0235SS93

iTrader: (1)

When my h/c/i lq4 is idling, there is a whitish/gray smoke coming from the exhaust tips with the idle exhaust pulses. It also smells a tad rich. The truck does have lt's, no cats, x-pipe with magnapack straight-through mufflers. I just finished up a retune and the idle afr bounces between 14.3-14.8 as measured by an Innovate LM-1 wideband. I run 92 octane gas. I have a roll pan and dual outlet rear exit tips. There are also little black specks all over my tailgate after a few days of driving or alot of WOT pulls. My buddy has me worried that this is oil coming from my exhaust!? Is this normal for a cammed truck wirh no cats? Or should I start checking things?

00Silv4.8

iTrader: (10)

valve guides? blow by?

0235SS93

iTrader: (1)

I wouldnt think it would be either of those, as the short block only has roughly 45k miles on it and the heads have even less...Neither the engine block, nor the heads have been touched other than the valve spring swap and being bolted together.

zero2sixT

iTrader: (4)

From my experience, blue smoke is oil burning. White smoke might be coolant. You notice any loss of power? Check your plugs, see what they look like. Are any of your fluid levels dropping? Are you seeing the white smoke when the engine is warmed up?

Only black specs I get after some WOT pulls is rubber.

Suburbazine

It could simply be condensation blowing out, or it could be coolant. You can always check the tank to see if you're losing coolant, or use test dye. If it was oil I'd imagine that the cloud would hang around a little bit after it comes out the tailpipe, water would not.

Mine blows condensation everywhere, so it can be a normal thing. Condensed water will also carry carbon deposits, so black buildup on the bumper isn't necessarily oil. (and oil stays oily, too)

0235SS93

iTrader: (1)

Yea, i took Automotive Tech my junior and senior year in high school. One of the first things we learned is what different smoke colors/smells meant. And this is congusing me cause it isn't blue like oil, it doesnt smell funny, my truck is running stronger than ever, and all my fluid levels are fine. Its almost like the smoke/steam you get when you start your truck on a cold morning, but it does it ANYtime the truck is idling. Also, the exhaust doesnt smell funny, just smells like a truck with no cats. My first thought was oil, due to the blackish spots on the tailgate, but it the smoke isnt blue and it only does it at idle. Rev it up or drive down the road, no smoke at all....Also, its not alot of smoke, just thin lil puffs that are barely visible on the light of my taillights/license plate light.

0235SS93

iTrader: (1)

Thank you Suburbazine! I was thinking it was condensation too since my exhaust has no drains and my tips are slightly angled up. Its a really thin, whispy cloud like steam. And when my truck sits idling for a few min, there's usually a few drops of water on the ground right under each tip. But i would think that if it was indeed just water in the exhaust that it would go away fairly quick.

Suburbazine

The engine generates fairly large quantities of water as a byproduct of combustion. If your exhaust can develop hot and cold spots the water will condense in the cold(er) spots and then steam on the hot ones. When warmed up mine will make a big wet spot on the ground simply from water blowing out the turndown. It's even more pronounced when I run E85.

0235SS93

iTrader: (1)

Jsyk, my passenger side valve cover pvc is vented to the intake tube and the driver side is vented to the intake manifold. Could it just be small amounts of oil from the pcv system? I'm going to do compression and leak down test tomorrow just for curiosity sake.

Suburbazine

It could be oil from the PCV, but oil is normal in the intake and PCV system. Many folks on here run catch-cans to keep the oil out of the intake.

The intake tube line is your influx to the crankcase, the manifold is your suction and where you will find most of your oil.