Index Chrysler Chrysler TOWN & COUNTRY, VOYAGER, Dodge Caravan - service repair manual 2001-2007 year
|
|
FUEL INJECTION OPERATION OPERATION - INJECTION SYSTEM All engines used in this section have a sequential Multi-Port Electronic Fuel Injection system. The MPI The PCM regulates: • Air/fuel ratio • Emission control devices • Cooling fan • Charging system • Idle speed • Vehicle speed control the PCM to correctly operate these systems. In addi- The PCM can adapt its programming to meet changing operating conditions. Fuel is injected into the intake port above the intake valve in precise metered amounts through The PCM adjusts injector pulse width by opening and closing the ground path to the injector. Engine OPERATION - MODES OF OPERATION As input signals to the PCM change, the PCM adjusts its response to output devices. For example, There are two different areas of operation, OPEN LOOP and CLOSED LOOP. During OPEN LOOP modes the PCM receives input signals and responds according to preset PCM sensor diagnostics (they are checked for shorted con- During CLOSED LOOP modes the PCM monitors the inputs from the upstream and downstream For the PCM to enter CLOSED LOOP operation, the following must occur: (1) Engine coolant temperature must be over 35°F. seconds. • If the coolant is over 50°F the PCM will wait 15 seconds. • If the coolant is over 167°F the PCM will wait 3 seconds. (2) For other temperatures the PCM will interpo- late the correct waiting time. (3) O2 sensor must read either greater than 0.745 volts or less than 0.29 volt. (4) The multi-port fuel injection systems has the following modes of operation: • Ignition switch ON (Zero RPM) • Engine start-up • Engine warm-up • Cruise • Idle • Acceleration • Deceleration • Wide Open Throttle • Ignition switch OFF deceleration with fuel shutoff and wide open throttle IGNITION SWITCH ON (ZERO RPM) MODE When the ignition switch activates the fuel injec- tion system, the following actions occur: • The PCM monitors the engine coolant tempera- ture sensor and throttle position sensor input. The • The PCM determines atmospheric air pressure from the MAP sensor input to modify injector pulse When the key is in the ON position and the engine is not running (zero rpm), the Auto Shutdown (ASD) 14 - 18 FUEL INJECTION RS |