Test NS-2A - Checking Fuel System

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For appropriate wiring diagram, see WIRING DIAGRAMS at end of article.

Turn ignition switch to ON position. Remove fuel tank filler cap. Using DRB-II, actuate fuel pump. Listen for fuel pump operation at fuel tank filler pipe. If fuel pump is not operating, go to TEST NS-3A.
If fuel pump is operating, turn ignition switch to OFF position. Disconnect fuel pump connector at fuel tank. Crank engine for 10 seconds. Turn ignition switch to OFF position.
WARNING: High fuel pressure may be present in fuel lines. Open fuel system carefully. See FUEL PRESSURE RELEASE .
Disconnect negative battery cable. Release fuel pressure. Connect fuel pressure gauge and adapter to fuel rail. Reconnect negative battery cable. Reconnect fuel tank connector at fuel tank.
Connect a jumper wire between positive battery terminal and fuel pump check terminal. See Fig 1 . Read fuel pressure gauge. If fuel pressure is more than 50 psi, go to step 6). If pressure is less than 47 psi, go to step 7). If pressure is 47-50 psi, disconnect jumper wire. Remove spark plugs, and inspect tips.

Fig 1: Identifying Fuel Pump Check Terminal (NS-2A)
If spark plug tips are wet with fuel, clean and dry spark plugs. Perform TEST VER-1. If spark plug tips are not wet with fuel, check for mechanical engine failure. Check valve timing and engine compression. Repair as necessary. Perform TEST VER-1.
Inspect for restricted fuel return line. Repair as required. Perform TEST VER-1. If fuel return line is not restricted, replace fuel pressure regulator. Perform TEST VER-1.
CAUTION: DO NOT allow fuel pressure to exceed 60 psi when squeezing fuel return hose.
Squeeze fuel return hose. If fuel pressure is more than 47 psi when fuel return hose is squeezed, replace fuel pressure regulator. Perform TEST VER-1.
If fuel pressure is less than 47 psi when fuel return hose is squeezed, remove jumper wire from fuel pump check terminal. Stop squeezing fuel return hose. Inspect fuel supply line for restriction.
If restriction exists in fuel supply line, repair as necessary. Perform TEST VER-1. If no restriction exists in fuel supply line, disconnect fuel pump electrical connector at fuel tank. Crank engine until fuel pressure gauge indicates zero psi.
Disconnect fuel filter. Inspect fuel filter for restriction. Replace fuel filter as required. Perform TEST VER-1. If fuel filter is not restricted, replace fuel pump. Perform TEST VER-1.