Power Valve Control Solenoid & Check Valve
- Check connecting vacuum hoses for leaks and obstructions. Repair as necessary. Remove hose from power valve at carburetor. With ignition key off, connect vacuum pump to hose and draw vacuum. Vacuum should remain steady. If not, replace check valve and retest.
- Turn ignition key on and vacuum should drop. If not, warm engine to normal operating temperature and check that there is vacuum at hose with engine running. If there is vacuum, proceed to step 4). If there is no vacuum, check voltage at power valve control solenoid valve in emission control box. Connect the negative lead of voltmeter to ground and connect the positive lead to Green/Blue wire at control box connector. See Fig 1 . If there is voltage, check control unit.
- If there is no voltage at power valve control solenoid valve, remove hose from inlet side of check valve and check vacuum. If there is vacuum, test check valve operation. If check valve tests OK, replace power valve solenoid control valve and retest. If there is no vacuum, check connecting hoses for leaks and obstructions.
- With vacuum gauge connected to hose removed from power valve, ground Red wire of control unit and check that vacuum drops to zero. If vacuum drops, system is OK. If vacuum does not drop, check voltage at power valve control solenoid in control box. See Fig 1 . Connect negative lead of voltmeter to ground and connect positive lead to Green/Blue wire at control box connector.
- If there is no voltage, check control unit. If there is voltage, replace power valve control solenoid valve and retest.