Cummins white smoke problem

[Cowboydiesel1988]

Ok here we go I'm new to the cummins world iv had two ford diesels an I just baught a 91 dodge with the 12 valve for a grand tha engine starts perfectly and seems to run fine to me but it is blowing white smoke when idling an smells like raw fuel when it's givin throttle it blows dark gray smoke I have no idea whats wrong an would be thankful for any help

[Curleyman]

haha it's a 12 valve cummins, a true industrial engine and your issue is fairly common. If it's a light white haze that goes away after a few min it's almost expected with a 12 valve. 12 valve fuel pumps need a little bit of fine tuning if you want to eliminate or increase the smoke. In my opinion 12 valve engines produce a charcoal gray/black smoke that not only smells far different then other diesels but also looks different. I personally love the smell

It is possible however that you have a leak somewhere in the lines and are sucking air into your injectors.

[Cowboydiesel1988]

it smokes the whole time the truck is running it has two fuel leaks that iv noticed before the injection pump could this be enough to cause it to smoke non stop? it doesnt seem like its running rough to me but i could be missing something im just hoping this isnt a serious problem

[KRB64]

Could be you have a bad injector if its white smoke all the time. You can try cracking them one at a time while running (with a rag over them!) and see which one doesn't make a difference to the idle. Remember to watch for the fan too...

[Cowboydiesel1988]

ok thanks for the advice il be sure to try that as soon as i can. could the main fuel delivery line having a small dripping leak contribute to the smoke

[KRB64]

My guess is that no - its under pressure so it wouldn't be sucking air, which is why it leaks out and not air in.

[W350_1992]

The internal timing got messed up on my injection pump causing lots of white smoke, so timing problems will make it smoke too.

[Cowboydiesel1988]

how could i tell if the timing has been messed up without tearing it down to check the gears? an when u said to crack the injectors u mean the fuel delivery lines on top of then correct?

[KRB64]

White smoke can be from unburned fuel, whether it dribbles out of an injector in the exhaust cycle etc.

With the engine off, make sure the bolts holding the fuel line to the injectors are freed up. Then, once running start cracking them one at a time. Fuel will start spraying out all over the place and the engine should start to miss and tighten it back up. When you do one and the engine idle doesn't change then you found your culprit. The procedure is just like bleeding the lines.

If this doen't make a difference then it could be something else. If it smoked when cold but the white went away after warm up it might could be timing. Someone with a little more knowledge needs to chime in here, I've told you about all I know, which isn't much.

From my experience I was running down the highway one day when all the sudden there was a cloud of white smoke behind me. I pulled over, truck seemed to run fine but the eshaust smelled of fuel. Drove her home and did the crack test and found a bad injectore. Good excuse to get six new 190s .

[W350_1992]

Originally Posted by Cowboydiesel1988

how could i tell if the timing has been messed up without tearing it down to check the gears? an when u said to crack the injectors u mean the fuel delivery lines on top of then correct?

The way I found that mine is messed up internaly is because mine sorta has its good days and bad days, meaning some days the engine is quiet, has good power, and doesnt smoke some days. Other days its noisy under throttle, doesnt have power, and smokes a lot.
Besides that, the timing gear might be off too because the engine runs best with the pump turned all the way from the head.

You can advance the timing 1/8" inch and see if it makes a difference, if it get worse then go backwards 1/8" and see what it does.

[Cowboydiesel1988]

hey guys i have another question probably a stupid one but if i took the muffler off my truck would it help or hurt it any an improve the sound any

[KRB64]

Whats a muffler?