Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
EGR Valve: Testing and Inspection
Positive Back Pressure EGR Valve
1.
Check valve signal tube orifice for obstructions. On engines with an EGR-TVS, there should be no EGR valve movement below 85° F. If
there is movement, check the EGR-TVS for proper operation.
2.
Remove EGR valve from vehicle. Then apply a constant external vacuum supply, approximately 10 inches Hg or more, to the EGR vacuum signal
tube.
3.
EGR valve should not be open. If valve is open, the transducer control valve is stuck closed and EGR valve must be replaced.
4.
With vacuum supply still being applied, direct a stream of air from a low pressure source, 15 PSI, into the valve exhaust gas intake.
5.
EGR valve should open completely. If valve does not open, the transducer control valve is stuck open and EGR valve must be replaced.
