joshcivic00

the shop i took my car too put two new o2 sensors on my civic because i was having turbo problems(as many know).anyway my stock cat and cat o2 senor was fried. he put the stock o2 sensor in the catco highflo cat and strapped the new one outside the cat.could this cause problems and is it better to leave the the o2 sensor in the cat(although its high flo).

Simple

depends on which sensor he strapped outside the cat.... the primary o2 sensor usually is located before the cat and it senses temperature in which it bases the fuel/air mixture on, and adjusts fuel/air (corrisponding with all the other sensors that pertain to the PGM-FI system) the secondary o2 sensor (usually placed inside the cat, but in this case, all your car has is a pipe, so the primary is placed in what it thinks is the header before the cat) anyways....all the secondary o2 does is sense heat inside the cat... to tell you if you're cat is doing its job buring the access amount of fuel, or if its getting plugged up...

technically, the 1st one is doing its job.... second one isnt... they both sense heat and adjust the air/fuel mixture... dont know what to tell you, but i hope it gives you a better understanding of what does what...

based on that.... use your own judgement