Intake Manifold Heater - Check

CHECK BATTERY VOLTAGE

The temperature In the Intake manifold must be below -90C [150F] (early module before serial number 0080000A) 150C [590 F] (late module) for preheat to occur.

Check the voltage output of the battery.

Minimum: 6.5 volts





CHECK THERMISTOR

Disconnect the thermistor.

Turn the ignition switch to the "ON" position.





NOTE: The Wait to Start" light should come on. The solenoids should click on.





Set the multi meter scale to read DC voltages.

Connect one lead to the KSB Valve wire terminal (A) and the other to a convenient ground on the engine (B).

There should be no voltage.





Wait 20 seconds.

The solenoids should click off.

The Wait to Start light should begin flashing.

NOTE: The wait to start light will flash indicating an open circuit in the thermistor wiring. Disconnecting the thermistor simulates this condition.





The multimeter should show voltage at the KSB Valve wire terminal. This voltage reading is an indication that the thermistor is sensing a temperature of 15°C [59°C] or above.

NOTE: No intake manifold postheat will occur while the thermistor is disconnected.





Turn the ignition switch to the "OFF" position. Connect the thermistor wire harness.

CHECK PREHEAT CYCLE





Turn the ignition switch to the "ON" position.

Do not start engine.





NOTE: If the intake manifold air temperature is below -9°C [15°F] (early module before serial number 0080000A) 15°C [59°F] (late module), the heater will preheat before the engine starts. This will repeat until the intake manifold air temperature increases to -9°C [15°F] (early module before serial number OO80OOOA) 15°C [59°F] (late module) each time the ignition key is turned from the OFF to the ON position.





The solenoids (2) should click on.

NOTE: If the engine has been running, the temperature is probably above 15°C [59°F]





After the preheat period, the "Wait to Start" light will go off and not flash.

Set the multimeter scale to read DC-voltage.

Connect the multimeter lead to the intake manifold heater terminals. Check each terminal individually.





If voltage is present, check the pull-in coil of the solenoids.

Check for voltage at the pulling coil of solenoid.

1. If voltage at pull-In coil replace electronic control module
2. If no voltage present at pull-in, replace solenoid





Start the Engine

Do not hold the ignition switch in the start position longer than 10 seconds.

If the engine does not start, turn the ignition switch to the "OFF" position.





Return the ignition switch to the "ON" position then begin the normal starting cycle again.





NOTE: If the intake manifold air temperature is below -9°C [15°F] (early module before serial number 0080000A) 15°C [59°F] (late module), the heater will again heat after the engine starts. This will repeat until the intake manifold air temperature increases to -9°C [15°F] (early module before serial number 0080000A) 15°C [59°F] (late module)