wideband

Subydoug · Post by **Subydoug** » Fri May 24, 2013 9:20 am

Hi all,

Anyone got a wideband O2 sensor on a MPFI ea82 that would be willing to do a quick test for me?

Chasing a reference voltage from the stock o2 sensor.

Regards

Doug

steptoe · Post by **steptoe** » Fri May 24, 2013 9:48 am

I think Gannon did a four wire on his former EA82T , he may remember some details.
Hang on, you ask of wideband but want stock sensor readings, stock was single wire narrow band...I have one in reasonably new condition installed reading to my LED gauge

Subydoug · Post by **Subydoug** » Fri May 24, 2013 10:06 am

Yeah, usually they output a small voltage, under 1 volt. Just want to confirm the voltage out against an accurate sensor.

Regards

Doug

Gannon · Post by **Gannon** » Fri May 24, 2013 11:19 am

On a narrowband sensor, any voltage between 0.1v and 0.5v indicates a lean mixture, between 0.5v and 0.9v is rich. There is no 'in-between' because its a narrowband sensor.
A wideband on the otherhand is quite linear and can indicate exact values, but cant be read without a dedicated controller.

So are you borrowing a wideband clipped onto your exhaust tip to test your factory o2 sensor?

steptoe · Post by **steptoe** » Fri May 24, 2013 12:44 pm

So .... 0.5V is happy stoich ? I get the LEDs on my O2 reader from xxxxinstruments dance about giving various indications consistent with the tail pipe analyser, so not just a lean or rich read out, four bars either side of centre are used.

I got awful readings all over the shop when I shoved the wide band analysers sensor behind the turbo pre cat, yet nice and tidy at the tail pipe where it counts for pollution

Gannon · Post by **Gannon** » Fri May 24, 2013 1:36 pm

Because of the non linear operation of the narrowband sensor, it only produces 0.5v at exactly stoich mixtures. Because of this its impossible for an ECU to hold mixtures at this point so its much more reliable to swing the mixture back and forth slightly and use the oxygen sensor to reference the centre of the swing. This is why you display flashes from lean to rich and back rapidly. As the sensor ages, the response time gets longer until its too slow for the ECU to make use of.