85 engine electrical.pdf - Vintage Snow

ENGINE ELECTRICALSystem III - Electronics TestingThe ECU determines the amount of fuel to be injected by accurately calculating the engine's needs for fueldelivery. In order to do this, the ECU is loaded with a memory chip for the read out of the three dimensional mapwhich reads the throttle sensor and engine speed. Various sensors such as air temperature sensor, coolanttemperature sensor, barometric pressure sensor, battery voltage and the MR setting in the ECU are also inputs tocontrol fuel delivery.Select Monitor ReadingsMode Description Normal ReadingF100 Model Year Year of machineF01 Engine Code Polaris code number 30 for TriplesPolaris code number 20 for TwinsF02 Battery Voltage 12.2 or aboveNOTE: Type I system will indicate a f1iQh battery voltage on the select monitor if the actual voltage is belowapproximately 10vDC. If you suspect a low battery, use a Fluke meter to directly measure the battery voltage.Type II systems do not have this problem. The select monitor accurately reads battery voltage.RPM SensorThe Electronic Control Unit receives an engine RPMsignal from the COl box. This signal is one of the maininputs and is \(~ry critical to proper operation. If theECU does not see this' signal, the injectors will notopen and the fuel pump will only cy~le for the initial fiveseconds when the ECU is powered up. (See page4.36).The ignition switch anq, aux11iary kill switch areconnected in series wi h the E0U COl signal. If theseswitches are leaking partial voltages to ground, theECU will not function properly. Whenever COlorintermittent running problems are occurring, theswitches should be suspect for potential problems.These switches will also fail more often when humidityis high. To troubleshoot the switches, disconnect orisolate them from the circuit.''"'RPM OUTPUTSelect Monitor ReadingsModeF03DescriptionEngine RPMNormal ReadingCranking 300-5008/944.54