Finally got my car running again and the exhaust seems to be blowing out white smoke mostly at idle.

I know this sounds like this has already been covered but my car is throwing a code, some kind of p240 i think and it was a catalytic converter failure

I was told that a bad converter will decrease your mileage (mileage is not good at all) and performance but i was also told that it isn't causing the white, oil smelling exhaust fumes to come out of my exhaust.

Any suggestions? or advice?

White smoke is coolant/water. I'd be looking at a possible head gasket. Do a compression test and see if you have good compression on all cylinders. Odds are, probably not, and that will give you crappy gas milage and poor performance also. Keep up posted.

Originally posted by kvoriley27
Finally got my car running again and the exhaust seems to be blowing out white smoke mostly at idle. I know this sounds like this has already been covered but my car is throwing a code, some kind of p240 i think and it was a catalytic converter failure I was told that a bad converter will decrease your mileage (mileage is not good at all) and performance but i was also told that it isn't causing the white, oil smelling exhaust fumes to come out of my exhaust. Any suggestions? or advice?

ive seen cats do some crazy ass things.. idle it at night and look under the car if its clogged its gonna be glowing a vibrant cherry red. quick easy test

Okay so ill wait until tonight and check the cat. And what do u mean by crazy things lol.

Thats what I hear about the white smoke but it smells like oil and mostly does it at idle.

Ill borrow my dads compression tester and let u know as soon as i find out.

Also, should i just go ahead and replace the cat now or wait?

White smoke isn't an indicator of a bad cat, it's an indicator of something burning that isn't supposed to be burning. Usually a bad cat will either clog and make the car perform like crap, smell like rotten eggs, or get insanely hot and glow. I've never seen one smoke.

If the car is smoking at idle the things to look for would be a leaking headgasket or bad valve stem seals. White smoke is usually indicative of burning coolant, but burning oil can be very similar as the bluish tone of the smoke is hard to see unless it's in large quantities.

Originally posted by RoninEclipse2G
White smoke isn't an indicator of a bad cat, it's an indicator of something burning that isn't supposed to be burning. Usually a bad cat will either clog and make the car perform like crap, smell like rotten eggs, or get insanely hot and glow. I've never seen one smoke. If the car is smoking at idle the things to look for would be a leaking headgasket or bad valve stem seals. White smoke is usually indicative of burning coolant, but burning oil can be very similar as the bluish tone of the smoke is hard to see unless it's in large quantities.

Ya im gooing to look at it better because there isnt enough smoke to be able to tell what it is.

It also has been studdering when i accelerate at certain RPM's

I've seen a cat on a friends z24 caviler clog and combust(lack of a better term). When it lit off it took out the a/f sensor. This caused the car to
Dump fuel into the already glowing catalyst making greyish smoke.

Is this your problem
99% chance not

But my point is anything is possible and never rule out the "impossible"

Just my .02

Dammnnnn thats crazy yeah my cat was not glowing red when i checked but i didnt drive for too long

Well i noticed a hanger from the exhaust was jacked up then on my way home the gasket for the cat converter blew and it sounded like shit.

Took off the converter and geuss what? It has been gutted so I do not even have a converter that could be throwing some codes im geussing?

But we have concluded I have bad valve seals I should be fixing this soon.