B16A into '89 Rex--O2 sensor question

[Carl425]

I bought a 4 into 1 header off of eBay and though it appears to be a quality product, it only has one O2 bung in it located just behind the collector. I'm thinking it's
designed for OBD1 but the motor is OBD0 so I need the second O2 sensor. My question is how where should I put the second sensor? My initial thought was to plug the bung that it came with and put in two new bungs, one in the #1 pipe and on in #4, will this work? There's no non-ghetto way of putting a bung in so that it measures two cylinders at once due to the design of the header. I"m not willing to swap to OBD1 (not just yet anyway) and I"m not buying a different header either. Anyone's thoughts?

Carl425

 

[jason22ga]

i tried what your talking about it wont work your car will run like crap and vtec wont engage well at least mine didnt im using the stock jdm header that came with my swap until i convert to obd1

 

[TheManRSW]

Good luck. If I am not mistaken that engine requires two o2 sensors 1 & 4...and 2 & 3 for it to run correctly. With a 4-1 header...that is going to be pretty tough. Your best bet would be to keep the stock jdm manifold.

 

[TheManRSW]

I would stay with this manifold...it'll be pretty tough to make it work another way.

 

[Carl425]

Good luck. If I am not mistaken that engine requires two o2 sensors 1 & 4...and 2 & 3 for it to run correctly. With a 4-1 header...that is going to be pretty tough. Your best bet would be to keep the stock jdm manifold.

I know, it uses a 1&2 and 3&4 setup normally, that's why I was figuring I could just put two bungs and then put them in different cylinders (1&4 or 2&3, shouldn't matter) and should get the same result. All the stock setup is doing is using an average of the 4 cylinders by means of averaging two at the same time but, it won't know the difference between being in a tube that is shared by two cylinders or being in two distinct separate cylinders. That's my theory anyway. As long as I'm using tow sensors and they're placed equal distances down the tubes, just like the JDM manifold, then it should work. Any more thoughts?

 

[TheManRSW]

You can try. I have read numerous posts about people who have tried this...but the air fuel mixture will fluctuate rich to lean...due to cross counts of the o2's. I wouldn't try this, but I value a correct air/fuel mixture more than most.

 

[goldgreen90ef]

i have the same problem, and im getting my ecu chipped to not look for 2 o2 sensors...

 

[Carl425]

i have the same problem, and im getting my ecu chipped to not look for 2 o2 sensors...

Where are you having that done? And how much?

 

[goldgreen90ef]

obdo tuning

i think its called zerolift autolab in cincinatti ohio..........

 

[Carl425]

Yep, I checked with them and they said they can do this and that they will also do all the other things that most tuners do, more aggressive air/fuel map, bump the redline up, etc... for $150

 

[hondaman85]

any where else close to columbus that will do that?