> > Bentley wants us to adjust the AFM based on the CO content of the exhaust > gas > (not measured with the above unit). So, does anyone have good data on > what the > air:fuel ratio is supposed to be? > For gasoline, perfect AFR (called the "stoiciometric" ratio) is 14.7:1. No engine achieves a perfect burn, though, so for "full throttle" the ECU goes fairly rich. According tho the Bosch Fuel Injection & Engine Management book (Probst), max power is at 12.6:1, best economy at 15.4:1. The EFI system tried to stay on the rich side of 14.7:1, but as close to it as possible. Generally when you tune with a wideband O2 sensor you aim for right around stoiciometric and from there the ECU can handle the fine tuning. So long as you get it into the ECU's effective self-adjustment range, the CO, NOx, and HC should take care of themselves.
-- John Bange '90 Vanagon - "Geldsauger" |
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