System Pressure Test

1. Disconnect the fuel inlet line at the fuel injector rail.
2. Connect an appropriate fuel pressure gauge with a "T" fitting at the end of the inlet line.
3. Using an extension hose reconnect the fuel inlet to the fuel injector rail.
4. Disconnect the vacuum line at the fuel pressure regulator and plug the line.
5. Start the engine and observer the fuel pressure gauge.

With the engine idling the fuel pressure gauge should read between 40 - 47 psi. (2.8 - 3.2 bar).

6. Reconnect the vacuum line to the pressure regulator.

With the engine idling the fuel pressure gauge should indicate a drop of approx 5 psi. (0.35 bar).

^ If the fuel pressure does not drop when the vacuum line is reconnected and the vacuum line is not blocked or broken, a problem either with the pressure regulator or with fuel return is indicated.
^ If the fuel pressure is too low or does not increase with the vacuum line disconnected a fault is indicated with the fuel pressure regulator or fuel delivery.
^ If the fuel pressure is too high a problem with the pressure regulator or the fuel return is indicated.

HIGH FUEL PRESSURE

Fuel Volume Test:

1. Remove the fuel pressure regulator return line.
2. Attach a short hose to the pressure regulator outlet and direct it into an unbreakable container.

Fuel Pump Relay Diagram:

3. Remove the fuel pump relay and bridge terminals 6 and 2 of the fuel pump relay socket with a fused type switch.
4. Turn the switch (ON) and check the pressure.

The fuel pressure gauge should read 40 - 47 psi. (2.8 - 3.2 bar).

^ If the fuel pressure is too high the fuel pressure regulator if faulty.
^ If the fuel pressure is now correct the fuel return is blocked. Check for:
a. Improperly routed return lines
b. Pinched or crushed return lines
c. Faulty fuel tank inlet lines

LOW FUEL PRESSURE

1. Remove the fuel pump relay and bridge terminals 6 and 2 of the relay socket with a fused type switch.
2. With the switch (ON) pinch off the fuel pressure regulator return line. (This should be done slowly to avoid damage to the pressure gauge)

^ If the fuel pressure is 60 psi or above the fuel pressure regulator is faulty.
^ If the fuel pressure is not 60 psi or above there is a problem with fuel delivery. Continue with the fuel pump volume test.


FUEL PUMP VOLUME TEST

1. Disconnect the return line from the fuel pressure regulator and install a length of fuel line in its place.
2. Remove the fuel pump relay and bridge terminals 6 and 2 of the relay socket with a fused switch.

Fuel Volume Test:

3. Direct the fuel line into an unbreakable measuring container.
4. Turn the fused switch (ON) for 30 seconds.

^ Approx. 30 oz. of fuel should be delivered within a 30 second period. If the fuel volume is not correct check for:

a. Faulty fuel pump or pump pickup
b. Blocked fuel filter
c. Incorrectly routed or damaged fuel lines
d. Damaged or defective fuel tank