Engine System - LPG165Service Manual – CS7000There are several conditions that will override the user’s engine speed request.• High pressure wash forces to run speed.• If the engine is at idle speed, the engine will be forced to the run speed when sweeping only or vacuumingonly. The force idle (neutral timeout) will return the engine to idle speed.• If the engine is at idle or run speed, the engine will be forced to maximum power speed when scrubbingonly or scrubbing and sweeping. The force idle (neutral timeout) will return the engine to idle speed.• If the override is run speed, the user can change between maximum power speed and run speed.• If the override condition goes away (e.g. sweep system turns off) and the user has not changed the enginemode, the engine is returned to the mode before the forced override.Normal Engine Shut OffStep OneWhen the key switch is shut off, the main machine controller stops sending 12v out the ignition requestcircuit. This removes the power source for the fuel lock off solenoid that had been flowing through the “closedat rest” contacts of the high coolant temp shut down relay. No more fuel will flow into the vaporizer/regulatorbut the engine continues to run on the fuel that is “trapped” in the regulator.You may recall that when the key was first turned on, that the ignition request voltage energized theignition request relay and provided power for the ignition system. If this is true, how can the engine stayrunning after the ignition request voltage is shut off by the main machine controller? It is able to stayrunning because the energized power relay is providing battery power to the ignition request relay keeping itenergized so that the ignition system is still powered up.2135 4IGN. REQUESTMAINCONTROLLERFUELLOCK-OFFSOLENOIDOIL SWITCH(OPEN FORPRESSURE)TEMP. SWITCH(OPEN FORNORMAL TEMP.)RUN ENABLE SIGNALSHUTDOWN ControlCRANK REQUESTIGNITION REQUESTENGINE RUN (12V INPUT)HIGH COOLANT TEMP SignalSPEED 2 (12V OUTPUT)SPEED 3 (12V OUTPUT)Eng. RPMSensorSTARTER12v BATTERYALTERNATORIGNITION POWERFOR IGNITER &HIGH COOLANT TEMP.SHUTDOWN RELAY1 5 432CONTROLRELAY1 5 432IGNITIONREQUEST RELAYPOWERRELAY1 5 432LOW OIL PRESS.SHUTDOWNRELAY 1 5 432CRANKREQUESTRELAY1256 789101112WOODWARDL-SERIESACTUATOR341 2 3Main MachineControllerCarb.FuelShut OffSolenoid8586 8787a3012v
