O2 sensors turned off in tune...bad?
06-07-2011, 02:20 PM
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O2 sensors turned off in tune...bad? I have a 2000 trans am...(mods listed below) my car ran 8.2's during the beginning of the season, He told me that he was going to put in the 2002 operating system, because it adjust for temp. better. The car now runs 8.4's now after tuning and retuning...In the tune now the front and rear O2 sensors are turned off due to one of them not switching as fast as it should. Shouild I have the tuner turn them back on? Will this help me in the 1/8th, maybe more throttle response, and better 60' times?
06-07-2011, 02:57 PM
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Sounds like you need a new tuner.
The 02s are "off" because you're in open loop. You go into open loop whenever you trigger PE (WOT), but in a normal setup the computer reverts back to closed loop for all idle/part throttle conditions. IMO there's not any reason to run that way permanently unless you're driving a racecar - tuned for every run, enormous cam, etc. When the weather changes your AFR varies wildly - especially OLSD. 2001+ OS has active temp bias tables which can help even out AFR swings over temperature (takes work to get it dialed in) vs 2000 and older softwares, but you'd be much further ahead letting the computer do its job - put it back in closed loop and tune it correctly.
The 02s are "off" because you're in open loop. You go into open loop whenever you trigger PE (WOT), but in a normal setup the computer reverts back to closed loop for all idle/part throttle conditions. IMO there's not any reason to run that way permanently unless you're driving a racecar - tuned for every run, enormous cam, etc. When the weather changes your AFR varies wildly - especially OLSD. 2001+ OS has active temp bias tables which can help even out AFR swings over temperature (takes work to get it dialed in) vs 2000 and older softwares, but you'd be much further ahead letting the computer do its job - put it back in closed loop and tune it correctly.
06-08-2011, 07:58 PM
#3
I doubt if he turned them off, what he did was set the codes for them to do not report, so it wouldn't turn of your check engine light, when they weren't active enough. A lot of guys do this when doing tunes on long tube headers
