doomgaze

I've read where some white smoke when you start the truck on cold days is normal. My question is how much is normal?

It's been pretty cold around here the past few weeks and when I start the truck (don't have a way to plug it in) I get a constant stream of white smoke until the engine is warm. I let it idle for 10 minutes or so today and for a while going down the road I still had a steady steam of white smoke pouring out the back. It's not blue tinted or anything... just white.

And I noticed something tonight that I haven't before. However, its also the first time I've really done anything like it... Going down the interstate I had the cruise set at 70mph. Engine was plenty warm, right at the middle hash mark. Thing is, I decided to give the engine a little work out so, with the cruise still on, I pressed the accel pedal slowly, but steadily, and I looked back in my mirror and there was a pretty good sized white cloud behind me. So I did it again and the same thing happened. And again...

Is this normal? I've always had the mentality that any white smoke is bad smoke so I figured I'd check with you guys.

Thanks

spudman

thats not white smoke it's water vapor much the same as a gasoline engine on a cold day.

phox_mulder

Better not be.
Water is not a byproduct of Diesel combustion.

Most likely it is just unburnt Diesel.
Cold engine, not complete combustion.

It should clear up after a few minutes though, how cold is cold?


phox

doomgaze

It was 16*F today. It's been anywhere from 20* to a low of 0*.

I thought unburnt diesel was black in color... am I mistaken?

phox_mulder

Different but yes.

Black smoke is soot: a lot of fuel, a lot of heat, not enough air.

White smoke is atomized fuel: right amount of fuel, right amount of air, just no heat to burn it.

You could also have white smoke after it's warmed up if the timing is off.
Fuel is being injected to late to be compressed and ignited.

Timing is all electronic in the 24 valves, so the culprit would be the injection pump.

Cold morning white smoke should have a blue tinge to it, as Diesel is in fact oil and you are burning it.


phox

Gypsyman

I noticed when I was driving back from Alaska that when the temp dropped below 20* I would start to see a small cloud of grayish white coming from my exhaust. The further below 20* it went the larger the plume got but as soon as the temp came back up to 25*+ it was gone. Seems to be the nature of the beast in my opinion.

Richard

handymantim

I noticed while cruising with the cruise control and then stepping on the accel pedal that the engine "gets confused". The cruise control is telling the engine one thing and the driver another. The engine will accelerate but it does it more slowly. If while accelerating using the pedal you kick off the cruise control it will lurch forward.

I'm curious if you try the same cruise control/pedal combo, get white smoke, and then hit the "cancel" button on the cruise control with your foot still depressing the pedal if the white smoke will disappear.

doomgaze

When I press the pedal with cruise on it was just one large puff of white smoke no matter how long I held my foot there.

doomgaze

Hope Richard is right in that its just the nature of the beast... but I may have it checked out anyway. Couldn't hurt.

Gypsyman

Since mine is an '03 and I haven't seen one of the newer units with the "white smoke" problem I would definately have it checked anyway just to be safe. What I'm referring to is just a small plume from the pipe in cold weather that dissipates quickly. Similar to the steam plume you see while following a gasser as it warms up. Hope this helps as a visual reference to what I have seen from my truck.

Bottom line. When in doubt, have it checked and logged in the vehicles history just to be on the safe side.

Richard

bkrukow

The smoke at start up is normal in the cold. Mine does not do it every time but it will ocasanaly smoke like mad for a while if started cold. The smoke while accelerating is also normal in the cold. It most likely is not nesasaraly smoke but watter vapor as suggested. If you live in an area that has high humidity like around here then it is highly likely thats what it is. Mine will blow watter vapor every time I accelerate no matter how warm the engine. As Phox said it is not a byproduct of diesel combustoin but around here it is a byproduct of having an air intake. Even with the temps at the -10 to posotive 20 deg range lattely the humidity is still around 40-60%. At that high of humidity all engines blow watter vapor while running. I went to collage to be a mechanic and they told us that around here in the summer when the humidity is at its normal 85-95%, 1 gallon of watter goes threw the engine and out the tail pipe for every gallon of gas burnt.

phox_mulder

Good to know, I hadn't thought of that.

I just knew that water wasn't produced by combustion like a gasser does, hence the exhaust system hanging around a lot longer, not rusting away from the inside out.


phox

doomgaze

Good information! Thanks guys