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cat makes rattling noise on 98 accord

For the last three years the catalytic converter on my 98 accord has been bad according to my dealership. I had them check my car out after the "engine" light came on. They said it was my cat and it should be replaced, although I was 9k over the 80k warrenty so I opted to not replace it. Two days ago a loud rattling noise started to come from what appears to be the cat. I took the shield off and reattached it in hopes that the shield was loose. The rattling is inconsistant, ie. no particular rpm. I live in a state that doesn't test emissions. Would it be possible for me to replace the cat with a straight pipe? Other than the obvious law-breaking, what other risks do I run, such as what do I do with the oxygen sensor and how will it effect my car ovver the long run?

Reply to
shephard38
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The catalytic converter has no affect on engine performance and replacing it with a straight pipe would cause no harm to the engine (we won't get into proper back pressure for optimum performance here). Now the environment, that's another issue. Oh, and you might have to get used to that check engine light, cause with out a converter to tickle the rear O2S, it will keep coming on till you pull the bulb out.

Reply to
Kevin

So what do I do with the o2s? Do I unplug it or attach it to the straight pipe? And finally, doesn't the o2s work together with the injectors for proper performance?

Zeke "Women find me handsome, but they have never found me handy" Zeke

Reply to
shephard38

The rear O2S is primarily used by the computer to monitor catalytic converter performance. The front O2S is used for closed loop operation (feed back to control air/fuel ratio). If you have no CAT you just as well unplug the rear O2S. Some of the control strategy is based on CAT performance, so I guess you could say it will affect the engine when the program tries to run a CAT monitor or if it tries to make up for an always lean CAT. The effect should be minimal though. I know I have driven cars with a dead rear O2S and could not detect any engine performance problems other than failed emissions standards. Maybe just sticking the rear O2S in the pipe would keep the program happy for everything but the monitor. P.S. The CAT monitor is that part of the computer program which runs a check on the operation of the CAT by purposely causing the Air/Fuel mixture to change and looking for the proper response from the rear O2S. This only happens under certain driving conditions so it is not a constant monitoring of the CAT.

Reply to
Kevin

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