I replaced my o2 sensor in my 90 rex si b/c it smelled rich all the time and plus I just reinstalled the factory cat converter and I don't want to ruin it b/c I was burning too much or too little gas.

I replaced the 02 sensor with a bosch one (not sure if its good or not) and the rich exhaust smells seems to have been eliminated.

I'm hoping that by replacing the o2 sensor on my car that my gas mileage will also improve.

Before sensor replacement my car would get about 450-475 before it was bone dry.

When I hit the halfway marker on my gas gauge I would have traveled about 250-260 km's.

Right now with the new o2 sensor I'm at 230km's and my gauge is still just a little above the halfway mark but I'm not driving the car as light as I normally do b/c I've gained some extra power from the sensor replacment.

what typical figures are you guys getting?
Engine: d16a6 with AEM CAI and dc sports 4-2-1 header and dynomax ultraflow muffler and factory cat.

 

i get approx 30-35 MPG in a '91 CRX SI w/ very similar setup. I don't drive like an ole lady either. As you know already, driving style has a huge effect on fuel efficiency.

 

its weird... after replacing my o2 sensor the car seems to have more power and is more responsive and doesn't smell as rich but gas mileage I think is exactly the same.

Do o2 sensors actually lose efficiency/effectiveness over time?

Thanks

 

i have a sohc zc and i only get 200 miles to the tank. i think ineed to change my o2 censor. i only have some chit intake and greddy exhuast.. any suggestions

 

probably a good tune up, timing check, pcv valve as well as 02 sensor replacement is probably going to help a lot.

My reasoning for replacing my 02 sensor was the fact that it occasionally bogs a bit and then the a/f ratio meter reads slightly rich and never leans out completely. Despite autometer's inaccuracy and the fact that the stock 02 sensor is narrowband it nonetheless told me I was a bit rich. After replacing the 02 sensor my car doesn't smell rich anymore and it runs better and the gas mileage has improved a little.