O2 Sensor Problem

Chrisfol82 · Post by **Chrisfol82** » Mon Jul 10, 2006 4:47 pm

I seem to be having a problem with my O2 sensor. When run it with megatune it seems to only get readings between about .17 and .41. Usually it will just stick to one of these values. If it goes lean it will go to .17 if it gets a little richer it will go to .41. Sometimes it will vary between these two values.

But when i hook up my voltmeter to my O2 sensor i get values up to about .56. Shouldnt i be getting the same reading off my voltmeter that i am megatune.

No matter what though i cant get a reading above about .56 though even if i richer it up so much it will barely run. So i know somethin must not be right with my O2 sensor. Which is understandable since it is about 20 years old.

But i was thinking about getting a wideband and i didnt want to get one right away if there might be a problem with the computer rather than just with the O2 sensor itself.

Bernard Fife · Post by **Bernard Fife** » Mon Jul 10, 2006 10:49 pm

Chrisfel82,

This is a known issue with some MS-II codes. To fix it, 'calibrate the AFR table' (under tools) to DIY-WB. Click OK, and let the 1024 values burn. Then shut off MegaTune, cycle the power to MegaSquirt, and restart MegaTune. Go to 'calibrate the AFR table', and set it to narrow band, then click okay, and let the 1024 values burn.

After that, it should read correctly at all times. You won't have to do this again unless you burn new code to the controller.

Lance.

Chrisfol82 · Post by **Chrisfol82** » Tue Jul 11, 2006 9:00 am

Thanks ill try that tonight