[highmiles]

What does the tailpipe wideband O2 sensor actually measure? Does having or not having catalytic converters or the type of catalytic converters have any effect on the readings and why?

thanks.

 

[SSSSSS]

I'm wondering this as well. I've had my o/r h for a year now without MIL eliminators. I took the light out of the dash but I'm wondering if the computer thinks the rear o2 aren't working and it making the car run rich.

John

 

[Modular John]

I'm wondering if the computer thinks the rear o2 aren't working and it making the car run rich.

The rear o2's have nothing to do with performance or driveability. They are simply their to tell the computer whether or not your converters are working. MIL emiminators fool the computer into thinking the converters are perfect working order. Thus, no check engine light. Hope this helps

 

[SSSSSS]

Thanks, that was what I was thinking but not sure.

John

 

[Christopher Ihara]

You can use a chip to turn off the rear efficiency sensors. Simply removing the SES light will not solve the problem.

 

[highmiles]

Will the A/F curves from a wideband O2 tailpipe sensor, be identical on the same car if ran with stock cats, aftermarket cats, and no cats? How?

I would think the curves would be different, but am not 100% sure. What exactly do wideband O2 tailpipe sensors detect?

thanks.

 

[highmiles]

Is the answer to my question so obvious I am missing the point?

I ask because the A/F tailpipe method is used regularly as a important measurement tool when tuning. And if the having or not having cats makes a difference on the readings, then shouldn't the tune be altered?

I have already looked in archives for the answer and dyno jet's website. They do not indicate what exact compounds they sample or monitor.

thanks.

 

[RedGTvert]

I have heard conflicting info from several different tuners. I have been told by one that the truer A/F reading is done when using an O/R, then another said the difference is minimal and to him it isn't enough of a difference to worry about.

Sorta like which one is better, attaching a bung to your pipes, or sliding a big old stick up your pipes.

My gut feeling is, the A/F will be more accurate without cats.