Power Valve
- With engine warm, disconnect hose from power valve and connect a vacuum pump. Operate vacuum pump and ensure vacuum remains steady. If not, replace power valve diaphragm.
- Start engine. Vacuum should be present at idle. If vacuum is present, got to next step. If there is no vacuum, check for voltage at the lock solenoid. If there no voltage, check and repair wiring, fuse or connections.
- Check for vacuum between the power valve control solenoid valve and lock solenoid valve. If present, replace lock solenoid and retest. If there is no vacuum, check for voltage at power valve control solenoid valve.
- If voltage is present, replace power valve control solenoid and retest. If there is no voltage, go to steps 6) thru 14) in IDLE BOOST CONTROL, COLD ENGINE section in this article.
- Turn ignition off. Ensure vacuum remains steady. If not, replace the lock solenoid valve and retest. Remove the No. 1 control box cover. Pinch hose connected to vacuum switch "A".
- Disconnect the upper tube from lock solenoid valve and connect a hand vacuum pump. Operate engine above 3000 RPM. No vacuum should be present. If present, check for voltage at power valve control solenoid valve.
- If voltage is present, go to steps 6) thru 14) in IDLE BOOST CONTROL, COLD ENGINE section in this article. If no voltage is found, replace the power valve control solenoid valve and retest.