Misc 101 Information

[Bruce Plecan]

In case you were ever curious, how often the ecm "looks" at
things.

The ECM never stops polling the sensors.  Under certain conditions, it might
ignore a measured value though.  Here's how often the XYZ
ecm samples the inputs:

MAP is sampled 160 times a second.

O2 is sampled 160 times a second.

VSS (MPH) is sampled every VSS pulse (up to 80 times a second.)

RPM is computed 80 times a second (in the spark code.)

TPS is sampled 80 times a second.

Battery voltage is sampled 10 times a second.

CTS is sampled 10 times a second.

ALDL is sampled 10 times a second.

MAT is sampled 10 times a second.

MPH is computed 10 times a second.

Fuel and spark are computed 80 times a second - on alternate 160 Hz beats

Most of these sampled items are filtered, so the value used for
further computations won't change as fast as the sample rate

Cheers
Bruce