But isn't my car metered by MAF? If the MAF isn't detecting the extra amount of air going through it, because it's coming from another source, then how can it properly meter the amount of fuel? The 02 (without being broadband) is less about metering and more about general failure of the engine (extreme rich/lean), but the engine could still be slightly off-kilter (enough to show up on the plugs) and the o2 not pick it up.

I'm speaking only from experience of tuning a single turbo Supra, which may be another world altogether, but that beast ran 8:1 AFR when I had a monumental boost leak in it, the o2 didn't lean anything out at all, because the MAF was metering huge amounts of air, the ECU was dumping huge amounts of fuel.

 

Well, in the program you write in a correction factor. Lets say you figure 300 cu ft of air coming in, you just figure on it while writing your program. Also, on it's own, the ECM has a window of correction too.

 

Not quite sure what you are saying there aklim...

 

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