How many of you guys run a single o2 in your downpipe, wired to both o2 sensor inputs on your ecu that would normaly run seperate pairs indepedantly in closed loop? any problems, suggestions?

 

Why all of us pre OBD2 guys!

Your post is a bit confusing, what are you looking to do? A close looped system only uses the first o2 sensor within the "loop". Lookup how a closed loop system works for details (my hand just doesn't feel like typing it). The 2nd O2 sensor is purely for emissions, it's to tell the brain 1)the cat is in place, 2)the cat is functioning properly, and 3)to ---- you out of hopes of performance.

There are many alternatives, seek and you will find the answers you are looking for (OBD1 swap, O2 Simulator + Test Pipe, aftermarket ECU)

 

Yea, I should have stated pre obd. obd1 works that way but not obd0. Obd0 jdm b series motors have two oxygen sensors total, one for each cylinder pair. Closed loop in our ecu's consists of running one pair lean...having the oxygen sensor see that its getting lean and then richening that pair out. Meanwhile the other pair is richening from the ecu, o2 says its richening, so te ecu starts to lean it out. Its an alternating pattern between the two pairs. Thats why if you are using the stock header with the o2's ports being only fed by a single cylinder pair, hooking up just one o2 to both ecu inputs, or switching the wires around by mistake makes the car run like ----. One pair is always lean, and one always rich.

My question is, to those of you with 0bd0 motors with one o2 hooked up in your turbo downpipe without running zdyne, uberdata, turboedit etc..., have you noticed any bad effects or does it run fairly well seeing as its reading all 4 cylinders. Does this make for any noticeable problems?

 

I would think almost everyone running a vafc hack or fmu is running their obd0 b series motors this way? What better way is there?

 

Ok, my obd0 b18a1 only has one o2 sensor in the dp, but then again, it's not a jdm. Can't really tell you what to do with a jdm motor.

But since you are obd0 just get one of the do-it-at-home rom editors and chip that bitch, safest way.

 

So do you run that single o2 in the downpipe with the stock ecu? Im just trying to see if it works without "noticeable" driving effects.

 

all the b18a1 cars I've seen are setup just like that. Single O2 inside the downpipe. I believe that should be all the obd0 usdm hondas, can't remember how the crx was setup. The o2 sensor is pretty close to the exhaust manifold, you can easily see it when standing at the bumper in front of the car.

 

no no no

obd0 b16's (runing pw0/pr3 ecu's) have 2 o2 sensors.

1 o2 sensor reads cyl 1 and 4 (in a 4-2-1 header)
the other o2 reads cyl 2-3

he wants to have a single o2 and split the wire to go to both ecu inputs.

Might be possible, might have bad milage/emissions. also might cause the voltage to drop.

 

See, that's what I get for not having any b16 motors around.