LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1999 >> Forward Control 4.3 W, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Component Tests >> Emission Systems & Sub-Systems (Diesel) >> Vacuum Pump

Vacuum Pump

Connect vacuum gauge to vacuum pump inlet (small fitting). DO NOT plug or disconnect outlet fitting. With engine idling, vacuum should be 18 in. Hg one minute after start. If vacuum is not as specified, check for belt slippage, vacuum leaks or other obvious defects. If no defects are present, replace vacuum pump.