First O2 pointless after Cat removal?

[dsmud4u]

As the zombie killer goes on a diet (LPSV, ABS EGR) do I cut a hole in the new Pacemaker header (has bung welded) to fit the O2, for performance/ fuel economy.

The truck has remained in open loop since the install and I still need resistors for the rear O2 and EGR. Just wondering if it’s worth having the first O2 or if it makes near as no difference.

The truck is a 97

 

[Kernal]

@landtank will explain it better but the pre-cat O2 sensor is the critical position for the FZJ80/1FZFE otherwise it will always run rich, like the engine after a cold start before it switches to Closed Loop.

 

[landtank]

The pre-cat O2 sensor sets up the fueling for the entire system. If you develop a small air leak it will adjust the fuel trims to compensate for the extra air and protect the engine from running lean. Using resistors to trick the ECU is one of the best ways to damage your engine. As it’s a static setting and fueling issues won’t be compensated for.

 

[dsmud4u]

Thanks gents, will reinstall the primary O2.

 

[landtank]

The post CAT O2 can be tricked to eliminate the code that will occur if a sensor isn’t in place and seeing the expected reading.

 

[Gascan]

The post CAT O2 can be tricked to eliminate the code that will occur if a sensor isn’t in place and seeing the expected reading.

Any chance you could go into detail or link me how to trick the rear O2?

 

[TX80CC]

Any chance you could go into detail or link me how to trick the rear O2?

I would like to know as well

 

[LXDOC]

Google post cat O2 emulator or try an O2 sensor spacer (cheapest).

 

[landtank]

Any chance you could go into detail or link me how to trick the rear O2?

Never investigated how to do it. Just read that it could be done.

 

[Marvelicious]

No idea if anything in this thread will work, but it's worth a look:

Toyota-4Runner.org

The Largest 4Runner Community in the World

www.toyota-4runner.org

 

[Kernal]

IDK about this product, but JAF appear to be located in Ireland
RankOne's parent company may be located in Bulgaria, hard to find information and not listed on their website so might be risky to order

Both however show the device to be Out of Stock.

(Just listing this for discussion, not a recommendation)

O2 SENSOR EMULATOR (POST-CAT) FOR LEXUS/TOYOTA

Used to fix the P0420 and P0430 error codes caused by lowered efficiency of the catalytic system on modified cars. Whether your car has a de-cat, the engine is modified or it's just showing its aging catalytic system, the P0420 and P0430 error codes can be very annoying and can cause a failure...

jafperformance.com

 

[dsmud4u]

I seen those too. Oddly after reinstalling the upstream O2 my CEL went away but the code was a P0125. “Insufficient Coolant Temperature for Closed Loop Fuel Control“