99 camry 4cyl exhaust/cat questions

[dusterbd13]

ok, im fairly certain that i have a plugged up set of cats. the cars got 230k on it, and lately it has been down on power and economy considerably. ive done all the basic checks, and what i keep coming back to is that the exhaust sound restricted. so...

my car has two cats. one right at the head bolted to the manifold, and one underneath behind the car right behind the oil pan.

ive found that other camrys had a tubular exhaust manifold that did not have the first cat, but still had the second cat.

im led to believe that the camry i have is equipped with the california emissions due to the first cat at the manifold.

my question is, can i swap over to the catless manifold, therby deleting what i believe is a plugged up cat? will the computer hate me for this?
i live in NC, whch means tyhat i do have state OBD2 inspections. so i cant throw any codes. im just looking for a way to save some coin, as the cats for this car aint cheap.

also, can i weld in a universal downstream cat, like a spun highflow? again, will the computer hate me?

lastly, sionce the exhaust on this car is getting pretty rusty and thin, i think i may replace the whole thing when i do the downstream cat. is there any higherflow options out there for reasonable money? i was thinking a system for a v6 car from the cat back, but will it fit up to a 4cyl car without a lot of mods? any cheap ricer stuff out there?

thanks, and let me know what im looking at here.

Michael

[Noblunts]

The ecm just measures with the oxygen sensors. Where are they? Around 1 cat, both? It has a threshold and if you cross it, the code pops up. You can likely get a generic high flow cat (like $60) and be ok. Otherwise you can reprogram the ECM or get a non cali ECM. Wiring may or may not be the same for 99 so I'd check the service manual.

You will have to fake out one o2 sensor if you go catless. People sell them as a "MIL eliminator" or you can modify your o2 sensor.

[dusterbd13]

ive only got two o2 sensors. one in the manifold before any cats, one after the second cat.

i would not go catless on this car. i may not like them, but i see their purpose.

care to reference me to the o2 sensor modifications for if i DO pop codes going to one cat?

[TedL]

The "O2S" on the Cali engine is actually an Air Fuel Ratio (AFR) sensor. If you're prepared to replace the whole exhaust system, including the exhaust manifold with catalyst, you could probably go to one designed for federal emission standards that would bolt in, with one potential problem. The post cat O2S is probably the same, but the AFR sensor may have a different connector and different voltage expectations...check before you leap.

[Noblunts]

http://www.mikefordmustang.com/write...liminators.php

The post cat oxygen sensor is what the ECM is concerned with anyway. You don't modify anything before the converters.

This *may* affect fuel trim, etc since it always gives a "perfect" reading.

If you've ever tried to buy bolt in exhaust parts, they are not cheap.