Comanche 4WD L6-242 4.0L VIN S MFI (1992)
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Throttle Position Sensor (TPS)
Based on the previous input signals, the following occurs:
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The fuel injector pulse width and injector firing sequence are controlled by the engine controller. The engine controller does this by switching
the ground to the injectors OFF and ON.
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The engine controller monitors the oxygen sensor's input, and changes the injector pulse width to keep the air/fuel ratio as close to 14.7:1 as
possible.
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The engine controller increases or decreases the ignition spark advance and ignition timing by applying and removing the ground path to the
ignition module.
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The engine controller controls the A/C compressor clutch via the A/C clutch relay, if the driver has selected A/C and if the A/C thermostat
has requested A/C.
Acceleration
This is an OPEN LOOP mode. When the engine controller receives a sudden increase in throttle position or MAP pressure, it recognizes it as a
demand for increased engine output. The engine controller responds by increasing injector pulse width to supply the necessary fuel for
acceleration.
Wide Open Throttle
This is an OPEN LOOP mode. When the engine is experiencing a wide open throttle condition, the controller receives the following inputs:
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Battery voltage
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Coolant temperature sensor
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Crankshaft Position Sensor (CPS)
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Manifold Air/fuel Temperature (MAT) sensor
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Manifold Absolute Pressure (MAP) sensor
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Sync signal
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Throttle Position Sensor (TPS)
Based on the previous input signals, the following occurs:
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The fuel pump ballast resistor is bypassed, allowing full system voltage to be applied to the fuel pump via the ballast bypass relay.
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The fuel injector pulse width and injector firing sequence are controlled by the engine controller. The engine controller does this by switching
the ground to the injectors OFF and ON.
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The engine controller ignores the oxygen sensor input signal and provides a predetermined amount of additional fuel by adjusting injector
pulse width.
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The engine controller increases or decreases the ignition spark advance and ignition timing by applying and removing the ground path to the
ignition module.
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If the engine controller receives inputs that indicate that the vehicle is experiencing a wide open throttle condition (and the A/C has been
selected by the driver), it will DE-ENERGIZE the A/C clutch relay (DIS-ENGAGING the A/C compressor clutch) for approximately 15
seconds or until the vehicle is no longer experiencing a wide open throttle condition.
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The upshift indicator lamp is controlled by the engine controller (Manual Transmission).
Deceleration
When the engine is at normal operating temperature, this is a CLOSED LOOP mode. When the engine is under hard deceleration, the controller
receives the following inputs:
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Air conditioning select signal
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Air conditioning request signal
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Battery voltage
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Coolant temperature sensor
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Crankshaft Position Sensor (CPS)
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Manifold Air/fuel Temperature (MAT) sensor
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Manifold Absolute Pressure (MAP) sensor
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Neutral safety switch (Automatic Transmission)
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Sync signal
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Throttle Position Sensor (TPS)
If the engine controller receives a closed throttle input from the TPS and a sudden decrease in manifold pressure from the MAP sensor, it
determines that hard deceleration is occurring. The engine controller will go into a fuel cut-off strategy, where it will remove the voltage from the
injectors so that they cannot fire. The engine controller also ENERGIZES the EGR solenoid and the evaporative purge solenoid to prevent EGR
