With fuel pressure relieved, remove air cleaner and gasket. Remove flexible steel fuel line between throttle body and fuel filter. When removing fuel line, always use 2 wrenches to prevent damage. Install fuel pressure gauge between throttle body and fuel filter.
Start vehicle and observe fuel pressure reading. Fuel pressure should be 9-13 psi (.6-.9 kg/cm² ). If pressure is within specification, go to next step. If fuel pressure is not within specification, refer to DIAGNOSTIC CHARTS, CHARTS A-5 and A-7, at end of article.
Release fuel pressure. See FUEL PRESSURE RELEASE. Remove fuel pressure gauge. To check fuel pump volume, insert end of fuel line into a container. Apply battery voltage to terminal "G" of the ALDL test connector. See Fig 1 .
Fuel pump should supply at least 1.0 pt. (.8 L) in 30 seconds. If fuel flow is less than specified, check for restricted fuel line. If fuel line is okay, replace fuel pump. Install steel flex line between fuel filter and throttle body. Start engine, and check for leaks. Install air cleaner and gasket.

Fig 1: Identifying ALDL Test Connector Terminals

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

Checking Fuel Pressure