Vacuum Test
- Start engine and warm to normal operating temperature (cooling fan comes on). Disconnect No. 6 vacuum hose from throttle controller and check engine speed. See Fig 1
. Engine speed should be 1700-2700 RPM for manual transmissions, and 1400-2400 RPM for automatic transmissions.
- If engine speed is excessively high, adjust engine speed by bending tab near bottom of throttle controller rod. If engine speed does not change, connect a vacuum gauge to No. 6 vacuum hose and check vacuum. If vacuum is present, replace throttle controller and retest. If vacuum is not present, check hose for proper connection, cracks, blockage or a disconnected hose. Replace and repair as necessary. Connect No. 6 vacuum hose and recheck idle speed.
Courtesy of AMERICAN HONDA MOTOR CO., INC.