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Home › Jeep › 1998 › Cherokee Limited, 2.5 P › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes - Engine Performance › Self-Diagnostic Tests › Test NTC-5A: Checking Fuel Delivery

Test NTC-5A: Checking Fuel Delivery

WARNING: High fuel pressure may be present in fuel lines. Open fuel system with caution. See FUEL PRESSURE RELEASE .
  1. Inspect fuel lines for kinks or restrictions. Release fuel pressure and repair fuel lines as necessary, and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If no kinked or restricted lines exist, go to next step.
  2. Turn ignition off. Release fuel pressure. Connect fuel pressure gauge to fuel rail. See FUEL PRESSURE RELEASE . Turn ignition on. Go to next step.
  3. Using scan tool, actuate fuel system test. If fuel pressure is 44.2-54.2 psi (3.1-3.8 kg/cm2 ), fuel pressure is normal. Stop fuel actuation test. Test passed. If fuel pressure is not as specified, record fuel pressure reading and go to next step.
  4. On AB, TJ, XJ and ZJ bodies, go to next step. On all other bodies, stop fuel actuation test. Release fuel pressure. Replace fuel pump module and perform TEST VER-2A: ROAD TEST VERIFICATION .
  5. If fuel pressure is more than 54.2 psi (3.8 kg/cm2 ), fuel pump is okay, but internal fuel regulator is defective. Replace fuel pump module and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If fuel pressure is more than zero, but less than 44.2 psi (3.1 kg/cm2 ), check and repair kinked fuel supply line between fuel rail and fuel pump module and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If no kink exists, go to next step.
  6. Release fuel pressure. Disconnect fuel supply line at fuel rail. Connect appropriate fuel line pressure hose into disconnected supply line. Insert other end of hose into a graduated container. Remove fuel cap and go to next step.
    CAUTION: DO NOT actuate fuel system for more than 7 seconds in following step.
  7. Using scan tool, actuate fuel system for 7 seconds. A good fuel pump will deliver at least one quart of fuel into container. If fuel delivery is as specified, go to step 10)  . If fuel delivery is not as specified, go to next step.
  8. If fuel pump can be heard operating through fuel cap opening, check and repair kinked fuel supply line between fuel rail and fuel pump module and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If no kink exists, go to next step.
  9. If fuel pressure is low but delivery is okay, replace fuel filter/regulator and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If both fuel pressure and fuel delivery are low, replace fuel pump module and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies.
  10. Disconnect fuel supply line at fuel rail. Connect appropriate fuel line pressure hose between disconnected supply line and fuel rail. Connect fuel pressure test gauge to fuel line pressure hose. Start engine and allow it to reach normal operating temperature. Go to next step.
  11. Observe test gauge. Normal operating pressure should be 44.2-54.2 (3.1-3.8 kg/cm2 ). Turn engine off. Pressure should hold at more than 30 psi (2.3 kg/cm2 ) for 5 minutes. If pressure is not as specified, check fuel injectors, fuel pump module or a fuel tube or line for leaks. Repair as necessary and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If pressure is as specified, go to next step.
    NOTE: Steps 12)-15) require the use of Chrysler's DRB-III scan tool and Low Current Shunt (LCS) adapter.
  12. Connect LCS adapter to scan tool SET 1 receptacle. Connect test leads to LCS 10A and (-) receptacles. Using scan tool, access MAIN MENU. Press DVOM button on scan tool. Using LEFT/RIGHT arrow keys, select CHANNEL 1. Press ENTER 3 times. Go to next step.
    CAUTION: The following step must be performed to prevent damage to scan tool or LCS adapter.
  13. Using UP/DOWN arrow keys, select RANGE. Scan tool will default to 2-amp scale. Press ENTER to change scan tool to 10-amp scale. Go to next step.
  14. Remove cover from Power Distribution Center (PDC). Remove fuel pump relay. Relays are identified on label under PDC cover. Go to next step.
    CAUTION: Ensure all fuel line and fuel system components are connected. Fuel pump will activate in following step.
  15. Using scan tool, read fuel pump amperage. Attach test leads from LCS adapter to fuel pump relay connector terminals No. 30 and 87 on type-1 and type-2 relays, or terminals No. 3 and 5 on type-3 relay. See Fig 1, Fig 2 or Fig 3 . Disconnect test leads from fuel pump relay connector. Go to next step.
  16. If amperage is more than 10 amps while test leads are connected, release fuel pressure. Replace fuel pump module and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body or test TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If amperage is 10 amps or less while test leads are connected, go to next step.
  17. Check for contaminated fuel (such as water in fuel). If fuel is contaminated, drain and fill with known-good fuel and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES  on AB body, or TEST VER-2A: ROAD TEST VERIFICATION  on all other bodies. If fuel is not contaminated, fuel system is okay at this time. Test passed.
Fig 1: NTC-5A1: Identifying Type-1 Fuel Relay
G98F00922
Fig 2: NTC-5A2: Identifying Type-2 Fuel Relay
G98J00090
Fig 3: NTC-5A3: Identifying Type-3 Fuel Relay
G98G00923
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