No cats and o2 sensor porblem

[photoguy30523]

ok if i have no cats my o2 sensor wont work right. how do i fix this problem?

[Starmavin]

If your car is 95 and older you have only one up stream o2, meaning your car's computer won't know if it's there or not. If you have 2 o2 sensors (one before and one after) the computer will know if it's there because it compares the two sensors output and will kick a MIL. After a while with the 2 o2 sensor system the o2 and/or cat will kick up the dreaded P0420 code that just about every tech hates to deal with.

[fastshivy]

So your car is a 1989? If this is the case there is only one O2 sensor. It is upstream and and is not affected by the cat. Google O2 simulators if you want more in depth info....... Meeeeeeeeeowwwwww

[Starmavin]

I ran into an 89 that had 2 o2 sensors. The second turned out to be an aftermarket add on the previous owner installed for some reason.