Wrangler L6-4.0L VIN S (2000)
Engine Start-Up Mode
This is an open loop mode. The following actions occur when the starter motor is engaged:
1. The auto shutdown and fuel pump relays are energized. If the PCM does not receive the camshaft and crankshaft signal within approximately
one second, these relays are deenergized.
2. The PCM'S energizes all fuel injectors until it determines crankshaft position from the camshaft and crankshaft signals. The PCM determines
crankshaft position within one engine revolution. After the crankshaft position has been determined, the PCM energizes the fuel injectors in
sequence. The PCM adjusts the injector pulse width and synchronizes the fuel injectors by controlling the fuel injectors' ground paths.
Once the auto shutdown and fuel pump relays have been energized, the PCM determines the fuel injector pulse width based on the following:
-
engine coolant temperature
-
manifold absolute pressure
-
intake air temperature
-
engine revolutions
-
throttle position
The PCM determines the spark advance based on the following:
-
engine coolant temperature
-
crankshaft position
-
camshaft position
-
intake air temperature
-
manifold absolute pressure
-
throttle position
Engine Warm-Up Mode
This is an open loop mode. The PCM adjusts injector pulse width and controls injector synchronization by controlling the fuel injectors' ground
paths. The PCM adjusts ignition timing and engine idle speed. The PCM adjusts the idle speed by controlling the idle air control motor.
Cruise or Idle Mode
When the engine is at normal operating temperature, this is a closed loop mode. During certain idle conditions, the PCM may enter into a variable
idle speed strategy. At this time, the PCM adjusts engine speed based on the following inputs:
-
throttle position
-
battery voltage
-
engine coolant temperature
Acceleration Mode
This is a closed loop mode. The PCM recognizes an increase in throttle position and a decrease in Manifold Vacuum as engine load increases. In
response, the PCM increases the injector pulse width to meet the increased load.
Deceleration Mode
This is a closed loop mode. The PCM recognizes a decrease in throttle position and an increase in Manifold Vacuum as engine load decreases. In
response, the PCM decreases the injector pulse width to meet the decreased load.
Wide Open Throttle Mode
This is an open loop mode. The throttle position sensor notifies the PCM of a wide open throttle condition. The PCM adjusts injector pulse width
to supply a predetermined amount of additional fuel.