Dashpot System Check
- Connect tachometer to engine. Warm engine to normal operating temperature (cooling fan on). Disconnect vacuum hose from throttle control valve.
- Connect hand vacuum pump (except Civic models) to throttle control valve and apply 8 in. Hg vacuum. Check that engine speed rises (within 1 minute) to 1400-2000 RPM on Civic models.
- If speed was too low, or if speed was too high, loosen lock nut and turn adjusting nut.
- If speed cannot be adjusted, or diaphragm will not hold vacuum, replace the throttle control valve and retest.