Hi All,

tried searching but couldnt find much on what i am after.

Can anyone advise how i can convert the NB voltage to an AFR? is there a chart of some sort for an Evo 9 i can reference?

At idle, i want to see what the NB voltage/AFR is compared to my LC1 but dont know how to interpret the voltage to an AFR reading.

cheers

 

the narrowband doesn't return an afr. It only returns a rich or lean voltage (usually 1.1 for rich and .1 for lean) based around 14.7 afr. So basically during closed loop where the ecu is using the narrowband to keep the afrs at 14.7 if the voltage says lean, it adds fuel until the voltage says rich, then it takes fuel out until it says lean, etc. etc. It does this pretty quickly to try and keep the afr at 14.7.

hope this helps.

 

i understand that, i was more hoping to get something like the below...

0v ~ 14AFR
.5v ~ 14.7AFR
1v ~ 15.4AFR

My LC1 at idle/cruise hovers/averages around 14.3AFR. I am hoping if i can correlate a voltage to an AFR (loosely) i can confirm if the LC1 is reading correctly or not.

so if i took the above as an example and logged the NB voltage and it ended up hovering/averaging .2-.3v then i know the LC1 is relatively accurate. If it averaged .5v, then i would estimate that the LC1 is .3-.4 AFR off.

not sure if this is possible, but am hoping

cheers

 

the lc-1 gauge is reading 14.3? you might need to calibrate it again. I used to have the lc-1 and it was kind of a pain in the *** to get calibrated correctly. I would consider your LC-1 is reading wrong before your car would idle much off 14.7.

 

its a brand new sensor and did the free air calibration as per instructions.

the old one wasnt holdng the calibration for mroe than 15min so bought a new one.

ill see what happens

cheers

 

welcome to the world of the lc-1, if it strikes you try the mtx-l I've had var better luck with that than I did either of my lc-1s