White smoke on startup

[Blackmagic94]

One of the three trucks smokes for 30-90 seconds on first cold start then goes away, I understand it is fuel related, and possible cold start advance issues, what page in the TM would flow chart how to DG this issue for me

thanks

 

[Coffey1]

It's unburned fuel as long as it smells like diesel.
It's fine

 

[Blackmagic94]

I figured that but Im sure there is a way to correct it.

 

[Retiredwarhorses]

You most likely have a bad glow plug...it's not the cold advance, because the cold advance stays advanced for longer then 30-90seconds, it stays advanced till the engine temp hits 120 deg.

pull all your plugs and meter them, if fine then check your GP connections and voltages.

 

[Blackmagic94]

what should they meter at?

 

[doghead]

Why pull them to test them?

 

[doghead]

what should they meter at?

It should be covered in the -20 level TM.

 

[Blackmagic94]

Thanks

 

[Retiredwarhorses]

Why pull them to test them?

I pull, test and for the most part replace all the plugs with non-swell GP's on ANY new truck I get into the shop....be it mine or a customers.
another reason is to make sure none of them are swelled or the GP is seized in the head...once removed, I use anti- seize on the threads for easy removal later on....GP's are the number one source area of problem is this truck.

amd all this only takes approx. 15-20mins

 

[Blackmagic94]

Added a can of seafoam and the smoke is almost completely gone on cold start now.

 

[frank8003]

Seafoam is naptha, my Zippo works good on naptha.
Stoddard fluid/dry cleaning fluid, naptha is good expensive $tuff.
So seafoam cleaned up the glow plugs?

 

[Blackmagic94]

That or a stuck injector is my guess.

 

[doghead]

Did they all test good?

 

[Blackmagic94]

Havent had time to test them yet, just dropped a can of cleaner and drove it off road for about 30 minutes to burn it out.


When I get some free time I will test them anyhow.

 

[Retiredwarhorses]

If it has old fuel I would drain the tank as well and put in fresh diesel.
but white smoke is only 2 thing in a diesel...water vapor from a bad head gasket, or more commonly unburnt fuel due to a bad glow plug...always on startup.
black is excess burnt fuel...

 

[Blackmagic94]

Its not a head gasket the oil annaylisis showed neg results for antifreeze and water.

 

[Retiredwarhorses]

Just making a statement...but your the expert...what would I know about hmmwv's

 

[Retiredwarhorses]

Oh...after 20yrs working on these trucks, I have never fixed one from a can of some marvel mystery oil.

 

[swiss]

If it has old fuel I would drain the tank as well and put in fresh diesel.
but white smoke is only 2 thing in a diesel...water vapor from a bad head gasket, or more commonly unburnt fuel due to a bad glow plug...always on startup.
black is excess burnt fuel...

Interesting thread. I would like to add a few more questions. I have white smoke on startup only when temperature is below around 38 degrees F. That may be a resultant of being able to see it more but it is very evident. Would this temperature observation point to one cause more than the other. IE would the smoke mainly on cold startup be more closely related to the head gasket or glow plugs?

 

[Retiredwarhorses]

A little hard at that temp...your going to have alot of vapor anyway.
if its fine during warmer wheather...its most likley fine. If you store it indoors and start cols is easier to tell. Even my 98 turbo wagon stumbles when its that cold here in cali.
You could put in a block heater...cheap and they work great.