Rear oxygen Sensor in OBDII s14 Question

[stunnaben]

I have a 1997 240 and I went to get it inspected. I have no rear 02 sensor in my car. I have a CEI for it but I only have to pass safety inspection and they failed me due to the not having a rear 02 sensor. Do I need one? How does not having this sensor affect performance or anything for that matter? Thanks guys.

[0wn3r]

You have a check engine light for it?

Why do you stop at a stop light even though the road in front of you is paved? It's the same for your OBDII testing, it finds an error "red light" and stops because it assumes something is bad. Some states probably separate safety inspection from emissions testing, but sounds like you're getting both in one.

They don't care what you're actually emitting...they care about plugging in the computer and making sure it scans properly. I doubt they even care what's coming out of your tailpipe and (at least in a few states) won't do a sniff test as a substitute. It's either plug in and pass or plug in and fail.

Now try passing when you have an SR...

[stunnaben]

No, the inspections are different here. I don't have the emmission testing. They don't hook into the computer or anything. It's basically a visible test. They failed me on balding tires 02 sensor and an exhaust leak.... Stupid stuff. But like I was saying does not having the rear 02 sensor hurt anything? What does the computer do without the sensor? Anything different? I can pass all day long with an SR because I'm not in an emissions county. No sniffer testing no anything. Basically just pull in they look at the car and write it up. Good to go. It's just my 02 sensor wire was dangling down and they busted me for it :/ I believe the car has a 3 wire sensor in the bung hole but the plug is for a 4 wire sensor. It's like a square 2x2 plug on the harnes and the sensor in the hole is a 1x3 plug. Does that make any sense?

[projectRDM]

The '97-'98 rear O2 sensor is a 4wire, standard size bung, the early models are 3wire, small bung.

The ECU reads it as verifying catalytic converter function, that's the sole purpose of the rear O2 sensor. Engine performance is not affected with it removed, the ECU just assumes the converter isn't properly functioning and warns the driver of this.

[stunnaben]

Anyway to get rid of the CEI?

[g6civcx]

You can try an O2 simulator.