02 sensor question

Which one is more important? After the cat or before? Looking to replace some exhaust parts and they are on the list along with a new muffler and tailpipe. The cat is pretty much junk so I will just hollow it out for now so it is not clogging up the exhaust. TIA

Kim

85xjwoody said:

Which one is more important? After the cat or before? Looking to replace some exhaust parts and they are on the list along with a new muffler and tailpipe. The cat is pretty much junk so I will just hollow it out for now so it is not clogging up the exhaust. TIA

Click to expand...

Both are equally important. The one before the cat measures raw exhaust gasses; the one after the 'cleaned' gasses from the cat. One's compared against the other to adjust mixture, timing, etc. to improve the effectiveness of the cat.

I think that the after cat sensor is the one giving me the problems. The check engine light comes on alot and I have to dissconnect the battery to reset the computer.
My cat is bad but I don't have the $120.00 to get a decent one so I am hoping that when I hollow it out and replace the after cat sensor, muffler, and tailpipe it will be ok for our trip at Winterfest.

Kim

85xjwoody said:

I think that the after cat sensor is the one giving me the problems. The check engine light comes on alot and I have to dissconnect the battery to reset the computer.

Click to expand...

Hard to say without for sure measuring the voltages at the sensors, but yeah, it's definitely possible that it's only one that's having issues.

My cat is bad but I don't have the $120.00 to get a decent one so I am hoping that when I hollow it out and replace the after cat sensor, muffler, and tailpipe it will be ok for our trip at Winterfest.

Click to expand...

Quite probably, but my rule of thumb is that I replace both sensors at once - it's easier to know when they were both last done that way, and could potentially save having to replace the cat a second time.