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The Vacuum switching valve controls the EGR Valve.
how does the 83 tercel thermostatic vacuum switching valve work
Defective modulator valve.
the valve is on lower side of engine near fire wall.
in between the intake manifold, bottom half.
Despite the rather lengthy name the EGR-VSV ( exhaust gas recirculation vacuum switching valve ) does little more than allow vacuum to flow through the system depending on engine coolant temperature. An element within the switch reacts to temperature changes, opening and closing the valve at a predetermined level.
The 2001 Chevy Impala vacuum module can be found on the back of the engine. The vacuum module valve will be near the top of the engine.
The VSV is located on the left side fender, on the curve of the wheel well. It is the middle valve of a group of three.
The VSV is located on the intake manifold side of the emission control valve set.
You would need a ported source for the distributor, constant for a pcv valve, constant for power brakes, and constant for transmission modulator if automatic.
The PCV valve is located on the top of the valve cover. There will be a large vacuum line connected to it.
That year model did not have a modulator valve on the transmission.