Ok I'm in the process of redoing my exhaust on my h22a swap.when I pulled my old header off and notice the hole for o2 sensor was blocked off...I'm assuming previous owner was gonna turbo car..I want to put o2 sensor on new exhaust will that effect anything or should I block it off again

 

need a little more info-

what year and car is it?

is it obd1 or obd2?

Aftermarket header, or stock manifold?

what ecu are you using? has it been tuned for closed loop or open loop?

 

94 Integra with redtop h22a....obd2 aftermarket header p13 ecu...not sure bout open or closed tuning....unless it was done before I bought car...I pulled motor and rebuilt it just gotta fix exhaust issues running rich also

 

Well a P13 is a Obd1 factory prelude non-tunable ecu. Since it cant be tuned then it is in fact looking for a o2 sensor. obd1 only has one O2 up stream of the cat, and Obd2 has two O2's one before and after the cat.

Open and closed loop means the computer either feeds off of outside information from sensors to run. Or it doesnt and runs the same regardless of conditions. I get the names mixed up, but i believe the open loop uses sensors, and closed doesnt.

The factory o2 bung is on the header, and aftermarkets are usually on the down-pipe.

How was the O2 bung blocked off? welded or a screw/bolt?

If it was welded shut just buy a new bung and have it welded on anywhere before the cat.

http://www.ebay.com/itm/O2-Oxygen-sensor-Weld-On-Bung-Fitting-Wideband-Mild-Steel-Turbo-M18x1-5-Honda-/290923275901?pt=Race_Car_Parts&hash=item43bc60e67d&vxp=mtr

 

My bad it is on the downpipe and its welded

 

For an OBD1/JDM car/ECU, you need ONE O2 sensor. As long as you have the lrimary O2, you'll be good. The OBD1 harness will only have one plug on the harness for an O2 sensor. The location of that sensor would be in the downpipe...before the cat.

You need ONE sensor to control closed loop fuel trim.

 

I dont know why I always forget which is called which and mix them up, but same difference lol. So open loop doesn't need a O2 sensor, but closed does. Thanks for clearing that up.