air fuel ratio
air fuel ratio not sure if this is the right forum but i would like to know what other peoples air fuel ratio guage's act like. mine under idle will stay mostly in the lean area and bounce to the middle of the stoich area. then when cruising it goes from very lean to the last yellow led to the right back and forth faster with faster acceleration, is THIS NORMAL?
TECH Enthusiast
Joined: Jun 2004
Posts: 576
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From: Fredericksburg, VA
Yep. The O2's constantly oscillate from rich to lean. The average of this rich/lean swing is the stoichiometric AFR. The PCM is constantly adjusting the AFR based on the O2 signals. O2's read rich, PCM leans out the AFR- then the O2's read lean, so the PCM richens the AFR. This is what causes the oscillation. The average of these oscillations is the stoichiometric AFR.
That's why you can't really read the AFR using a gauge on your narrowband O2's. But, it can give you an indication of how well they are cycling. It can also be used as kind of an idiot light that will tell you if your fueling goes way out of whack at WOT.
That's why you can't really read the AFR using a gauge on your narrowband O2's. But, it can give you an indication of how well they are cycling. It can also be used as kind of an idiot light that will tell you if your fueling goes way out of whack at WOT.
Last edited by Silverhawk_02TA; Jan 26, 2006 at 10:46 PM.
