First off let me announce, im new to this site/forum! An im a big fan of the 4th gen f bodys as this is my 3rd lt1 camaro an 5th f body car.

I got a 94 lt1 camaro, 135k miles. Auto. I drive the car maybe Once a week. An only maybe 15 miles. Occasionally ill drive it to my parents place witch is about 40 miles one way. (Let her stretch her legs) anyway I got a sweet deal on it (hopfully) so I couldnt pass it up. When I bought the car it ran weird. As if it wasnt getting enough fuel or it was being choked out...anything more then a hair on the throttle an it would fall on its face. I had no other option to get it home other then to drive it how it was an pray I would make it home before I did any real harm to the motor. The drive was awful, i couldnt get the car up past 50mph an at times, it would drop to 35mph an there was nothing i could do beside feather the peddle enough to slowly build speed back up. Come to find out it had a clogged cat. I cut the cat off an replaced it with a peice of pipe. Fired the car up an boy did she scream then. An to this day runs very good an has very good throttle response. And has very good power still. Same as my other lt1s I had. But regardless if the motor is hot or cold, when I rev it up to even 2500-3000rpms it blows out white smoke. An really blows out thick white smoke when I rev it up to 5500-6k rpms. The car runs damn good an acts as if nothings wrong with it. I didnt think nothing of it, figuring it was just all that stuff in the manifolds an exhaust that built up from havibg a clogged cat. Figured after I drove it a couple hand ful of times an maybe took it out an ran it a little hard to help clean her pipes it would stop smoking. Well 3 months has went by an it still smokes way more then what im comfortable with. Id like to think I know quite abit about cars to sorta determine what I may or may have not done to the car. Im thinking I or previous owner fried the rings. Or it needs valve seals. But im kinda iffy on the valve seals bc as I said, it smokes hot or cold. I want to figur this out fast as to summer is coming an i dont want to spend all summer working on it. Thats what ill do next winter lol. Any insight will be very appreciated!

 

Are you low on coolant?

 

agree with above comment. Thick white smoke sounds like coolant.

 

No, thick white STEAM is water. Thick white SMOKE is either oil or its dumping a potload of fuel into the mix and the smoke is the unburned fuel. OP - what does the smoke smell like? That'll tell you straight-away what it is. Coolant steam is very sweet smelling, and will dissipate quickly in the air. Fuel smoke smells like gas. Oil smoke has a blue tint and smells sour. Smoke will not dissipate like steam. Instead, it thins out in the air and eventually disappears. If the air is dry enough, steam disappears within moments of hitting the air.

You already stated your cats were bad. Melting cats doesn't happen due to age - it happens because something melted them. Usually, its a result of too much fuel being pushed into them and then the cats burn it and melt in the process. Find the reason they melted in the first place and I bet that will also address your running issues

 

Ill make a video today of it. An throw it on youtube. Im sure that will help yalls opinion. An ill be sure to check the water in it. Ive checked the oil an the oil seems to be right on point. (Less that 100 miles on new oil changed) I guess my next question is, is it possible from where I drove it almost 50 miles home with a clogged cat, I could have done some damage some where? Id like to thing that couldnt have been good for the heads..all that back pressure...

 

Someone will undoubtedly correct me if I am wrong, but I don't think the heads would be harmed by running with melted cats. They can handle a lot more pressure than a clogged exhaust can generate. If it was plugged solid, the car would just stop running because it couldn't get rid of the exhaust it was creating.

Figure out if it is smoke or steam. That's where your problem is. The melted converter is a symptom of your issue. Its not the cause.

 

What do you guys think would cause a cat to clog up?

 

More than likely - too much fuel. A bad misfire will also do it (introducing too much fuel into the cat) but you'd know if that was the case. Get the ALDL cable and Scan9495 and post the scan. The o2's will tell you a lot about what is going on.

 

BLUE smoke is oil, BLACK smoke is fuel, WHITE smoke is coolant

 

The most common issue I've seen is an exhaust leak. The rear exhaust manifold bolt seem to back out or break, that ends up sucking air in causing a false lean condition. The PCM then adds fuel.

Did you open the rad cap and check coolant level?

 

NO, White smoke is RUBBER!

 

lol, wait I thought burnouts were PINK!

 

https://m.youtube.com/watch?v=bbj4wWozaik


This is a cold start. An ive checked the coolant today after droving it home from work. (About a 20 min drive home small highway) the coolant is still full. I checked my oil, oil is low but still looks clean. (Not even 100 miles on the oil change) I put a rag over one tail pipe an then smelled it, sorta just smells like exhaust... ive noticed today after its warmed up, it dont do it AS bad but still smokes when reving it up. Also, today when reving it up while it was warm, around 5600-5900 is pops. Like a cough...or maybe like spitting back up thru the motor....

 

After watching your video, my opinion is that the stuff at the start is steam. You can see the water puddling on the ground under your pass-side outlet at the end of the vid. At 1:50, when you rev it, the steam almost immediately vanishes. You can watch the steam disappear as it floats past the "camaro" on the back of your car. At 2:10, when you really rev it, it shifts to a combination of smoke and steam, and stays in that state until the video cuts off. And revving a cold engine like that is a bad idea.

I'd do a compression test, and a leakdown test, and then maybe buy/borrow one of these. They work pretty well. I've had one in my box for years and used it exactly twice. Worth every penny when I needed it. Pull a scan and see what the O2's are up to - they'll tell you a lot as well

We can agree to disagree on this point, then. When coolant is introduced to the combustion chamber, since it is mostly water, it turns to steam. Since people commonly refer to this steam as smoke, your mechanic won't correct you, but I will. Rest assured - its STEAM and easily identified by either the sweet smell, or the way it dissipates in the air. Since its steam. Not smoke. White smoke is unburned fuel being ignited in the exhaust - beyond the point of making black smoke from an overly rich mix (or if you have a diesel - its dumping in diesel). Note - if this were happening on a GAS car, the fumes would burn your eyes. Its not common, but it does happen. White/blue smoke is oil. Black smoke is a sign of a too-rich mix

 

Also, on another note, when I start it cold it seems to idle perfect. I drive it for a little while or just let it get to running temp an it idles at 1400rpms while its in park. Put it in drive an the idle drops to about 800-900?!...my other auto lt1 I had didnt idle this high. While it was in drive it idled around 600-700 an park maybe 1100rpms.