96 OBDII stock ecu O2 sensor question
 

I am attempting to sort out a 1996 I just picked up with a JRSC setup on it. Obviously the previous owner who built the car never had to take it through emissions in their city/state.

I would like to get it through the plug in check here in my area and get it tagged before I delve into any additional modifications or tuning.

Currently I have no CEL on the dash or codes found on the reader. I do however have three Readiness Monitors that have not completed. EGR, Catalyst, and EVAP. I can pass with two readiness monitors not completed as long as one of the two is not the Catalyst.

I discovered that the PO had installed a resonator in place of the catalytic converter and the aftermarket mid pipe did not have a bung for a downstream O2 sensor. That original sensor was wire tied up against the tunnel in open air. There is no standalone or piggy back on the car. The JRSC kit consists of the older style MSD/sebring box to retard timing under boost. I believe it also has a rising rate fuel pressure regulator.

I ordered a replacement high flow catalytic converter yesterday. I took the mid pipe to the shop yesterday and welded in a bung for the sensor.
I also ordered a new downstream O2 sensor since I can only imagine the original is no longer working correctly after being in open air and exposed to the elements for what is likely many years.
I have not had a chance to trace the O2 wiring back to the main harness/ecu to see if it was modified in anyway.

My question is does the downstream O2 not trigger a CEL if it is not functioning or reading ambient air?
I am not that familiar with OBD2 ecu function but it seems odd to me that the PO could just tie up the O2 sensor and not trigger a code.

I am hoping the new O2 sensor and catalytic converter will allow the readiness monitor to complete so I can get this thing tagged.

I have a 97 and a bad downstream o2 will trigger a cell for sure, I just had to replace mine to pass emissions (only run stock ECU long enough to get yearly). You even need an OBD-II compliant cat (I use the Enthuza OBD-II) as a standard high flow cat will throw a code in my experience.

Yeah that is what I ordered. I talked to Jason at Enthuzacar yesterday to confirm size availability.

Now I just need to figure out what the PO did to not get a CEL with the sensor just hanging in free air.

Side note, hopefully this will help the car run a bit better until I make further upgrades/changes.

He didn't simply remove the CEL bulb, did he?

I don't think the downstream o2 affects fueling, pretty sure it's merely for emissions.

No, I got it to throw an ignition code and light up the CEL. PO also mentioned a CEL code and light he cleared when he left something in the evap system unhooked by mistake before restarting it.

I just love sorting out some other owners mistakes/band-aids.

I am going to have to rewire the stereo system as well since someone managed to install an amp in the trunk and run everything off the rear channel. It has no balance/fade adjustment capability between the door components and the head rest speakers. Also has a short in the drivers door components.