your LP is shot. This is not a system where the IP "sucks" fuel up from the tank... an airleak in a gasser will prevent fuel from being pulled to the top, but these trucks should self-purge that air. You can check for air in the system BEFORE the IP y installing a piece of clear tubing between the filter and the IP... look for bubbles. Bubbles are bad.

In any case, air will not give you excess fuel in the cylinders, which is what you seem to have happening.

Have you thought about glowplugs? One bad glow plug will cause the symptoms you describe.
 
#11 ·
I think it is your timing chain. i had the same problem and replaced the chain. it is like having a new engine..
 
#13 ·
His sig says 167k
 
#16 ·
my 93 done the same thing(when i put the engine in) would smoke so bad you could see the truck...replaced IP and has never smoked again...
 
#18 ·
Heirotto,

try first to re-time your injection pump, i think that with the miles you have on your engine the timing chain is stretched, so is the timing from the injection pump
 
#19 · (Edited)
I will jump in here too. I have a 1995 6.5TD Suburban and have a very similar problem. The thing is that the smoke comes out while cranking, but immediately goes away when it starts. I watch my oil pressure and the motor will catch when the pressure comes up which makes me suspect that I need to mod the truck so the lift pump will run when cranking, but that still doesn't explain the initial smoke. From this thread the most likely culprit seems to be fuel in the cylinders on startup. The engine just had new heads installed and was checked last week by the shop. All is tight. Heath diesel is recommending injectors be replaced every 100k miles but that is a bit of an expense and I am getting conflicting advice on whether that is even necessary. There are 169K miles on the truck now and I don't know if the injectors have ever been replaced. I am thinking glow plugs next.

One note of interest is that I have not moved the PMD. That is next on my list when I have the dough (which is why I am not anxious to replace the injectors yet). Any chance this is a PMD issue? Doesn't seem to make sense since it is a start-up thing and there is no heat yet.
 
#20 ·
I have a 1996 3500HD dump truck. bought new. It has always put out a puff of white smoke and a shake on start-up. The lousy dealer (when new) couldn't find the problem. Claimed that it didn't do it for them. I left it several days...liers. The truck has 88,000 miles on it now. I only drive it 3,000 miles a year lately. I can't really count on this truck, although its been years since it died on the side of the street. I just cross my fingers and drive.
 
#21 ·
I have bumped up the timing. I rotated the injector pump 1 line width towards the driver side. I am unsure if this helped the smoking situation, it certainly has not eliminated it, so I would like to advance it a little more but I am not sure how far is too far. Any advice is appreciated.
Thanks,
Heirotto
I now have 200K on the engine
 
#22 ·
you advance it to high and it will scare you this winter....
 
#23 ·
I have an 06 and mine smoke when the high idle was on. It blows out white smoke for couple of mins and when its done blowing the smoke, thats a sign my truck is warmed up..during the summer when I start it ,,it doesnt smoke at all..only during the cold winter start ups...and my truck is running perfect..just my 2 cents..
 
#24 ·
Have you checked for power at the glow plugs? A bad connection or blown fusible link is a possibility. Oil running down the valve stems due to bad seal too.
 
#25 · (Edited)
Mine does this at cold start too. It will run rough and will not rev up, then something happens and it will rev great and smoke will instantly clear. I am really suspecting the optical sensor. It is like something is stuck and then frees up and would have to be something controlling timing advance. I wouldn't mind buying a new sensor if I knew that is what was causing it but would like to try a different (used one) to confirm that is the problem.

I have new glows, gp controller, injectors, heath chip and everything is working properly there. If someone has a old optic sensor that is likely still good in a old IP I wouldn't mind giving it a try.:cool:
 
#26 ·
Is your cold advance on ip working? It should rattle pretty loud for 1st 3-5 min. then quiet down and idle speed drops.
 
#29 ·
The mechanical pumps have a cold advance. The electronic pumps do it electronicley with the stepper motor. This thread is dealing with mechanical pump. The wire that runs the advance is green. It also goes to the fast idle sol. There is a temp. switch on the passenger side head above #8 injector that tells the pump to advance and sol to go to fast idle.Temp sensor on coolant crossover may also have input to ecm to activate cold advance.
 
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