#16129, "whats the lowdown on what the heck the afc really does"
i was just thinking about it, and really when we are just cruising around and our car is in closed loop monitoring all the sensors and crap does the afc really do anything, it appears to me that the car uses the o2 sensor to determine the proper amount of fuel to inject. am i wrong? i can see where the afc is useful when tuning WOT and idle with bigger injectors, but do our adjustments in the low range other than idle do anything for us when we are in closed loop? i would think not? if we lean out at say 2000 rpm in the LO range and we are cruising at this rpm and the map sensor "sees" less air than there actually is then the car injects less gas theoretically, but then the 02 sensor goes oh shit it's lean and then tells the ecu to inject more gas defeating the purpose. just wondering thanks james
#16131, "RE: whats the lowdown on what the heck the afc really does" In response to Reply # 0
Remember the stock ECU can only correct up to a point. so, yes, it does theoretically defeat teh purpose, but... If you watch your O2, it jumps high, low, high, low, etc. if you lean it out (theoretically lowering hte 02 voltage), you're cutting the top off of the wave. for example when it sees lean (say 0.2) sends more fuel, w/o and AFC, it might go to 0.8. If you've adjusted a set amt, it could only go to 0.75. BTW those are just random #'s I picked, but I think it gets the point across.
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