TM 9-2815-225-34&P 3-63.  FUEL PUMP TESTING AND CALIBRATION (Contd) LOCATION/ITEM ACTION REMARKS f.  Fuel Pump Vacuum 50. Bypass valve (35) Close. 51. Suction control valve (77) Open completely. 52. Fast button (25) Depress until fuel pump speed is 2000 rpm. 53. Suction control valve (77) Adjust to obtain exactly 8.00 Once this suction control valve in. Hg.  (28,800 kPa) reading setting is attained, it must not be on No. 2 vacuum gauge (3) at changed during later calibration 2000 rpm pump speed. procedures. 3-486