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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 126 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING)FUEL SYSTEMSFUEL INJECTOR BALANCE TESTDIAGNOSTIC PROCEDURES
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8

Diagnostic Procedures

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Diagnose fuel injector low or high voltage circuit fault DTCs first. A circuit fault will cause an inoperative fuel injector.
  2. Install scan tool. Start engine. Using scan tool, command FUEL PUMP RELAY Off, until engine stall. Leave ignition on.
  3. Connect fuel pressure gauge to fuel line test port.
  4. Disconnect all 4 fuel injector harness connectors.
  5. Using scan tool, energize fuel pump to command FUEL PUMP RELAY On for 5 seconds, then command FUEL PUMP RELAY Off.
  6. Check fuel gauge reading. Ensure fuel rail pressure is 50-60 psi (345-414 kPa). If fuel pressure is not as specified, see FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L & 3.0L VUE.
  7. Connect Electronic Fuel Injector Tester (SA9182E) to harness connector of fuel injector to be tested.
  8. Using electronic fuel injector tester, pulse injector to be tested. Note fuel pressure at the instant the gauge needle stops.
    9. NOTE: Determine the most common pressure reading for all cylinders after each flow is performed. This will be the value used to determine if another injector is not working properly. All injectors should be within +/-1.5 psi from the most common reading.
  9. Repeat steps  5 -  8 .
  10. Disconnect electronic fuel injector tester.
  11. Reconnect all fuel injector harness connectors.
  12. Start and operate engine at idle, to clear raw fuel from cylinders.
  13. Using scan tool, relieve fuel pressure.
  14. Energize fuel pump.
  15. Using scan tool, perform fuel injector balance test.
  16. Ensure first fuel pressure reading is 50-60 psi (345-414 kPa).
  17. Record pressure the instant gauge needle stops moving (2nd reading).
  18. Repeat steps  6 -  8 for the remaining cylinders.
    19. NOTE: Engine must be started after testing 4 cylinders, to prevent flooding or internal damage.
  19. Add all the 2nd readings together and divide by 4 (2.2L engines) or divide by 6 (3.0L engines). This will be the 2nd reading average result.
  20. Subtract the average of 2nd reading from each 2nd reading to obtain the difference.
  21. If difference is greater than +/-1.5 psi, injector is faulty.
  22. Check that all injector connections are connected. Pull back on connector to check for positive engagement.
  23. Remove fuel gauge from fuel pressure test port and recap test port.
  24. Install air cleaner inlet tube.
  25. Start engine and check for leaks.
    26. NOTE: If engine is at operating temperature, allow a 10-minute cool down period.
  26. Diagnose any fuel injector low or high voltage circuit fault DTCs first. A circuit fault will cause an inoperative fuel injector.
  27. Using scan tool, relieve fuel pressure. Operate engine until it stalls. Leave ignition on.
  28. Connect fuel pressure gauge to fuel line test port.
  29. Using scan tool, command FUEL PUMP RELAY On for 5 seconds, then command FUEL PUMP RELAY Off.
  30. Ensure fuel rail pressure is 50-60 psi (345-414 kPa). If fuel pressure is not as specified, refer to FUEL SYSTEM DIAGNOSIS under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L & 3.0L VUE.
    31. NOTE: ECM will automatically energize fuel pump for one second between each different fuel injector flow test. ECM will allow 2 flow tests per injector, unless engine has been started and ran for longer than 5 seconds.
  31. Using scan tool, perform FUEL INJECTOR FLOW TEST for each individual injector. Note fuel pressure after each injector has been pulsed.
    32. NOTE: Determine the most common pressure reading for all cylinders after each flow is performed. This will be the value used to determine if another injector is not working properly. All injectors should be within +/-1.5 psi from the most common reading.
  32. Start and allow engine to operate in order to clear raw fuel from cylinders.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.