97 Civic dx with 97 ls swap. however for some reason it has an obd1 exhaust manifold with only room for one O2 sensor. After searching I found out the second O2 sensor on obd2 vehicles has nothing to do with engine managment and i could just leave it plugged in dangling in midair (something about it would always read leaner than the primer O2 and the ecu would think everything was ok).

But my primary O2 is near the end of the down pipe instead of up near the motor. Anyway the car has a very ruff idle and you can smell gas really bad. After looking at the plugs I believe it is running too rich (hints the gas smell). But could my O2 sensor problem have anything to do with this??

PS: I have no CEL. Ive replaced, plugs, wires, cap, and rotor button, & alternator.

Thanks for all your help
Ben

 

Which ECU are you using? Have any check engine lights? The OBD1LS and OBD2 LS O2 locations are the same on the exhaust manifold. The 2nd O2 is either after the catalytic convertor or in it. So if you are using an OBD2 ECU you will still need to have this connected to the O2 plug.

 

no their arent any CEL. and its the obd2 ecu. and I just searched and found out youre right the obd1 and obd2 locations are the same. So I am not sure what exhaust manifold I have. But there is only room for one O2, no where to plug the primary O2 sensor. Just the secondary near the cat.

 

Your right the primary is the only one that the ECU uses to control the A/F ratio. The secondary is only used to determine the efficiency of the catalytic convertor. The fact that the sensor is located so far downstream doesnt make a difference. The same exhaust gases pass by as they would at the manifold. You are using your primary sensor right? By the way, I have a ECG Electronics Secondary o2 sim box for sale. It worked perfect in my Civic!

 

actually I found out that I have the correct manifold on it. and the secondary O2 is located on the midpipe after the cat. I believe my O2 sensor is the problem. but can an O2 sensor be bad without throwing a CEL?

 

no. If theres anything wrong at all with the O2 it would throw a code. Your problem is somewhere else, not your O2 sensors. are you sure your Check Engine Light is operational. when you turn your key on it should light up for a second or two.

 

yea it works. what about a leaking headgasket? the exhaust is always blowing out water it seems. could this effect the idle? but dont seem to be losing alot of coolant and the oil looks good

 

Is it blowing out condensation or coolant?