My '90 Integra is blowing white (unburned) smoke under hard acceleration. You can't see it any other time, but get hard on the gas and there's a big whitish smoke screen out the back.

Someone thought it might be worn exhaust valve guides, except I don't think there's a lot of vacuum in the exhaust ports when hard on the gas to draw it out, is there?

Is there any kind of bypass or w.h.y. that could be causing the problem? Engine is all stock, about 120k miles on it. Any ideas?

Thanks!

 

Blueish smoke = burning oil
Whiteish smoke = burning coolant

You have a leak somewhere and that smoke you see is burnt coolant.

 

Does that the smoke is only visible under hard acceleration suggest where the problem may lie? Is the first place to look a blown head gasket? Wouldn't it smoke all the time then?

Thanks again.

 

Also, just checked and there doesn't appear to be any oil in the water or water in the oil.

 

So you opened the radiator and there was no oil mixed with coolant? White means there's definately coolant in your system. If there's no mixed coolant with oil (it'll look milky), then might not be a head gasket. Do a compression test or even a leak down test would be better. Does your car over heat or run hotter than it usually does? Do you smell fumes and does it smell sweet?

Are there any mods to the car? Does the white smoke have a blueish tint to it? If it only happens during hard acceleration you might be running lean on the top end.

 

Correct, no oil in the rad, just water and anti freeze. And the oil is dirty, definitely no white.

No overheating and haven't noticed the heat being above normal. No fumes and haven't noticed a sweet smell. No mods to the car.

The smoke appears white with a bluish tinge, and LOTS of it, it's a really huge trail of smoke when I'm on it hard.

Could it be a faulty PCV valve? Update: checked the pcv valve and hosing and it seems to be working fine.

One other thing, car is standard transmission, not auto.

Thanks again.

 

Yea it can be confused sometimes but with you saying you don't smell anything and no overheating and there being a blueish tinge means you're burning oil. Not sure what can be the cause of that but i'm sure if you search on this site you'll get idea on where to start. Search under blue smoke or burning oil.

 

If you are in fact burning oil under heavy load, chances are your piston rings are fried. Run a compression and leakdown test to determine if and where the oil (or coolant) is entering the combustion chamber.

 

Just ran a compression test, first test: 180 on all, second 185 on all (I let the engine turn over a few more times on the second test). Seems pretty good.

Blew air into each cylinder at tdc and watched for bubbles or an increase in the cooling fluid level and couldn't see any.

I may buy a leak down tester. Any other things to consider before that?

The evidence so far:
-a ton of whitish or white/blueish (depending on who I ask) smoke on acceleration.
-good power
-good cylinder pressure
-no oil in the coolant or water in the oil
-car does not overheat
-no air being blown into the cooling system (using compressor)
-there seems to be oil seepage around the filler cap. At first I thought it was just excess spill, but it never seems to burn off, so I'm wondering if it's possible there's pressure under the valve cover, say from worn valve guides, that's pushing some oil out. Seal on the filler cap looks good, but always wet around there.
-Everyone agreed that the smoke hung in the air quite a while, which makes me think oil not coolant (unless anti-freeze hangs around like oil), maybe unburned oil drawn through the exhaust valve seals (would it draw it through under hard acceleration?).

Any thoughts?

Thanks!