tuning out rear o2's
 

ok so i got my front o2 extensions in place, and it'll be awhile before i can get my rear o2's tuned out. will the car run like shit until then?

no...will have an SES light tho..

how much is it to have them tuned out usually?

don't know for sure... but after looking around on these threads i would say in the neighborhood of $75. just depends where you go and what state you're in. like here in nc we're emission controlled so it might cost me "a little extra"...

I wouldnt pay more than $100 to have it done, because youre basically just paying for a license of the tuning software. It literally takes less than 5 minutes to turn the codes off and reflash the car.

rapid gave me a $75 quote

Depending on the year of the car its free.

We were able to tune out the EGR & AIR on my 98. 99+ Needs a license.

you can get O2 simulators... for $35 a piece.

lol where at? they are like 100 for two plus shipping everywhere I've seen

O2 sims are illeagal and most places have stopped selling them. Caspers (the maker) has stopped making them after a HUGE fine from the gov't. The only place I've seen them is ebay and used.

your car will run rich

The car should run fine, it will just have a check engine light.

Rear O2's do not affect your A/F mixture.

Yes, yes they do. Rears are used to check the short term trims. Your car will bounce back and forth between rich and lean and generally feel like shit, and also have 3/4 the power you're used to.

not having a catalytic converter is illegal too, which is why casper was fined.


so why did i run 2/10 quicker down the quarter after i installed long tubes and COMPLETLY REMOVED (without tuning them out) the rear 02 sensors? front 02's moniter a/f, rear 02's turn on the ses light when the cats are damaged or removd.

When you go WOT all of the OBDII stuff is negated. The 02s do not do anything. Yes, you are right about what they do but the computer uses the rear signal not only for telling if the cats are good or not but to adjust the mixture to allow for the best "burn". I should have been more specific in my last post, sorry. Now, if you unplug the front 02's you will set a hidden code, and you will just run open loop forever, basically what the car does when its warming up.

No, no they don't. The rear O2's have no affect whatsoever on the car's A/F mixture, which is why they are able to be tuned or replaced with sims. Their only purpose is to monitor the cats.

QFT, the only function of the rear O2s is to monitor CAT performance.

when i did my long tubes my afr's were all ****ed up then when i got them tuneed out my car ran fine and the guy who tuned them out said the rear o2's should not have no affect on my afr readings

WTF?! You sir...are dead WRONG! :D