With our cars running 20+ years old now and most of us over the 100k miles mark, I wanted to see where the knowledgeable NAM3 people stand on this and their experiences.
I've had a code pop up about 3 times for bank 1 sensor 1 (precat) O2 sensor over the course of 20k miles, saying that it's slow response, but it clears itself after a few starts and I have no pending/active codes. I want to say my mileage has been down, currently at 113k miles and it seems to have dropped from about 25mpg from 30k-80k miles, and around 80k miles started getting 21-22mpg average. Hasn't changed much since. When I search plenty of threads, my MPG is actually pretty normal at 21-22 and the 25mpg was actually on the higher side.
So for your thoughts...
1) Necessity of replacing pre-cat O2 sensors at this mileage (as preventative, since codes are few/far apart for now)
2) Anybody used the standard Bosch narrow band O2 sensor and crimped the BMW specific connectors in place? Someone said these sensors are tuned with the wire resistance factored in, so don't do this. RockAuto has a decent price + 10% instant rebate on the BMW specific Bosch ones right now...runs about $150 total for the pair, so not really worth trying to save $80-100 given the work of getting the O2 sensors replaced.
Lastly, DIY for pre-cat O2? Any tips/tricks? Special crow-foot wrench that makes it easier vs. a general 22mm one?
Thanks!!
I've had a code pop up about 3 times for bank 1 sensor 1 (precat) O2 sensor over the course of 20k miles, saying that it's slow response, but it clears itself after a few starts and I have no pending/active codes. I want to say my mileage has been down, currently at 113k miles and it seems to have dropped from about 25mpg from 30k-80k miles, and around 80k miles started getting 21-22mpg average. Hasn't changed much since. When I search plenty of threads, my MPG is actually pretty normal at 21-22 and the 25mpg was actually on the higher side.
So for your thoughts...
1) Necessity of replacing pre-cat O2 sensors at this mileage (as preventative, since codes are few/far apart for now)
2) Anybody used the standard Bosch narrow band O2 sensor and crimped the BMW specific connectors in place? Someone said these sensors are tuned with the wire resistance factored in, so don't do this. RockAuto has a decent price + 10% instant rebate on the BMW specific Bosch ones right now...runs about $150 total for the pair, so not really worth trying to save $80-100 given the work of getting the O2 sensors replaced.
Lastly, DIY for pre-cat O2? Any tips/tricks? Special crow-foot wrench that makes it easier vs. a general 22mm one?
Thanks!!