Smoke from exhaust.

[Nizmo]

Here is the run down. Last week my car overheated and busted the coolant bypass line.

Fixed it, the car started smoking under hard acceleration, between 4k-redline. Now today i noticed light smoke coming out of the muffle at idle, cold and warm. I am unable to determine the exact color of the smoke, it is either white or gray. Ive checked the coolant, hasnt gone low, no oil present. Checked the oil, no coolant present. Ive checked all the plugs and they are in perfect condition.

I dont know if it helps but... I have 2.5in exhaust w/ gutted cat and res. delete. The outside temperature drops to 30f at the lowest and 55f highest. I drive the car during the lowest and highest temps of the day.

I believe it's the head gasket or a piston seal, but am uncertain of the true cause, any advise or opinions? Thanks.

[visualpoet]

Smell it. Sweet is coolant, acrid is oil. It doesn't take much to produce some smoke either way, you may not have burned enough of whatever off to notice a drop yet. What color is the smoke under hard acceleration?
You said "at idle, cold and warm", do you mean the car, or the ambient temp? If you've driven around for a while, does it stop?

['93CB7Ex]

compression or leak down will tell you what it is.

[Apache]

X2....... Good advice!!!!!

[JDM_CB7_TX]

all of the above... What is the coloration of said smoke?

[Nizmo]

+

It's either light gray or white... its hard to tell(dont have anyone to rev it up for me). I just got home now and did not see any smoke, even with the pedal pressed to about 3k rpm. I do how ever get constant smoke under WOT past 4k rpm. So it seems once the motor is warmed up and run for a bit it doesnt smoke at idle or any other rpm until 4k+.

I also noticed just now after holding the rpm at 3k for a min. or so the car almost wanted to die, it would drop to like 300rpm and bounce around a bit then recover itself. I dont believe it smells sweet, just smells like normal exhaust. So for now i will perform a leak down when i get time, guess I will have to daily drive the Z for a bit.

Also the car has burned oil since I bought it... about 1/10th a quart per 8 or so days.

[Nizmo]

Found the problem, it turns out the previous owner put a different honda dipstick in... what a dipstick right? Picked up the proper dipstick today and corrected the oil level. So i have been overfilling the car, hence the smoke and what I thought was a problem with the car burning oil. I'm glad to see thats it, no more smoke. I just hope I didnt blow any seals while it was overfilled.

[deevergote]

How overfilled was it? Do you change your own oil?



Just to comment on your cat... why do you have a gutted cat? You realize that actually COSTS you power, right? A gutted cat provides far more restriction than a functional one.

[Xsjado]

theres a lot of cb owners running these.
I'v heard the fine is between 2 too over 10,000 dollars.
and a 25,000 dollar fine to the workshop who did it.

makes a complete alloy or even ti exhaust look cheap.

[deevergote]

You don't need a shop to gut a cat... just a hammer.

But it sounds and smells terrible, pollutes the environment, it is illegal... and provides a significant amount of turbulence, which creates a serious restriction. Gutting your cat is one of the dumbest things you can possibly do.

[tgdrums1990]

You don't need a shop to gut a cat... just a hammer.

But it sounds and smells terrible, pollutes the environment, it is illegal... and provides a significant amount of turbulence, which creates a serious restriction. Gutting your cat is one of the dumbest things you can possibly do.

Damn deev, why you gonna break my heart, ive been rocking a gutted cat for good reason when i first did my 421 header with full cat back system, my cat was toast and didnt have one so i was like maybe its a sign to gut the cat and gain some ponys... But now i feel sheepish... Cat here i come... Thx for the heads up...

[deevergote]

Always glad to educate, save the environment, and help keep the lawmakers from cracking down even harder on us tuners!

People should read up more on exhaust theory, and understand what goes into making power. Exhaust velocity is important. Everyone knows that restrictions will reduce power, but people don't realize that anything that causes turbulence in the exhaust flow will decrease flow velocity. All the exhaust gas swirling around in that wider chamber of a gutted cat will be a HUGE restriction.

[Nizmo]

It's temperary for me, when i was installing my exhaust I discovered the cat was clogged(inlet red hot/outlet cold) so we just hammered it out. You cant get cats out of the junkyard anymore so Im just waiting to buy a new oem or aftermarket one. I also dont have any laws in my area concerning emissions. I try to be a "green" as possible but my funds are very limited.

The car turned out to be about half a quart over, all I know is it has not smoked since corrected. I do my own oil changes but this was my first since owning the CB. I bought it from a friend at work, and he did the oil two days prior to me buying the vehicle(even asked which oil and filter I wanted).

[93F22A6]

It's more than just tuners on the cats, it's not such a big issues in the 4x4 world but it could come up. Land is the biggest. Pressure test it and see what your get, if it's smoking I am sure the plugs will read something. If it's oil you'll smell it, can't mistake that one.