02 LB7 White smoke and a knock... ??

[gr8shot]

I think white smoke at idle is often times uncombusted fuel due to low cylinder and combustion temperatures. People who idle lots in their trucks ie. jobsites where the truck idles all day, will see white smoke after idling for a while. I think its cause the egt's get so low that all the fuel isn't getting burnt. Make sense? I know black smoke is also unburnt fuel, but thats usually when its getting good hot combustion and there's just too much fuel to get burnt completley. Not sure if thats what it is in your case, but as long as your not misteriously losing coolant then thats probably it.

The way to tell is if it will still do it right after you stop from a good highway jaunt, or towing. It shouldn't smoke white then, just when its cold or has idled for a long time. Hope that helps.

[duaner]

By the way Turbo dog... I got a carfax on the truck when I bought it... it didn't say anything about injector issues. I even called the dealer who sold the truck the first time and asked them and they said nothing had been done besides routine maintenance.

Hmm... maybe the ones that knock are the only ones that the injectors DONT fail in... yeah yeah that's it... lol

-duane

[duaner]

gr9shot,

I think what you are saying makes good sense. I was noticing just the other day after I ran the truck pretty hard it took about 6 or minutes before any white smoke started coming out. Before that the exhaust was as clear as could be... you could just see heat waves through it is all.

Will a big custom 4" exhaust cause lower egt's i take it? If that's the case, then I am feeling even better yet.

thanks guys
-duane

[TurboDog]

Duane,

I think you're getting some good advice on the smoke issue. When my injector did go out, I first noticed it by seeing some puffs of black smoke while running down the road. When it completely failed, it was due to injector stuck open dumping fuel into the cylinder (and spewing clouds of black smoke).