Can't Get Enough
Join Date: Sep 1999
Location: Cotopaxi, Colorado
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Re: Effects of gutted catalytic in TJ
Youir '97 TJ is ODB11 compliant. Which means you have 2 O2 sensors. One upstream, ahead of the cat, and one downstream, behind the cat. The upstream O2 is used primeraly for fuel trims, and the downstream O2 is used for performance testing the cat. Your pcm can recognise that your catalyst is inop. This is why the check ingine light is on. Catalyst performance. The only way to turn off the light is to replace the cat and clear the codes. As far as damage to the system, it can wear out your check engine light for being on all the time. It shouldn't hurt your O2 sensors at all, just the anoying light.
FYI, The O2 sensor is way down the bottom of the food chain as far as mixtures are concerned. They are used for fuel trims to correct long term adaptives, then multiplied by load, coolant temp, throttle position, etc.