hi all
i have just fitted an autometer afr gauge and am abit worried about the readings
on cruise it flicks about in the optimal section
on hard throtle it goes half way into rich
of the throttle and at idle it sits in the middle of the lean section but does twitch about in lean is this a normal reading???

 

afr gauge will read all over the place other than at full throttle...... the ecu is constantly adjusting the mixture for economy purposes so the led's will alternate between rich lean and anywhere in between.... even go completely off the scale on the lean side at times,as long as when you are on boost its showing a constant green rich mixture then thats what you are looking for..... mine is exactly the same,bit disconcerting at first with the light show,but you get used to it and ignore it till you run boost,being a narrow band sensor and gauge its not that accurate as to the exact mixture readings,a wide band is req for that,but to be aware that everything is running ok it works fine,just keep looking for the steady green when you floor it.

martin

 

great thanks i recently fitted a scoobyecu from ebay do you think the gauge is accurate enough to say the chip is running ok or should i get it tested with a wideband afr

 

A narrow band sensor is pretty useless for measuring AFR, It basically measures rich or weak, The only way of getting a true reading is by using a wideband lambda (e.g LC-1 or LM-1)

 

im using a specially made afr and it concentratesb on the 0.8-0.9v end of the scale and is therefore more accurate and reads well.