Oxygen Sensor Placement

We may earn a small commission from affiliate links and paid advertisements. Terms

mauger

Junior Member
where do you put the 2 nd o2 sensor in a header or can you weld a bung i the cat? i have a 91 civic with a b16a w pr3 ecu
 

Larryd

Junior Member
:rolleyes: You should put the second bung at the same relitave spot as the sensors in the cast manifold. The computer reads the mixture in two pair of cylinders. The also have to be in the corect order. I think white plug is no 1.....Larry
 

legutki

Senior Member
i going through the same problem except im using a b18c w/ obdo injectors and dist. and a skunk2 intake manifold . the b18c only has i sensor before the cat.
 

D See 2

Senior Member
how could the computer tell which sensor was infront of which?... i think for the pr3 ecu, both o2 sensors should be relatively close to one another.
 

D See 2

Senior Member
here it goes loud and clear for ya... taken directly from a b16a1 crx manual... using an obd0 pr3 ecu... notice where the two oxygen sensors are placed? in the same fucking spot! getting readings from the same place.

o2sensors.jpg
 

legutki

Senior Member
Is there hi flow cats with holes already in there. i know there is a stock cat from a 95 gsr for sale and it has a o2 sensor on it. whats the performance diff between a stock and a hi flow?
 

wildbillhatchbac

the OG
VIP
OBD1 1 o2 sensor . . . in the manifold, before the cat

OBD2 2 o2 sensors . . . 1 in the manifold and the 2nd in or after the cat

OBD2 ecus can read the difference between pre cat and after cat exhaust oxygen levels . . . if you have no cat or even some high flow cats will or can through a code . . P0420 catylist deterioration
 

legutki

Senior Member
I found out that pr3 can be reprogrammed to read only one o2 sensor. for more info look at gbrtuning.com or email greg at vtec4gs@aol.com :D
 

D See 2

Senior Member
Originally posted by legutki@Apr 9 2003, 08:41 AM
I found out that pr3 can be reprogrammed to read only one o2 sensor. for more info email greg at vtec4gs@aol.com :D

yea, hondata can also do that, its called making your ecu run in open loop mode. a closed loop mode will read both oxygen sensors.
 

D See 2

Senior Member
Originally posted by pills_PMD@Apr 9 2003, 10:25 AM
i thought open loop didn't use O2 sensors at all??>???

exactly, open reads none, and closed(stock setting) reads both
 

pills_PMD

New Member
but he said that you can reprogram it to read ONE o2 sensor.. and you said hondata can do that and make it run open loop. nevermind lol
 
Top