100S Quattro Wagon (Canada) V6-2.8L (AAH) (1992)
EGR Valve: Testing and Inspection
TEST PROCEDURE
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Disconnect vacuum hose from EGR valve.
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Connect a hand vacuum pump to EGR valve.
NOTE:
DO NOT run engine during this part of test.
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Using hand vacuum pump, apply vacuum to EGR valve.
^
Vacuum should hold without dropping.
If vacuum drops, or will not build up:
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Check hose connections for leaks
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Check vacuum pump operation
If pump and lines are OK:
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Replace EGR valve
If vacuum holds:
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Release vacuum.
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Start engine and let Idle.
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Using hand vacuum pump, briefly apply vacuum to EGR valve.
^
Idle must become rough and/or engine dies.
If Not:
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Check EGR valve for blockage.
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Check tube from exhaust manifold to EGR valve for blockage.
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Check passage in the intake manifold for blockage.