Test NS-4A - Checking Fuel Delivery
WARNING:
High fuel pressure may be present in fuel lines. Open fuel system with caution. See FUEL PRESSURE RELEASE
procedure in this article.
NOTE:
For connector terminal identification, see CONNECTOR IDENTIFICATION
. For appropriate wiring diagram, see WIRING DIAGRAMS
at end of article.
- Record fuel pressure gauge. Turn ignition switch to OFF position. Release fuel pressure. Remove fuel pressure gauge. Install fuel pressure gauge between fuel tank and fuel filter. Reconnect previously disconnected fuel line.
- Turn ignition switch to ON position. Using DRB-II, actuate fuel system. Record fuel pressure gauge. Compare fuel pressure gauge reading with previous reading.
- If fuel pressure is at least 10 psi more than previous reading, inspect fuel lines between fuel filter and fuel rail for restrictions. Repair as required. Perform VERIFICATION PROCEDURE VER-1. If no restrictions exist, replace fuel filter. Perform VERIFICATION PROCEDURE VER-1.CAUTION: DO NOT allow fuel pressure to exceed 70 psi when squeezing fuel return hose.
- If fuel pressure is not at least 10 psi more than previous reading, gently squeeze fuel return hose while watching fuel pressure gauge. If fuel pressure exceeds 38 psi, replace fuel pressure regulator. Perform VERIFICATION PROCEDURE VER-1.
- If fuel pressure does not exceed 38 psi, replace fuel pump and filter sock. Perform VERIFICATION PROCEDURE VER-1.