o2 sensor

[4wheelsoffury]

I vaguely remember reading some info about the o2 sensor wires in the left underside of the dash, correct me please, but i think one connector is for a 50k mile warning lamp and a second connector for 100k warning. I had a lit sensor lamp for a while and I disconnected both connections and the lamp went off. All that is fine but I just cracked 100k, so I got a new sensor and installed it no problem, put connections under dash back to factory....the sensor lamp is still lit !!!! It has always ran fine, and I could tell no diff with new sensor, but I do not know if the sensor is operational, maybe it is supposed to run better and I just think its running fine ? Either way, I need to make sure the new sensor is alive, and the sensor lamp is all I have. Do I need to change the dash connections, or something else to make sure the new sensor is doing its thing ?

[PEZi]

yeah... i'm not sure how to reset or if its even possible... mine are still disconnected because it lights up if i connect them and everything is good to go

[fastboatman29212]

See my most recent post under my Build Thread. I thought that my SENSOR light was on because of a bad O2 sensor, but I think it may have been because of my bad oil pressure sending unit. I say that because after I replaced the oil pressure sending unit (which was leaking a little oil) the SENSOR light is OFF now.

Here's the post I'm referring to:

86-720-transformation-build-thread-t515055.html

[4wheelsoffury]

sweet !!! Only 8 bucks at autozone for the oil pressure switch, I'm all over it. I was just getting ready to change oil too, sometimes things just work out.

[fastboatman29212]

Let me know if that solves the problem. It did for me.

[4wheelsoffury]

...and if the o2 sensor is not operating, what are the symptoms ?

[breadbox]

possible rough idle and it'll run rich. At least that is what my 240sx does.

Does an 84 have an O2? can't say I remember.

[PEZi]

i know my '85 does... not sure on the '84

[fastboatman29212]

My 86 does. I'll check my 84 service manual just to be sure, but I'm pretty sure an 84 has an O2 sensor too.

[fastboatman29212]

I just spent 15 minutes looking through my 1984 service manual and I could not find anything labeled as O2 SENSOR. There is an EXHAUST GAS SENSOR listed, but I have no idea if that is the same thing or not.

Anyway, I guess I really don't have a good answer for you, sorry. I was pretty sure an 84 would have it, but now I really don't know.

[flinterman2000]

Yeah its the same thing. The O2 sensor checks the temperature of the exhaust gases just like the exhaust gas sensor.