S10/T10 Blazer 4WD V6-262 4.3L VIN W CPI (1992)
EGR Valve: Description and Operation
Exhaust Gas Flow
NOTE The linear EGR valve is used on all 4.3L VIN W engines. The
linear EGR valve is also used on all 4.3L VIN Z engines with California emissions and automatic transmision. For 4.3L VIN Z engines without
California emissions, refer to Negative Backpressure EGR Valve.
PURPOSE
The Exhaust Gas Recirculation (EGR) system is designed to lower NOx (oxides of nitrogen) emission levels created by high combustion
temperatures.
The Linear EGR valve is operated exclusively by Control Module command. To effectively operate the Linear EGR valve the control module
monitors various engine parameters:
-
Throttle Position Sensor (TPS).
-
Manifold Absolute Pressure (MAP).
-
Coolant Temperature Sensor (TPS).
-
Pintle Position Sensor (PPS).
Output messages are then sent to the EGR system indicating the proper amount of exhaust gas recirculation necessary to lower combustion
temperatures. This electronic metering of exhaust gas is ten times faster than vacuum operated models and offers improved diagnostic capabilities
as well.
