Lm2 blue smoke on cold start

[kervin Morales]

Hi guys new to posting on forums. I have a 21 Sierra with the 3.0 Duramax in it. Has about 6k miles on it. It has been pretty cold here in Colorado noticed today after sitting for 2 days when I started the truck it started a bit rough and smoked blue/gray for about 5-10 seconds. Has anyone else noticed this? I don’t know if this is the first time but this is the first time I noticed it, any input would be great!

[redwngr]

From tailpipes or somewhere else? 

 

 

[kervin Morales]

Yes from tailpipes 

[BlancoSilverado]

Did you remote start of in the truck start? Does the truck have a delay system to heat the glow plugs?

[kervin Morales]

I did remote start it I don’t know if it’ll wait for that when it’s remote started.

[eckseleven]

It will use glow plugs when remote starting if conditions require them.

[kervin Morales]

Are you sure? Because last time it was below freezing and remote start didn’t take any longer 

[eckseleven]

How low below freezing? It needs to be quite cold before they come on.

[kervin Morales]

It was -5 to -10 

[kervin Morales]

Fahrenheit 

[eckseleven]

Ok. I'll admit that I haven't stood outside mine and remote started it with it that cold, but I don't see why they would have designed the glow plugs to not operate when remote starting. Pretty sure I read somewhere they are used regardless.

 

When I was inside mine and started it when it was about 5 degrees Fahrenheit, it very briefly gave the message about startup being delayed, maybe a second or two. If you get any more cold days, hop in a start it to see if it behaves any differently.

[kervin Morales]

Yea I will try it next time for sure! The real problem to me was the blue smoke 

[eckseleven]

Yeah I'm not sure about that part. Do you have high idle warm up enabled? I haven't payed attention to the color of the exhaust but it does smell kind of sweet during that phase.

[kervin Morales]

Yea I have that enabled I might try to duplicate this situation and see if it happens again then try it one more time with high idle disabled and see if there’s any difference.

[redwngr]

Shouldn't be blue tailpipe smoke no matter what the settings are.

 

Reason I asked about tailpipes is there have been a few trucks with exhaust leaks in other locations -- and known solutions for those.