Ensure battery is fully charged and ignition is in the "OFF" position. Relieve fuel system pressure and remove negative battery cable. Remove fuel supply-to-cold start injector banjo bolt.
Install Fuel System Adaptor (J-38347) with 2 new gaskets. Install fuel pressure gauge (J-34730-B). Ensure gauge is in the closed position. Install negative battery cable and turn ignition switch to the "ON" position.
Install jumper cable between the +B terminal and Fuel Pump terminal of check connector. See Fig 1 . Open gauge shut-off valve. Open gauge air-purge valve to bleed trapped air. Use a container to catch excess fuel that may be purged with air.
With fuel pump operating and engine off, fuel pressure should be 38-44 psi (2.7-3.0 kg/cm² ). Maximum fuel pressure (fuel line pinched) should be 57 psi (3.9 kg/cm² ). Start engine to measure fuel pressure with engine idling. Fuel pressure should be 30-33 psi (2.0-2.3 kg/cm² ).
If pressure is not within specification, check for defective fuel pump, pressure regulator or restriction in fuel system. Repair as necessary. Remove pressure gauge and start engine to ensure that no fuel leakage exists.

Fig 1: Prizm Fuel System Test Procedures

Courtesy of GENERAL MOTORS CORP.

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.

Safety Warning

Fuel Pressure Test (Prizm)