Tips for test fuel pressure systems

Determine a plan of action for foreign and domestic models when testing fuel pressure.

Connecting to most Nissan, Mazda and Mitsubishi models requires the same type of series connection. First, locate the fuel filter in the engine compartment. Then, disconnect the outlet line and connect a tee fitting between the outlet line and the fuel filter. Connect your gauge and take your readings.


European imports with Bosch K-Jetronic or KE-Jetronic fuel injection differ slightly from electronic injection for connection and testing. Since these systems operate at higher pressures than most electronic systems, make sure your gauge reads a maximum of at least 630 kPa (90 psi). You also need a special adapter hose with shut-off valve and some other small adapters to connect to various makes of cars.

Tee into the control pressure line with the adapter. The control pressure line connects the fuel distributor and the control pressure regulator.


After you're done testing and you've fixed what needed fixing, restore the injection system to its normal operating status. This also means tightening the lines and fittings to their proper torque values.

If any of the fittings use sealing washers, replace them. Installing the fittings without new sealing washers is like asking for a disaster.

Once everything's together, start the engine and check all fittings and connections for leaks. Then, and only then, release the car to the customer.

Okay, maybe it’s a little more trouble to tap into fuel injection systems from overseas, but it’s no big deal once you get the hang of it. With a little experience, it’ll ensure safety while shaving diagnostic time in the process.

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