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and when it is reading from this part of the map, it is listening to the knock sensor. If knock is detected, it retards timing not by switching maps, but it is internal to the subroutine for knock control. The only time it reads from the low octane map is when it is in fault mode. But even still, there is a knock zone in the low octane map which allows it to further retard timing if knock is detected. When I say it will finally kick into safety boost I am saying that when knock is detected, it WILL retard timing (while in normal mode). If it keeps on knocking, it will fault and enter safety mode. Then it is reading from the low octane map. But if the low octane map is the same, nothing has changed and then it begins the timing retard once again, starting from the specified point in the map and then trying to retard until knock stops. In this case, with a boost controller, when it reverts to safety mode, it will not lower boost and engine condition will remain the same. Ignition timing in the knock zone is variable - its a closed loop feedback system where it can alter the timing based on given input. This gives it the ability to retard timing even when it is in safety boost. However, the fuel map way out in high load land does not have this ability. So when it switches to the low octane fuel map, there is no more fuel delivered and it cannot deliver more fuel based on O2 feedback, because under high load, the O2 system is open loop. It reads and delivers exactly the amount of fuel specified in the map.
[ ashleypowers.com ]
[ agpowers@bellsouth.net ] [ Zemulator Information Sheet ] When pigs dance, you better get it on video... "You never really learn to swear until you learn to drive."
-George Carlin
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10:34:57 01/15/03
