3rd and final o2 sensor thread (hopefully), this time with MUCH more specific information! Options

[brianforster]

ok guys, i took the harness out to finally get to the bottom of this o2 sensor mess..

heres what we know

somebody told DMC (i assume qatar) and DMC told mark that the lower downpipe sensor (exhaust temperature sensor) was the o2 sensor.

they both ran the car without an o2 sensor, EVER!

for some reason they both got normal gas mileage and there cars ran correclty, except DMC sold hte car to mark with rod knock.

NOW heres where i need your help:

i traced the wire coming out of the ecu for ox1, (i do not have ox2) and it leads to a soldered connection to a grey wire which leads to the exhaust temperature sensor!!!! yes i know, GHETTO!

my question is: obviously i need to solder in my o2 sensor to the ox1 pin, but now where do i put the exhaust temperature sensor wire?

and more importantly, how the hell did two different "automotive enthusiasts" AND a tuning shop (quarter mile customs.. cough) not notice/remedy this?

This post has been edited by brianforster: May 5, 2006 - 3:22 PM

[phattyduck]

For this, I'm assuming you have a JDM 2nd gen 3s-gte... please correct me if this is not the case...

First, you can leave the EGT switch disconnected. Normal operation for it is 'open' so leaving it disconnected is perfectly fine (for the ECU, gauge cluster, and your car).

You will need to get a shielded O2 sensor wire hooked up to an O2 sensor. You can probably use any universal sensor for this. Connect the shield to the E1 or E2 ground wires near the ECU (and nowhere else) and then connect the O2 signal wire to the correct pin on the ECU. If you have access to your old harness, you can probably pull out the O2 sensor and wiring to run the same stuff from your 5s/7a.

-Charlie

[lagos]

here is how i think it works, after looking in my books
the 2nd sensor is called the Sub-Oxygen Sensor. not every motor got the 2nd sensor.

ox1 should go to your normal o2 sensor........
ox2 should go to the temp sensor. if your ecu dosnt have an ox2, then you dont need the temp sensor on there