Fuel Pressure: Testing and Inspection

1. Turn the key on and listen for fuel pump noise for 5 seconds.
a. If sound is heard, proceed to step 2.
b. If sound is not heard, perform fuel pump test. If fuel pump is O.K., proceed to Computers and Control Systems and check the fuel pump control circuit.

Fuel Pump Fuse:

2. Remove the fuel pump fuse from the fuse box (located under the L.H. side of the dash).
3. Start the engine and run until the engine stops.
4. Turn the key off and reinstall the fuse.
Fuel pressure is now released.

Fuel Pressure Gauge:

5. Disconnect the fuel inlet hose at the the injector rail.
6. Install a high-pressure fuel gauge (0 to 60 psi) between the hose and throttle chamber with a "T"-fitting.
7. Start the engine and check for leakage at the fittings.
8. Allow the engine to idle and observe the gauge reading.
a. If fuel pressure is 33.3 psi (226 kPa, 2.30 kg/cm2), fuel pressure is O.K.. END TEST.
b. If fuel pressure is below 33.3 psi (226 kPa, 2.30 kg/cm2), proceed to step 9.
c. If fuel pressure is above 33.3 psi (226 kPa, 2.30 kg/cm2), proceed to step 15.
9. Disconnect the fuel pressure regulator vacuum hose and check for vacuum at the fuel pressure regulator hose.
a. If vacuum does exist, proceed to step 10.
b. If vacuum does not exist, inspect the vacuum source and hose for proper routing and repair and replace as needed.
10. Observe the gauge readings.
a. If fuel pressure does not raise to 43 psi (294 kPa, 2.94 kg/cm2) after removing vacuum hose, replace the fuel pressure regulator and re-test.
b. If the fuel pressure does raise, inspect the fuel filter for restriction, if O.K. proceed to 11.
11. Remove the fuel cap and retest.
a. If O.K., replace the fuel cap and re-test.
b. If no change occurs, proceed to step 12.
12. Remove the fuel pump and inspect the pick-up screen for restriction.
a. If O.K. proceed to step 13.
b. If not O.K., clean the screen and re-test.
13. Inspect the fuel delivery lines for restrictions (kinks, bends or collapsed hoses).
a. If O.K. proceed to step 14.
b. If not O.K., repair or replace as needed and re-test.
14. Replace the fuel pump and re-test.
15. Disconnect the fuel pressure regulator vacuum hose and check for vacuum at the fuel pressure regulator hose.
a. If vacuum does exist, proceed to step 16.
b. If vacuum does not exist, inspect the throttle chamber for restriction and clean and replace as needed.
16. Observe gauge readings.
a. If fuel pressure does not raise after removing vacuum hose, replace the fuel pressure regulator and re-test.
b. If the fuel pressure does raise, proceed to step 17.
17. Inspect the fuel return lines for restrictions (kinks, bends or collapsed hoses).
a. If O.K. proceed to step 18.
b. If not O.K., repair or replace as needed and re-test.
18. Replace the fuel pump and re-test.