on the cat, there is the exhaust in, exhaust out like most cats. on the 89 tercel (carbureted) there is a third outlet, a 'l' shaped, three inch long, 1/2 inch diameter pipe that just spews exhaust... what is it for?????
It's an 'oxygen tube' or some such...if you trace it I think it goes back to the intake.
I had on on an '83. Air tube, I think. Since my '83 was safety only (inspection) I think my mechanic friend removed it...I can't remember.
"tercelhell3" wrote in news: snipped-for-privacy@localhost.talkaboutautos.com:
It's called a "pollution pipe".
It's there to feed fresh air (from the air cleaner) to the second half of the catalytic converter. The first half tends to consume all the oxygen from the engine, leaving little for the second half to use in its operation.
If yours is rusted off, and it appears it has, you have a choice:
1) If your area has no emissions test, just plug it up with something, a large bolt will do with exhaust gum coating it. 2) If your area has an emissions test, you'll fail with that leak, and you'll have to fix it properly by reconnecting it to the air cleaner.
On my '87 Corolla SR5 (with the 4A-C engine), I have a pipe matching that description (except maybe the length) that connects to a hose that goes forward to the Air Suction (AS) valve mounted on the side of the engine. My Haynes manual (combined with my logic) says its purpose is to let air into the exhaust tract at the upstream end of the catalytic converter when there is a partial vacuum condition there, for more complete burning of exhaust hydrocarbons in the catalytic process. In other words, its lets air into the cat. when there's not enough, so that the cat. does its job more completely. There should be an AS valve attached to this small pipe; without one, it seems to me it is spewing exhaust straight off the manifold. I would think this would make your car noisier as well, because that pipe is an open exhaust outlet with no muffler. And there is a risk that exhaust collecting under the car will enter the passenger compartment, especially if you have any body rust. If it were my car, I wouldn't drive it as is in city traffic without the windows open. You could either connect the open AS pipe to the (an) AS valve or just cap the pipe, though I'm not sure how just capping it would affect your emissions legality and inspection.
Stephen
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