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Step 11 - After the gauge hose has been removed, install the fitting dust cap.

Reinstalling Dust Cap

Step 12 - Using a clean shop towel wipe the area free of fuel. Once testing is complete, inspect the area for fuel leaks.

Clean Area

Helpful Information

Some vehicles are not designed with a fuel pressure test port, in which case a fuel filter adapter must be used for the gauge connection.

A fuel pressure regulator is controlled by a diaphragm and spring combination in conjunction with intake manifold vacuum. When a fuel pressure regulator diaphragm ruptures, it allows raw fuel to enter the vacuum feed line and into the engine. This condition creates a rich black smoke from the tail pipe on start up and while running. Remove the vacuum line from the regulator, if fuel is present, the regulator has failed.

Some GM (CPI Injection) are designed with an internal regulator in which the intake manifold must be removed to access..

Best Practices

• Replace pressure regulator with quality replacement parts or premature failure could occur.