How to Performing a pressure test on a fuel pump

This is how to perform a pressure test on a fuel injected system. Look later on for an article on carburated systems.

Difficulty: Moderately Challenging

Instructions

1. Locate the fuel-pressure test fitting on the fuel line.

2. Connect fuel-pressure gauge to special fitting on the fuel line. This comes with an adapter.
   
   If system doesn't have special fittings and adapters can not be used, carefully remove any fuel-line connectors. When line is loosened, pressurized fuel will spray out of connections until pressure is relieved. Wrap a cloth rag around connectors.* A safer method is to disconnect the fuel pump so it can't operate. Check your service manual on how to disable fuel pump.* Remove relay that controls fuel pump, then fire the engine, let run a few seconds. It will stop when it runs out of fuel. Now safely remove fuel line connections.

3. Attach gauge, start engine. Compare reading on gauge with specifications in service manual.
   
   Pressure within spec' s- regulator is fine
   Pressure high- regulator needs replaced
   pressure low- regulator or pump is defective

Tips & Warnings

• In most cases the gauge can be attached directly to the fuel pump outlet. Then you can determine if the pump isn't producing enough pressure or the regulator is defective and not controlling the pressure in the system properly.