White smoke in Diesel

[Caolan]

Originally Posted by a64pilot

If steam, then it will very quickly dissipate.
However a cold Diesel it's very common to have white smoke at start up, that is unburned fuel.
A little extreme example, but does illustrate the point.
Do you have glow plugs?

Yes to glow plugs.

[Caolan]

Originally Posted by Caolan

Yes to glow plugs.

The buring smell is what is new to me.

[a64pilot]

If you have glow plugs, then inoperative glow plugs could be it.
They are easy to test with a multimeter. I start with the easy and inexpensive stuff first.
The plastic smell I assume may just be fuel vapor odor, that is a guess though

[a64pilot]

Is there plenty of water flow in the exhaust?

[Caolan]

Originally Posted by a64pilot

If you have glow plugs, then inoperative glow plugs could be it.
They are easy to test with a multimeter. I start with the easy and inexpensive stuff first.
The plastic smell I assume may just be fuel vapor odor, that is a guess though

I would assume though that after the engine warmed up that I would have the same issue then when restarting the engine.

[Caolan]

Originally Posted by a64pilot

Is there plenty of water flow in the exhaust?

Oh yeah. Normal amount of spitting out the rear

[a64pilot]

Originally Posted by Caolan

I would assume though that after the engine warmed up that I would have the same issue then when restarting the engine.

No, once warm there will be no un-burned fuel, so no smoke.
Diesels of course run off of the heat of compression, to augment this heat some engines require glow plugs, however once warm, the heat is there already, so no smoke on warm engines, just cold ones.,
First check for voltage to the glow plugs, then to test individual plugs you have to disconnect them from the circuit and test resistance, a burned out plug will be an open circuit.

[Gary Matthesen]

Tell me what you got in the summer when its warm. Right now your shooting real cold water into hot exhaust at the mixing elbow. That's gonna produce steam. Just one thought I observed confirmed by the guru Nigel...

[grantmc]

Originally Posted by a64pilot

Check my math, warning I am bad at math so check it.
16 oz bottle treats 460 gl of fuel
there are 128 oz in 1 gl, so therefore 460 gl is 58880 oz
divide 58880 by 16 gives a ratio of 3680 to 1
divide 3680 by 128 to turn oz to gl gives you 28.75

so if my math is right, one oz per 28.75 gl is perfect for the "kill ratio" so put 1 oz per tankful

Is that a US or imperial gallon?

I am so thankful we have the metric system.
At least a litre is a litre wherever you are, and dividing and multiplying by 10 so much simpler.

[Teknishn]

Originally Posted by Scot McPherson

Air getting into the fuel system should shut the engine down. Not a whole lot of diesel engines continue running if there is a stream of air flowing into the fuel lines.

You are absolutely correct. However, I have had flex fuel lines that would allow a bit of air in, not enough to shut down the engine, but just enough to cause the air-to-fuel ratio to be a bit off.

Had this happen to me on my current yacht repair/restoration project (boat built in '36). Chased the problem for weeks thinking fuel pump, head overhaul and then noticed a very slight moist spot on a fuel line about 3-meters aft of the engine. Replaced the hose and Voila! Engine is running smoke free! (Cheap Chinese crap hose with fittings installed in Egypt.)

[a64pilot]

Originally Posted by Gary Matthesen

Tell me what you got in the summer when its warm. Right now your shooting real cold water into hot exhaust at the mixing elbow. That's gonna produce steam. Just one thought I observed confirmed by the guru Nigel...

That explains the white smoke that dissipates very quickly when your underway, but not white smoke that starts immediately with a cold engine, but goes away within a minute and does not reoccur until the next cold start.
One key difference is how fast it dissipates, steam is almost immediate, fuel vapor takes a little longer.

[Scot McPherson]

Originally Posted by Teknishn

You are absolutely correct. However, I have had flex fuel lines that would allow a bit of air in, not enough to shut down the engine, but just enough to cause the air-to-fuel ratio to be a bit off.

Had this happen to me on my current yacht repair/restoration project (boat built in '36). Chased the problem for weeks thinking fuel pump, head overhaul and then noticed a very slight moist spot on a fuel line about 3-meters aft of the engine. Replaced the hose and Voila! Engine is running smoke free! (Cheap Chinese crap hose with fittings installed in Egypt.)

Your statement reminds me of an issue I had with my engine this past december. I had just bought the boat. We test ran the boat around narraganset, and pulled back in. I wrote the check for the boat, and for the next two weeks I outfitted the boat for a December voyage north to Maine (where I am right now). Took off for maine when ready, and the engine ran for about 2 hours before it started losing RPMs and then finally quit. After the engine was fully cooled, I could start it again and it would run like a top for another 30-60 minutes. Rinse Repeat over and over.

Thought it was tiny amount of air locking the fuel up, thought it was collapsing lines. I finally gave up and had a real mechanic look at it. He asked me when the last time I fueled up was? I said never, I just bought the boat. You sure? yes I am sure. There is gasoline in the fuel...WHAT???

The dude who sold me the boat did me a solid and topped off the tank, but didn't double check which pump he was handed. Sigh....Luckily it was just enough gasoline to cause the engine to lose power when it reached full temp, and not enough to damage the engine. It just started to preignite just enough to be unable to keep running.

had mechanic throw an aux tank in there for me to finish the trip with (he wanted WAY too much to flush the tank), and I did the job up here in maine this winter after I arrived. Engine runs perfectly now.

[nortonscove]

My brother inlaw is quite the diesel mechanic and when I asked him he recommended running it hotter by upping the rpms. Did this a voila no more smoke. Noticed the same issue on our tug. Seems worse in cold weather. Often took half an hour to see the difference in winter.

[Astrid]

I'm with a64pilot on this question. I get some white smoke on start up mostly when the air temperature is cold and humidity level is high. After a few minutes warming up the white smoke goes away.

[DeepFrz]

Two things don't appear to have been addressed. What do you mean by "sludgy" fuel and where is the smell coming from? These are probably more important than the white smoke.