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Test NS-2A: Checking Fuel System (Gasoline)

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Ensure throttle cable is not holding throttle open. Repair throttle cable as necessary and perform TEST VER-1A: NO START VERIFICATION . If throttle is okay, go to next step.
  2. On all bodies except AB body, go to next step. On AB body, use scan tool to read Vehicle Theft Security System (VTSS) status. If scan tool does not display FUEL ON, perform VTSS TEST in appropriate BODY CONTROL COMPUTER TESTS article in appropriate lemon-25® ELECTRICAL SERVICE & REPAIR manual. If scan tool displays FUEL ON, go to next step.
  3. On all bodies except TJ, XJ and ZJ bodies, go to next step. On TJ, XJ and ZJ bodies, disconnect fuel injector No. 1 connector. Using scan tool, actuate ASD relay. Using an external voltmeter, check voltage on fuel injector No. 1 connector, ASD relay output circuit (Dark Green/Black wire on TJ body; Dark Green/Orange wire on all other bodies). If voltage does not pulsate from zero to more than 10.5 volts, repair open ASD relay output circuit and perform TEST VER-1A: NO START VERIFICATION . If voltage pulsates as specified, go to next step.
  4. Using scan tool, select VTSS menu, then MONITORED DISPLAY. If scan tool displays ENGINE CONTROLLER OK TO RUN ENGINE, go to next step. If scan tool does not display ENGINE CONTROLLER OK TO RUN ENGINE, perform VTSS TEST in appropriate BODY CONTROL COMPUTER TESTS article in appropriate lemon-25® ELECTRICAL SERVICE & REPAIR manual.
  5. Using scan tool, actuate fuel system. Using a stethoscope, listen for fuel pump operation at fuel tank. If fuel pump operation cannot be heard, perform TEST NS-5A: CHECKING FUEL PUMP . If fuel pump operation can be heard, go to next step.
    WARNING: Fuel system may be under pressure. Release fuel pressure before connecting fuel pressure gauge. See FUEL PRESSURE RELEASE .
  6. Turn ignition off. Release fuel pressure. Ensure fuel tank is at least 1/4 full. Connect a fuel pressure gauge to fuel rail. Go to next step.
  7. Turn ignition on. Using scan tool, actuate fuel system. Read fuel pressure gauge. If fuel pressure is more than 54.2 psi (3.8 kg/cm2 ), replace fuel filter/regulator and primary fuel filter, and perform TEST VER-1A: NO START VERIFICATION . If fuel pressure is less than 44.2 psi (3.1 kg/cm2 ), perform TEST NS-4A: REPAIRING LOW FUEL PRESSURE . If fuel pressure is 44.2-54.2 psi (3.1-3.8 kg/cm2 ) and vehicle initially started and stalled repeatedly, perform TEST NS-8A. If vehicle did not initially start and stall repeatedly, go to next step.
  8. Using scan tool, actuate any fuel injector. Listen or feel for fuel injection operation. If injector is not operating, repair appropriate ASD relay output circuit (Dark Green/Pink wire on TJ body; Dark Green/Orange wire on all other bodies). Perform TEST VER-1A: NO START VERIFICATION . If injector is operating properly, perform TEST NS-3A: CHECKING ENGINE MECHANICAL SYSTEM .
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