Part 2 of 2

Chart A-7 - Fuel System Diagnosis (2 Of 2):

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.
1. Pressure less than 62 kPa (9 psi) falls into two areas:
- Regulated pressure under 62 kPa (9 psi). Amount of fuel to injectors OK but, pressure is too low. System will be lean and may set Code 44. Also, hard starting cold and poor overall performance.
- Restricted flow causing pressure drop. Normally, a vehicle with a fuel pressure of less than 62 kPa (9 psi) at idle will not be driveable. However, if the pressure drop occurs only while driving, the engine will normally surge then stop as pressure begins to drop rapidly.
2. Restricting the fuel return line allows the fuel pump to development its maximum pressure (dead head pressure). When battery voltage is applied to the fuel pump test terminal, pressure should from 90 to 124 kPa (13-18 psi).
3. This test determines if the high fuel pressure is due to a restricted fuel return line or a throttle body pressure regulator problem. Apply battery voltage to the fuel pump "test" connector only long enough to get an accurate fuel pressure reading.