D 250 Pickup L6-359 5.9L DSL (1992)
Cold Start Solenoid (For Injection Pump): Description and Operation
KSB Solenoid Valve
LOCATION
The KSB Solenoid Valve is located on the injection pump.
PURPOSE
When the KSB solenoid prevents venting of the injection pump pressure regulator, this causes the pressure inside the injection pump to increases
at idle. This pressure advances the injection timing. This prevents white smoke from the exhaust.
OPERATION
This valve is actuated by the electronic controller when the temperature of the intake manifold is at or below 59 °F (15 °C). This valve controls
the venting of pressure inside the housing of the injection pump. When the temperature of the intake manifold is at or below 59 °F (15 °C) the
KSB solenoid allows the pressure inside the injection pump to increase which allows the injection timing to advance. The KSB solenoid will
allow the injection pump to go to full advance as soon as a cold engine is started.
The KSB solenoid contains a wax pellet held in an expansion chamber, a heater that is operated by the electronic controller, and a check valve.
When the electronic controller sends voltage to the heater assembly (based on input from the thermistor) the wax expands within 30 to 45 seconds.
The expanding wax forces a plunger back against the check valve. When the plunger is against the check valve, fuel is allowed to vent from the
pump pressure regulator valve, reducing internal pump pressure. When the pressure in the injection pump is reduced, injection pump timing is
retarded.
