Blue smoke observations...Ideas?

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Greg5OH

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Feb 24, 2017
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Some observations about my heavy blue smoke.


15 deg timing, injectors are good, compression good, grid heater works.

Trucks starts quick, lets out a big plume of white/grey smoke. This is fine as its cold and got some unburn diesel.
runs rough for a few seconds needs some pedal to keep it running then smooths out.

Within 10 seconds thick blue smoke starts rolling out and will continue hazing blue (not whitish blue, pure blue) until the temp gauge starts moving past 120F.

Zero smoke when warm.

The smoke lasts far too long for it to just be valve stem seals.

I noticed if i start driving within 30-60s after initial start, the truck will run super rough if i give it more fuel to accelerate. will misfire heavily and roll a ton of blue smoke. This also makes me think it is not valve stem seals..

Any ideas?
 
Yes, clean on intake side, no axial play, just regular soot on turbine side.
I had my intake horn off couple weeks ago and no oil in there either.
 
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no, does this anywhere from -10 to +60. Bought the truck Nov 2016 so have not operated it in summer temps.
the colder it is the heavier the blue smoke is.
I am in MI.

Also has a new mech fuel pump, new filter, and new OFV from Larry B
 
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An interesting piece of info too:
the engine is super docile and quiet whencold started.
Sounds like an old merc 300sd. just smooth purr.
Its not untill its up to temp that it has the characteristic cackly snappy 12v sound these are known for...
Blue smoke, misfires when cold and lay into the fuel (pops smoke rings out the exhaust..), sounds like super retarded injection timing?

Can a Ppump dynamicaly retard the injection timing somehow?
 
Does the smoke smell like oil or fuel?

Have you tried cracking one injection line at a time to see if the smoke changes?
 
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^i have not tried cracking injector 1 by 1. Something to try for sure.
To me it smells like fuel (the exhaust)...
I know burning oil smell, it is quite acrid...this just smells like cold diesel really...
and my oil level does not change.
 
I would bet that you have an injector nozzle dripping, or a plunger sticking. Most likely an injector.
 
how come it did that with brand new injectors too though?
I then ultra sonic cleaned my stock ones and same deal.

a plunger sticking...are these plungers in the pump?


the odd thing is..arent 12v supposed to be stupid loud on cold start too? Why is mine so quiet.

thanks for the responses keep em coming. Im sure this issue will be resolved in no time with your help!
 
Well, if you've tried another set of injectors, there is no chance that an injector is the issue. Cracking the lines may point you to an issue with the pump though.

It definitely sounds like a fuel issue to me.
 
^yessir me too.

Im not one for additives but another interesting note,
i tried liqi moly diesel purge originally as the first thing in a closed loop (bypass the fuel tank)
cold engine, once the liqui moly hit, there was no oil smoke for 5 mins. drained the can, hooked lines back up to the tank, and then the blue smoke started again.

I almost dont want to mention that as it throws another wrench into the equation, or simply the additives in it burn so clean that the underlying fuel issue does not matter. But maybe that piece of info will help someone.

going against my convention, this mornign i threw in a bottle of power service, going on a long drive tomorrow, well see on sunday when i fire it up after sitting overnight how the smoke situation is..

that being said, if it is still smoking sunday morning, Ill try cracking the injectors 1 by 1
 
some more info i observed yesterdsay during my 350 mile trip

sometimes when i idled it hazed blue...other times not.

then sometimes when i free reved it (stab of the pedal) it would stumble misfire and cough hard, shoot white and blue smoke everywhre

other times it woudl free rev completely fine to whatever it should rev to (i dont have a tach)...
replacing fuel filter on monday but i doubt thats it..

could it be a fuel starvation issue? remeber, new larry bs overflow valve isntalled.
 
I just skimmed but have you tried a fuel filter? What is your fuel pressure?

Also PPumps don't like to free rev. I've had some that can free fine without popping and sputtering and others that pop and sputter terribly.
 
Have you verified timing is set correct and hasn't slipped?
Part of your symptoms kinda sound like retarded timing.
 
That sounds just like when an overflow valve spring breaks, have you checked that.
 
yes it is verified at 15.5 deg timing.
ofv is new from Larrys Bs.
i do need to get a gauge on there..otherwise we are just shooting dice..
new filter going on tonight.

could it be a clogged fuel pickup screen??
 
WUnderwood said:
Lets see what the fuel pressure gauge says, otherwise, we are shooting in the dark.
Click to expand...


Isn't that how we roll? I mean, if everyone was able to follow proper troubleshoot processes, we would not be here.
 
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