Vacuum Control Valve
- Ensure engine is at operating temperature. Disconnect and plug the hose number 31 from the vacuum control valve. See Fig 1 .
- Disconnect the vacuum hose from vacuum control valve to air control valve A. Install a vacuum gauge to the vacuum control valve.
- Start engine and run at idle speed. If there is no vacuum, go to step 4). If vacuum is present, check hose number 15 for blockage, leaks or proper routing. If no problem found, replace vacuum control valve and retest.
- Raise engine speed to 3500 RPM. Watch vacuum gauge and close throttle suddenly. If vacuum appears momentarily, vacuum control valve is okay. If not, check vacuum hoses number 15 and 19 (to intake manifold) for blockage, leaks or proper connections. If no problem is found, replace the vacuum control valve and retest.