How do I get round the rear O2 sensor? Wire chopped coz sensor was rotted into the cat when I removed it to fit a decat pipe. It’s throwing a cat converter red light up on the dash. Pre cat O2 sensor is still fitted and not been messed with. Obvious it’s gonna read different even if it was in the pipe. The car drives mint and is rapid but it’s using a lot of fuel (more than normal). And also a smell of I burnt fuel after booting it .Can anybody shed some light on what I can do about it as the red light is beginning to ■■■■ me off somewhat, keep thinking I’m harming it driving it with that rear sensor chopped.
assuming this is a 3000gt there is a method where you install a resistor into the wiring to stop the light from coming on, don’t know how effective this is though I would imagine though it would still overfuel if you aren’t running aftermarket fuel control and using a stock ECU. It’ll still be looking for the signal and not alter the fueling.
I’m toying with the idea of buying a stand alone management and getting someone to map it for me but there dear and for now need a cheaper solution as we’re off on hols in it in two weeks so could do with it running right. I’ve welded a small pipe about 2 inches long 90 degrees off the exhaust pipe to house a new rear 2 wire o2 sensor. Hoping that taking the probe out of the main flow of exhaust gas will simulate a clean burn reading… Am I on the right track? Also do I need to do something to reset the fault code after spacer and new sensor is fitted?
think on that one it will simply work again as intended and the cat light will go off.
Otherwise just take the bulb out 
I know yeh I thought about it but I’m started to get loaded off the petrol fumes after booting it 
The sensor in the Cat is only part of the circuit to turn the red lamp on in the dash board to warn you that the CAT is over heating.
It plays no part in what the ECU does with the fuelling on your car.
If it is coming on the cat is getting very hot and over heating which is the lights purpose to tell you it is doing so.
Does that car have any other symptoms apart from using loads of fuel as it should not under normal circumstances smell of fuel even when driven hard
The two wire sensor you are suggesting is a waste of time.
Fix the problem instead of inducing new ones
Have you checked to see if the 02 sensor/s are actually working ??
What car do you have GTO or 3000GT ?
Regards Rob
Remove warning bulb from dash.
That’s the light problem solved, as you no longer have a cat to overheat.
The overfueling is a separate, unrelated issue.
Marty
Rob, I think it’s a 3kgt but I didn’t even think there was a difference until I did some reading! Uve just answered my question anyways all I wanted to know was if that cat light meant anything like the brain goin into a default setting where it dumps ridiculas amounts of fuel in. But if it’s a pointless sensor I will pop the bulb. The engine management light would come up wouldn’t it if the mixture was wrong. 