System Tests: Corolla
- Start engine and warm to normal operating temperature. Disconnect and plug hose at distributor sub-diaphragm. Ignition timing should be 7° BTDC. Reconnect hose. Timing should advance to 15° BTDC.
- Stop engine. Disconnect 3 hoses from top of HAC valve. Blow air into each hose. Check that air flows into carburetor. Reconnect hoses.
- Remove check valve. Check that air flows from White or Orange pipe to Black pipe, but not in other direction.
- Remove distributor cap and rotor. Apply vacuum to diaphragm. Check that vacuum advancer moves in accordance with applied vacuum. Reinstall the rotor and distributor cap. Start engine.
- If at high altitude, disconnect vacuum hose between check valve and vacuum pipe at vacuum pipe side. Plug pipe end. Timing should not change for at least 1 minute. Stop engine and reconnect hose.
- If at low altitude, disconnect and plug vacuum hose from lower port of the HAC valve. Disconnect vacuum hose between the check valve and vacuum pipe at check valve side. Plug pipe end. Timing should not change for at least 1 minute. Stop engine and reconnect hoses.
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