THEORY OF OPERATION
• Clear-flood mode (sub-mode) –is activated strictly
by a wide-open throttle or high TPS input. For this mode to be active, the
ECM must read a low engine speed value of under 600 RPM and a throttle
opening of 85 % or higher (usually W.O.T.). At this point, the ECM reduces
injector pulse to an A/F ratio of 20.0:1 or higher. In most cases, the ECM
cuts injector pulsation completely. All this is done in order to purge the
cylinders of excess fuel and correct a flooding condition. This mode is not
used on all fuel control system, which is why some systems will flood under
heavy cranking. A condition relating to this mode is an engine that will not
start due to a high TPS voltage and no injector pulse. In such case, the ECM
will perceive the high TPS voltage as a W.O.T. condition and activate the
clear flood mode, thereby, reducing or cutting injector pulse altogether.
The same can also happen if the TPS ground wire develops an open circuit,
which would cause a high TPS voltage input signal as well.
