okay I search for hours before posting this question. I recently bought a AEM wideband my question is I simply want to use it to monitor air fuel ratio readings.can I weld in the extra o2 bung and keep stock o2. red 12volt black thermostat ground and run white wire to eld 0.5 output and BOOM CALL IT A DAY.. sorry car is h22hatch turbo 9.1 on water meth professionally tuned on hondata s300 before u say it I no I can run through hondata I just don't no how to use s300 and I want wideband to monitor thanks in advance

 

yes you can weld in an extra O2 bung and keep stock O2. The ground wire for the UEGO should be an isolated one. You can plumb the white wire from the gauge into a spare 0-5Vinput on your S300. You will have to log into the software and calibrate the AEM sensor. At this point it would be your choice to run O2 feedback.

 

Yeah, its always interesting to see at what AFR/lambda your engine has been tuned to by monitoring it independantly.
Make sure you watch it in lambda as fuel calibrations (different blends have different AFR for lambda 1.00) can vary and your ecu may be tuned for it, your separate monitor may not be. Lambda 1.00 = lambda 1.00 for any fuel.
Also carefull to weld in the bung about max 45 degrees from vertical so it doens't flood/catch moisture from condensed water on cold start-ups.