O2 Sensor location question
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From: Manama Bahrain
O2 Sensor location question
On long tube headers where should the o2's be? If you look in the pics I posted below youll notice it's located high. Shouldnt it be at the bottom where all the tubes come together?
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From: Manama Bahrain
Originally Posted by RRT vette
I would mount a boss/bung in each pipe the header bolts on to. I would also use heated O2 sensors if you don't have them already. I like the black headers.
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From: The Motor City
Originally Posted by honda hunter
These are already on my car. Ive been having issues with the car running like crap in closed loop. Today I noticed that my O2 sensors were mounted in the hole shown above. I think this is the reason my car has been running so horrible. I'm hoping I can get a shop tonight to relocate the bungs lower where all the collectors meet up.
(02 being comtaminated from silicones (on build up)or loaded up will do similar things)
It is possible that that location willl have an effect on the tune. On mine when I first set it up using no.8 for the 02 showed a rich effect, relocating it to the collecter leaned it quite a bit(w/no changes in the tune), which then required some new VE calculations. The collecter location will be monitoring the whole bank. My theory is that located on #8, and being at the back of the intake, less air is being "seen" so calculations by the ecm are different. (mine is a MAP stradegy so the tune is effected more easily from mods).
Last edited by mseven; Oct 25, 2006 at 12:47 PM.
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From: Manama Bahrain
Originally Posted by mseven
I would first start scanning and see what is going on (BLM ec.)
(02 being comtaminated from silicones (on build up)or loaded up will do similar things)
It is possible that that location willl have an effect on the tune. On mine when I first set it up using no.8 for the 02 showed a rich effect, relocating it to the collecter leaned it quite a bit(w/no changes in the tune), which then required some new VE calculations. The collecter location will be monitoring the whole bank. My theory is that located on #8, and being at the back of the intake, less air is being "seen" so calculations by the ecm are different. (mine is a MAP stradegy so the tune is effected more easily from mods).
(02 being comtaminated from silicones (on build up)or loaded up will do similar things)
It is possible that that location willl have an effect on the tune. On mine when I first set it up using no.8 for the 02 showed a rich effect, relocating it to the collecter leaned it quite a bit(w/no changes in the tune), which then required some new VE calculations. The collecter location will be monitoring the whole bank. My theory is that located on #8, and being at the back of the intake, less air is being "seen" so calculations by the ecm are different. (mine is a MAP stradegy so the tune is effected more easily from mods).
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From: The Motor City
Originally Posted by honda hunter
Most of the time in closed loop my blm's were at 160. I'm converting to heated and moving the sensors to the proper place in hopes of solving my horrible drivability issue.
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From: Queensland, AUSTRALIA
Id shift the O2s to the collectors and retune it. Ive asked this question a few times and no one seems to be able to give any kind of straight answer. (until now, thanks mseven, that has been the best bit of info ive seen so far)
Mine on the 94 read from 2 cylinders on each side, and the 3rd sensor is mounted in the final collector. (which i thought was meant to be after the cats)
Mine on the 94 read from 2 cylinders on each side, and the 3rd sensor is mounted in the final collector. (which i thought was meant to be after the cats)
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From: Manama Bahrain
Well wouldnt you know, that's what was wrong. Now that the O2's are where they belong the car runs like a dream except for the idle which is at 1k-1100 rpm's. I think I need to play with the screw to get it down to 900. I'll fix that and adjust the P/T driving tommorow. Thanks everyone for the idea's and help.
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From: Manama Bahrain
Originally Posted by Casethecorvetteman
No you dont need to play with the screw to get it down to 900. Set it properly!!!! 
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From: The Motor City
Originally Posted by honda hunter
It was set for 900 in the tune. When I was troubleshooting the bad idle issue I played with the screw alot. Now I need to get it back to were it's suppose to be. I cant remember what the IAC counts should be at idle. I think 35 or so.
What I've found is when the car is at 128-129ish and it is @40 counts, if I richen it up (either through the ve, or pressure) counts will drop. Lowering the fuel pressure or in the tables will raise the counts (and possibly change the idle speed). I am not sure if the MAF stuff is as sensitive in that way.
Last edited by mseven; Oct 27, 2006 at 12:29 AM.
