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Home >> GMC >> 2001 >> C3500 HD 6.5 F, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 6.5L - Troubleshooting >> Fuel System Diagnosis >> Fuel Lift Pump Flow Check
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Fuel Lift Pump Flow Check

  1. Install a scan tool.
  2. Disconnect the pipe at the lift pump outlet fitting.
  3. Install a hose at the lift pump outlet fitting and place a 1 liter (0.946 quart) container at the hose in order to collect fuel.
  4. Use the scan tool in order to command the lift pump ON and measure the amount of fuel.
    • If more than 0.24 liter (1/2 pint) in 15 seconds, refer to Fuel Lift Pump Pressure Check below.
    • If less than 0.24 liter (1/2 pint) in 15 seconds, refer to Fuel Lift Pump Suction Line Check below.