I have a 1989 RS 305 TB with only 89,000 miles. I removed the cat converted after installing a new muffler and as soon as I cranked the car up it stated blowing white smoke. I added a can of sea foam to a full tank of gas and now it smokes like a worn out school bus, all the time not just at start up. Never a hint of smoke before. It seems to be coolant smoke but were is it coming from? It still has all the smog junk on it but all the sensors seem to be okay. I read the codes and got 12 and 23. I checked the sensor in the breather (the code 23) with a ohm meter and hair dryer and it was working. I know water circulates thur the smog stuff some how but not quite sure. I wouls greatly appreciate any help.

 

1. Are you sure it has 89K and not 189K? It is very possible on a 22 year old car. I bought mine in 94 with 126K on it, and it now has 154K on it, but after the resto people think its only 54K
2. Water does not run through any component of the emission system.
3. Upon installing a new exhaust system, even just the muffler, you may see some smoke as its buring off when new. I've never used sea foam, so I am not sure what typical results are.
4. Why did you remove the cat?
5. The smog equipment will not make the car smoke more or less.
6. Code 12 is a response code that means everything is normal and communicating. I know it has a specific meaning, but it is normal to get that code.
7. Check if coolant loss is actually occurring.
8. Before you tinker with "smog junk" make sure your areas emission laws allow you to do so.

 

Exhaust parts (mufflers, pipes, etc) have oils embedded into them that need to burn off, but it definitely should be done smoking after the first time you get the engine up to running temperature. If you have some smoking going on that won't quit, it's possible that's a condition you already had, and the function of the cat was making it less evident at the tailpipe.

 

If the cat made the smoking less evident, wouldn't it have smoked until the cat got hot prior to removing it?

 

Well, you'd think so wouldn't you? Just trying to throw ideas out there and make sense of something that doesn't make sense. Removing a cat isn't going to make an engine smoke any more than it may already be. The OP's description of white smoke right after the exhaust work would be normal. "now it smokes like a worn out school bus, all the time not just at start up" needs a little more explanation. Has the car been given a good road drive to fully "break in" the exhaust?

 

Yes, it doesn't make sense that an exhaust mod would cause, or uncover a previous problem. It is possible that the engine was on the verge of blowing a head gasket, and it just happened.

I would try running the seafoam out, and filling up with fresh gas. I still have never heard of seafoam causing noticeable smoking.

 

I would assume he already ran that tank of gas out?... it usually wont stop smoking untill all the sea foam is burned off..

 

Sorry for the late response. Im gonna try to remember all the questions. We do not have emission laws were I live (Thank God) I removed the cat to get more sound/flow, The car does have 89,000 miles I'm the second owner and bought it from a freind who bought it new, Im 95% sure it does not have a blown head gasket, there is no water in the oil and the coolant leave is not dropping fast enough, Its not the oil in the pipes/muffler it would have already burned off by now, I have not ran all the sea foam out yet and have used sea foam many many times before and always had good results, when the car is running the tail pipes are sooking wet and the rear bumper fogs up like steam will do. Its got to be a sensor, Im just not sure which one. My brother has a Firebird and his done some what the samething just not as bad but stopped after all the smog junk was removed. I wanted to keep that stuff on since the car had low miles and if I wanted to sell it to some one in a emission state all I would have to do is put the converter back on. Sorry if I missed something. Thanks for the questions!

 

Thanks for the questions.. That's good! I was hoping to give answers but I'm stumped. When you discover what is causing continuous smoke, please don't forget to post it.

 

Im going to do a compession check tomorrow to clear up that 5% doubt on the head gasket. If that checks okay I'm just going to remove the smog stuff. The car just ran to good and still does to be something that big. The plugs should tell me if there is a major problem and the are a clean as a pin. But you never know. Thanks guys, I will let you know what I find.