1500 4x4 Pickup V8-318 5.2L Magnum (1994)
Engine Start-Up
This is an OPEN LOOP mode.
When the starter motor is engaged, the Powertrain Control Module (PCM) receives input from:
- Battery voltage
- Crankshaft position (CKP) sensor
- Engine coolant temperature (ECT) sensor
- Intake air temperature (IAT) sensor
- Throttle position sensor (TPS)
- Camshaft position (CMP) sensor
- Starter relay
Based on these inputs, the PCM will:
- Monitor crankshaft position sensor. If no signal is received within 3 seconds, the PCM will shut down the fuel injection system.
- Supply the injectors with a ground path, firing all injectors until the PCM determines crankshaft position.
- Determine proper ignition timing.
Engine Warm-Up
This is an OPEN LOOP mode.
During engine warm-up, the Powertrain Control Module (PCM) receives input from:
- Battery voltage
- Crankshaft position (CKP) sensor
- Engine coolant temperature (ECT) sensor
- Intake air temperature (IAT) sensor
- Manifold absolute pressure (MAP) sensor
- Throttle position sensor (TPS)
- Camshaft position (CMP) sensor
- A/C select switch
Based on these inputs the PCM will:
- Apply voltage to the injectors. The PCM then controls injection sequence and pulse width by switching individual injector ground paths on
and off.
- Adjust engine idle speed through the IAC motor.
- Adjust ignition timing.
- Operate A/C Compressor Clutch relay (if selected).
- Operate the Up-Shift indicator light.
- Begin to monitor oxygen sensor. When engine is at operating temperature, the system will leave warm up mode and go into closed loop
operation.
Idle
This is a CLOSED LOOP mode.
With engine idling at operating temperature, the PCM receives inputs from:
- Air Conditioning Control Position
- Battery voltage
- Camshaft position (CMP) sensor
- Engine coolant temperature (ECT) sensor
- Manifold Absolute Pressure (MAP) sensor
- Intake air temperature (IAT) sensor
- Crankshaft position (CKP) sensor
- Throttle Position Sensor (TPS)