For those who are following my learning curve about webers and emissions on my Brat, you might have noticed I'm looking for a way to check mixture on my Brat without paying some emissions shop $$$$$$$$ to sniff while I change idle jets on the weber. Anyway, oddcomp suggested using the existing O2 sensor and making a display/readout to monitor the sensor and have some idea what's happening to the mixture. Anyone here have some idea what the output of the O2 sensor is? I suspect it's resistive; what kind of values could I expect for rich, lean, and in-between. Anyone seen any "homemade" displays that would do what I'm looking for?

Somewhere on the internet there should be an article about how to use your DMM with an O2 sensor to measure you mixture. I just can't remember where I found it.

why yes. I just hapen to fully under stand the workings of the good old O2 sensor.

no. resistance bad. voltage good.

ok so I am sure I have explained this before but here we go again. the O2 sensor outputs a 0 to 1Volt signal that it generates.

the higer the voltage(.6v to 1v) means it sees verry little O2 in the exhaust. this usually means its a rich mixture.

 

a low reading (.4v to 0V) means lean or too much O2 left over. This may also mean misfire. incomplete combustion and O2 left over.

 

so yes O2 can help you dial in a car but be carefull it can also mislead you.

on a carbed car it is almost impossible to get it to run at a perfect .5 volts so just try to get it as close as you can.

on fuel injected vehicles the ecm should be driving the mixture from rich to lean in miliseconds thus the fluctuating O2 signal on a warm injected car with a good sensor. this makes the cat. converter work most efficently.

 

yeah. ok. I will stop now. most of you probaby dont really care how the O2 effects the car.

Hey Ed goto the book store or where ever you can find Grassroots motorsports magazine and they have a how to for a wide-band system in the latest issue

 

just picked it up today and saw that