Chrysler 1991 Service Manual Supplement page 103

14 - i FUEL SYSTEM
Fig. 11 Air Temperature Switch
• The engine controller receives an ignition sense in-
put. It then powers up. Battery voltage is supplied
through the battery voltage input.
• The wait-to-start lamp is turned on by the engine
controller for at least 2 seconds as a bulb test.
• The engine controller monitors the charge air tem-
perature sensor input. If manifold air temperature is
at or below 15°C (59°F), the engine controller will
start the air intake heater preheat cycle. It will en-
ergize the intake heaters by grounding the air intake
heater relays. The engine controller will turn the
wait-to-start light on until the preheat cycle is over.
If the engine controller receives a crank signal
before the preheat cycle is over, it will abort the
preheat cycle.
• The engine controller monitors battery voltage.
The intake heater preheat cycle is adjusted based on
battery voltage.
@ The engine controller will turn on the water-in-
fuel lamp if a signal is received from the water-in-
fuel sensor.
ENGINE START-UP
When the ignition key is put in the start position,
the following occurs:
© The engine controller receives the crank signal in-
put when the starter relay is energized.
© The air intake heaters are not energized during
cranking.
• The engine controller monitors battery voltage. If
battery voltage is above 12.66 volts the engine con-
troller determines that the engine is running.
• If the engine controller received a crank signal be-
fore the preheat cycle was over, the heaters will be
de-energized. However, the post-heat cycle will begin
if battery voltage is above 12.66 volts and intake
manifold temperature is below 15°C (59°F).
ENGINE WARM-UP
• The engine controller may start the air intake
heater post-heat cycle depending on intake air tem-
perature. I f manifold air temperature was at or be-
low 15°C (59°F) when the ignition switch was turned
on, the cycle is started.
• If intake manifold air temperature is below 12°C
(54°F), the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en-
ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 16°C (60°F).
• If the coolant temperature switch is open, the
transmission will not be allowed to enter overdrive
(automatic transmission). The switch opens when
coolant temperature is below 16°C (60°F).
• The engine controller will turn on the water-in-
fuel lamp if a signal is received from the water-in-
fuel sensor.
CRUISS OR SOLE
• The engine controller monitors intake manifold air
temperature through the charge temperature sensor
input.
• If intake manifold air temperature is below 12°C
(54°F), the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en-
ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 16°C (60°F).
• The air intake heater post-heat cycle will be com-
pleted, i f it is not already over.
© The vehicle distance (speed) sensor and throttle po-
sition sensor inputs are used to control transmission
overdrive operation.
If the coolant temperature switch is open, the
transmission will not be allowed to enter overdrive
(automatic transmission). The switch opens when
coolant temperature is below 16°C (60°F).
• If the transmission thermo-switch is open, the
transmission will not be allowed to enter into over-
drive (automatic transmission). If the switch opens