White Smoke; Normal Operation Of The Intake Manifold Heater System - Dodge D250 1990 Service Manual

Air System
Page 11-8
Exhaust System and Intake Manifold
DODGE Turbo Diesel
White Smoke
White smoke indicates unburned fuel during cold engine operation.
The intake manifold heater system is not directly connected to the fuel system but it monitors the temperature of the
air to the engine. The thermistor sends varying resistance values to the Electronic Control Module. The ECM in turn
controls the "Walt to Start" light and the heater solenoids.
The intake manifold heater elements operate in both the preheat and postheat modes.
• In preheat, the ignition switch is on but the engine has not been started.
• In postheat, the engine is running.
The proper operation of the intake manifold heater system and starting procedures will preclude excessive engine
starter motor use and minimize white exhaust smoke when the engine is first started.
Normal Operation of the Intake Manifold Heater System
Engine Intake
Manifold Temp.
Above 15°C [59°F]
-90C to 150C
[15°Fto59°F]
-18°Cto-goC
[0°Fto15oF]
-26°Cto18°C
[-15°FtoO<>F]
Preheater
Cycle Time
Ign. Key "ON"
Before Crank
Cycle
O-Seconds
* 10-Seconds
15-Seconds
17-Seconds
Post Heater
Cycle Occurs
Ign. Key "ON*
After Crank
Cycle
No
Yes
Yes
Yes
Below -26°C [15<>F] 20-Seconds
Yes
Note: The KSB Valve activation voltage is independent of the Intake Manifold Heater Control System. The KSB Valve
will be activated any time the intake manifold temperature is above 15°C [59°F], the ignition key is In the "ON"
position and the ECM is monitoring the thermistor (reading resistance).
* Heater Control Modules / Electronic Control Modules with serial numbers below 0080000A will not have a Preheat
Cycle during this cycle.