o2 sensor question

[IanSzgatti]

would anybody happen to know what kind of 02 sensor the 97 3100s uses downstream behind the cat? Is it a regular type or a wide ratio air fuel sensor.

on a scan tool, I notice little change in voltage from the downstream o2, but before changing it, I'd like to be sure it's not acting as it's supposed to... wide ratio air fuel sensors can monitor very slight differences in mixture, and they don't behave like a traditional zirconia type sensor, which as you may know cycles from .1 v to .9 (ROUGHLY).

thanks

[SappySE107]

I think all wide bands work on a 5 volt range. I could be wrong but I don't know of any that would register the same voltages as a narrow band range of 1 volt.

[ForcedFirebird]

I don't think GM offered any WB 02's in 97. If it's a single wire, usually that is a NB, but seeing it is so far down the stream, it would probably have to be heated (meaning at least 2 or 3 wires) since a o2 need to see, what, 600*? If you first start the car (cold) and put a voltmeter set to mV on the sensing wire (usually purple or blue), and to ground, you should be able to get a near-rich reading due to the warm-up procedure. If it's more than 2v, then it's obviously a WB.

Ben, there are WB controllers that can send any signal you want. My LC-1 has programmable outputs and each (has 2 plus the minijack for a laptop) can simulate a NB, or WB output. It can also simulate a linear NB output, which was great for my AFR guage. Another cool feature is on these outputs, you can send signal in incriments, so you don't get that crazy bouncing of the AFRG (I like setting mine to every .3 sec).

[IanSzgatti]

Forced... this LC-1 you talk about... is that a performance programmer?

by the way... i passed my emissions test just by replacing the front heated o2... but the car was right on the limit for HC, and the noX and c0 where still up there a bit too... i think your right about there not being any WB on 97 GMs... but i had to be sure. I think the downstream works, but not as well as it could.

It forces another question though... if the catalyst is working properly, why would the downstream really show that much activity anyways.. even if its not a WB..

[ForcedFirebird]

Forced... this LC-1 you talk about... is that a performance programmer?

No it is a wideband sensor that can be monitored and programmed from a laptop to simulate a NB or WB sensor. I used mine to send a NB signal to my ECM, and another to my AFR guage, then the laptop to monitor actual AFR's.