SMOKE decoding!!

[Tomeygun]

heres the situation,

65 degrees outside

truck sat from 9 am till 5 pm,

start truck and black puff followed by WHITE puff...



couple light taps to pedal = black turn to white puffs right behind eachother...



after 20 seconds or so, no puffs with pedal tap...



should i be worried about white smoke?



is oil smoke blue or white, and is it that hard to tell which it is?

Thanks

 

[Shovelhead]

Blue smoke = oil

White smoke = water/condensation

Black smoke = POWER

 

[BigYellowIron]

Tommy what dealer are you working for in St louis?



Adam

 

[rspinks]

blue smoke

Does diesel combustion make blue smoke when it's cold out? I mean my truck makes PILES of blue smoke before it warms up when the temp gets down below 0c / 30f or so. It's brand new basically and I know lots of other new ones that make blue smoke on startup in cold weather. I even noticed a Dmax smoking blue in the parking lot at the local sledding spot on the weekend.



Is this diesel combustion smoke or is it engine oil getting burned? I've had people tell me it's fine and others say it's not (even a Cummins tech said he didn't like it even though their shop Ram does it also).



Rich

 

[msamoy]

I thought that in diesels, white was more commonly associated with unburned fuel. The blue though, that would concern me . .

 

[rspinks]

Concern immunity

If I let all the problems I read about here concern me I'd be dead from anxiety within a few months. Lift pumps quitting, transmission's grinding, clutches slipping, blocks cracking, track bars falling off, holy night you'd think these things were lemons! Seriously I think this sight is great because it covers these things in obsessive detail, but I try to take things with a grain of salt to keep my sanity.



I've seen lots of other diesels burning blue in cold weather on startup, even brand new ones so I'm not too worried. I would like to know the science behind the blue smoke however.



Rich

 

[jwgary]

When it's cold outside, there isn't always enough energy to completely burn the fuel. The flame dies out and what you are left with is the blue cloud of unburnt fuel vapor. When you are running warm and you dump in a whole lot of fuel, you cant burn all of it, but it does go through the flame. The flame changes the properties of the fuel and makes it turn black.

 

[rspinks]

Allright!

That's what I wanted to hear, ie: that the blue colour comes from unburned diesel, not engine oil. Thanks.



RS

 

[Tomeygun]

Originally posted by BigYellowIron

Tommy what dealer are you working for in St louis?



Adam

i work at Lou Fusz Dodge in Kirkwood, MO, New Auto Sales



Glad to hear i am not the only one with blueish/white smoke upon cold startup.

 

[MCummings]

Originally posted by jwgary

When it's cold outside, there isn't always enough energy to completely burn the fuel. The flame dies out and what you are left with is the blue cloud of unburnt fuel vapor. When you are running warm and you dump in a whole lot of fuel, you cant burn all of it, but it does go through the flame. The flame changes the properties of the fuel and makes it turn black.

That's the long way of saying your EGT is to low, bring your EGT up and the smoke will go away.



Thanks for the explanation jw



Merrick Cummings Jr

 

[RustyJC]

A diesel depends upon the heat generated by compression to ignite the fuel. Therefore, the temperature in the engine cylinder at the start of injection is critical.



The universal gas law says that air temperature will increase as a function of pressure as volume is reduced (i. e. , the piston is moving up on the compression stroke. ) It also says that the temperature of the air being compressed at any point in the piston travel is a function of the air temperature at the start of compression.



Therefore, if ambient air temperature is low and the engine is cold, the cylinder temperature at the start of fuel injection is not high enough to achieve efficient combustion, and the grayish/white smoke cloud results. As the engine warms up, the cold incoming ambient air is warmed by heat from the turbocharger, intake manifold and port, cylinder wall, head, piston crown, etc. , and the smoke disappears.



If you think a 5. 9L Cummins can generate cold start smoke, you ought to see a Cooper-Bessemer LSVB-20-T diesel fire up on a cold day - 20 cylinders, 15-1/2" bore, 22" stroke, 24" diameter impeller on the turbocharger! Now that baby can fumigate the neighborhood - that's one of the reasons they generally have circulating crankcase oil and (depending on the location) coolant heaters to keep them warm when they're shut down. In very cold locations, some are plumbed to use engine coolant to warm instead of cool the air-to-water aftercoolers at light loads to keep the intake air warm enough to avoid combustion problems.



Rusty

 

[rspinks]

Rusty

Very informative, obviously you have a strong thermo background. Does that Cooper generate blue smoke in cold weather? You said grayish white.



RS

 

[MCummings]

Okay,, yall have priqued my interest.



What makes tires smoke??



Why do some tires white smoke instantly when spun and some only give off a whisper of smoke after several seconds. ??



Since this MIGHT be related... What makes some tires squell very loud and some not at all ????



Thanks in Advance,



Merrick Cummings Jr

 

[RustyJC]

Re: Rusty

Originally posted by rspinks

Very informative, obviously you have a strong thermo background. Does that Cooper generate blue smoke in cold weather? You said grayish white.

RS,



OK, OK, it's grayish white with a blue tinge to it!



Rusty

 

[rspinks]

OK, just needed to confirm. At -25c with no block heater my truck makes distinctly blue smoke. It drifts along in clouds and lingers for awhile in the air, unlike the white water vapour that disappears quickly. Hopefully sometime I will be able to make the most coveted of smoke, the black stuff like I see pouring out of Merrick's stacks from his pic's.



Merrick I think the white instantaneous smoke when you start a burnout may be caused by moisture on the surface of the road that evaporates quickly. Then the blue starts to roll off the tire surface as the rubber gets hot enough to melt. Sometimes it takes longer to get blue smoke when the road and/or tires are cold and they take some time to absorb the heat of friction.



Dunno on the squealing thing. My buddy once did a burnout with his streetbike on a large piece of styrofoam - man that was the most hideous screeching sound I ever heard!



RS