GM 22048269 VALVE

To reduce nitrogen oxide (NOX) emissions, the Exhaust Gas Recirculation (EGR) system recirculates a small amount of exhaust gas into the combustion cycle to lower peak combustion temperatures where NOX is formed. There are exhaust passages in the intake manifold that facilitate efficient removal of exhaust gases. Vacuum hoses and EGR valve checkup are the main maintenance points, with TVS monitoring vacuum signals according to temperature changes in engine. Two types of EGR valves exist: vacuum modulated and exhaust back-pressure modulated, both with different ways of opening the valve. The EGR system is governed by throttle position and engine temperature so as not to allow recirculation at idle, during deceleration or when starting from cold condition for maintaining appropriate air fuel mixture. Rough idle is among the most common problems associated with this system, stalling and poor performance being others these can be solved through diagnosis and replacement of certain parts other than that. Diagnosis will involve; checking EGR valve movement; testing vacuum signal integrity and TVS functionality. Where need be, one can substitute either EGR valve or thermal vacuum switch referring to proper procedures for installation purposes.

To reduce nitrogen oxide (NOX) emissions, the Exhaust Gas Recirculation (EGR) system recirculates a small amount of exhaust gas into the combustion cycle to lower peak combustion temperatures where NOX is formed. There are exhaust passages in the intake manifold that facilitate efficient removal of exhaust gases. Vacuum hoses and EGR valve checkup are the main maintenance points, with TVS monitoring vacuum signals according to temperature changes in engine. Two types of EGR valves exist: vacuum modulated and exhaust back-pressure modulated, both with different ways of opening the valve. The EGR system is governed by throttle position and engine temperature so as not to allow recirculation at idle, during deceleration or when starting from cold condition for maintaining appropriate air fuel mixture. Rough idle is among the most common problems associated with this system, stalling and poor performance being others these can be solved through diagnosis and replacement of certain parts other than that. Diagnosis will involve; checking EGR valve movement; testing vacuum signal integrity and TVS functionality. Where need be, one can substitute either EGR valve or thermal vacuum switch referring to proper procedures for installation purposes.

The EGA valve is located in the intake manifold beside the carburetor. Most times, a jammed or rusted EGA valve will be the cause of emissions system failure. To verify if it's functional, put your hand below EGA valve when the engine is cold to avoid burns and manually press down on diaphragm. The diaphragm should allow you to perform some modestly exerted up and down movement in its case. If it doesn't move at all or moves with great difficulty replace it with another one of EGA.