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View Full Version : open loop, closed loop, o2 sensors. etc Q's



h22ek
02-26-2008, 02:17 AM
i posted a thread the other day about my CEL codes. egr.tps.iat.and o2heated.

well i replaced the o2 today, car seems to be a bit quicker, and throttle response is better, the car almost feels lighter. well after i drove it around for a while i came back and checked the CEL codes. I know only have 1 code, 10-Intake air temp sensor. lol the other codes are gone. does that usually happen? i know that when the o2 is cold the ecu has a pre set a/f ratio that runs rich until the car is warmer. but how hot does it get before the car is in closed loop. ive also read that when in open loop due to the rich fuel content the car is a little faster. well i didn't even have an o2 until today(previous owner cut it completely out) so i had to have been in open loop the whole time right? well when i dyno'd it the other day it made 142hp, and 125tq (its a jdm h22a by the way) and the power band was super shakey and topped out at 6500rpms.so if i was in open loop why was my car so sluggish, all info and opinions are thanked in advanced.

patrick4588
02-26-2008, 02:21 AM
you got it backwards. open loop is running off the o2 sensor. closed loop is running off preset maps for wot. so without an o2 sensor, you would have been running in closed loop, but not normal closed loop. throwing a code for the o2 sensor would make you run pretty rich. id say you definitely got back some hp from fixing that!

h22ek
02-26-2008, 02:24 AM
yeah i got confused but you get what i'm saying. what do you mean , normal closed loop?

patrick4588
02-26-2008, 11:25 AM
i was just saying when you have a check engine light, there is a different set of maps the ecu goes on than when the check engine light is off. it pulls ignition timing too.

chip P.
03-01-2008, 04:36 AM
well..patrick isnt right about that. the computer ignores the o2 sensor while in open loop. and you stay there until your reach a temp of 600f.
im guessing that there were 3 wires that hooked into that o2 sensor. one of them is specifically for warming it up (o2 sensor), to make it reach closed loop quicker.

h22ek
03-03-2008, 12:04 AM
4 wire, i already fixed all my CEL thanks, there are alot of honda rumors abotu **** like this. do what i did and get an official honda manual for you car. it's freakin bible with all honda answers.

chip P.
03-03-2008, 01:26 PM
awesome, glad it worked for u
4 wire, i already fixed all my CEL thanks, there are alot of honda rumors abotu **** like this. do what i did and get an official honda manual for you car. it's freakin bible with all honda answers.