Fuel System Pressure Test
- Connect pressure gauge (0-300 psi) to service port on fuel injector rail. Start engine and monitor fuel pressure.
- Minimum operating pressure is 90 psi, and maximum operating pressure is 140 psi. Operating pressures can be affected by:
- Outside ambient temperature.
- Low-pressure fuel shutoff solenoid condition.
- Fuel injector(s) condition.
- High-pressure fuel shutoff solenoid and solenoid relay condition.
- Engine load requirements.
- If fuel pressure is more than 140 psi (fuel tanks 1/8 full-minimum), replace fuel pressure regulator. See REMOVE/INSTALL/OVERHAUL - 3.3L CNG article in the ENGINE PERFORMANCE section.
- If fuel pressure is less than 90 psi, ensure all fuel cylinders have sufficient fuel level (1/8 or more). Ensure manual shutoff valve and all fuel control valves are fully open. Inspect fuel tubes for kinks and restrictions.
- Inspect and test low-pressure fuel shutoff solenoid, high-pressure fuel shutoff solenoid and fuel injectors. See SYSTEM/COMPONENT TESTS - 3.3L CNG article in the ENGINE PERFORMANCE section. Inspect fuel system for leaks. See LEAK TESTING . Remove fuel pressure gauge. On Ram Van/Wagon, install air cleaner assembly and engine cover.