Why White smoke?

[Mikeandwendy74]

A question for ya all....i've read on here that an air leak in the fuel system could cause a truck to smoke pretty bad(white)...but theres something i'm not understanding here...why would that be an issue for causing smoke if air is neccesary for proper internal combustion? Wouldnt air in the fuel line be comparable to adding a higher flowing air filter? Kind of a silly comparison, but i think most folks here know what i'm getting at. My 1988 6.2 runs great but throws some white smoke especially on startup. I'm not losing any coolant so I dont think its a head issue. Can a tank of year old diesel cause smoking? thats what was in it when I bought the truck. I'm an electrician, I rewired all my glow plugs, gave em new connectors and can't help saying what a HUGE difference that made. The truck starts cold within 3 revolutions. I would recommend taking a very close look where your glow plug wires exit the plastic covering from your wiring harness. I found a few nicks right down to the copper. Not good. Good grounds are essential. Always scrape where ground wires connect spotless.

p.s. go rebuild that tranny cus it ain't that tough :)

[DmaxMaverick]

Air in the fuel lines causes smoke due to retarded timing. The air bubble delays the pop of the injectors. It also causes rough(er) running because all the lines won't have the same size bubble in them.

[moondoggie]

Good Day!

"Wouldnt air in the fuel line be comparable to adding a higher flowing air filter?" If you're driving along at 2000 rpm, getting 20 mpg, each injection/firing event injects 23.7

[rustyk]

Excess air would cause white smoke. This is different from the white "cold smoke" seen occasionally on startup.

As an aside, proper loving care to any internal combustion engine is, on startup, to get moving right away. Cold idling is an engine killer.

[Mikeandwendy74]

thanks for the tips, now i'll go check and see if i'm leaking anywhere. I know one or two injectors are a little leaky at the injector gasket going to have to replace those seals.