the_supernerd

Does anyone know which wires are used to check the oxygen sensor on a carbureted 22R? I think that the check connector is a round green connector on the drivers side fender, but I am not sure which wires are used to check the oxygen sensor.

notanymore

i though the 22r didnt have an o2 sensor? i thought it was just for the efi

the_supernerd

California smog carbureted 22Rs have an O2 sensor for the feedback system.

stock87

There are a couple round plugs near the coil/igniter, usually plugged into a couple rubber holders on the inner fender. There should be a 3 wire one and a 1 wire one, I think it's the one wire one.

the_supernerd

Thanks for the info, that is where I figured it is. To test it, do I put a positive volt meter probe in the connector and the negative to ground?

stock87

Positive to the connector I believe. Analog volt meter is best so you can watch the needle sweeps.

http://www.4x4wire.com/forums/showfl...5&o=14&fpart=1

Might check the '85 FSM to be sure.

dcg9381

Or just unplug that sensor, if it's a single wire unheated.
probe it with +

the_supernerd

I probed all of the wires, but I only get voltage on two of them. One appears to have voltage when the EACV comes on, the other appears to be related to the EBCV. Nothing appears to be giving me an O2 sensor signal that I can figure out.

I tried unplugging the sensor and probing it. I get voltage, but I cannot see if the voltage fluctuates like it should because it is not in feedback since the oxygen sensor is unplugged from the computer.

dcg9381

The narrowband should give you 0-1v regardless of being plugged in or not.
Other than the single signal wire, the others are typically used to do heat (12v) and ground.

the_supernerd

The O2 sensor sends a signal. I get about a volt when I test it unplugged. The only problem is that I cannot see how accurate the sensor is doing it that way, or if the system is in feedback mode.

The other voltage signals I am talking about are on the check connector on the driver's side fender. It appears to be set up to attach to a special tool that would give readings for anything to do with the smog system. One wire is for the EBCV signal, one is for the EACV signal, and the other two I have not figured out yet. One must be for the O2 sensor and I am thinking that I am probing it wrong.

Anyways, thanks for all of the input. I will post back when I get all of those wires figured out to help anyone else that needs to do some smog system diagnostics.

dcg9381

If you want to test the 02, testing it unplugged is fine. Typically it's plugged into a very high impedance circuit, so plugging it in shouldn't matter.. Test it while plugged in if you want.

The sensor should be very dynamic when hot.

The other signals, you'll have to get from the FSM.