Residual Pressure & Internal Leak Testing

Run engine and check fuel pressures as previously described. See SYSTEM PRESSURE TEST FUEL DELIVERY & SYSTEM PRESSURES - GASOLINE. Turn engine off and check residual pressure. Pressure should slowly drop below 41 psi (2.9 kg/cm² ) but should remain about 36 psi (2.53 kg/cm² ) for minimum 30 minutes. This is minimum pressure required to open fuel injectors. If pressure drops rapidly to zero psi, inspect check valve on fuel pump for bleed back or check for leaking injector.
If fuel pressure drops slowly to zero psi, disconnect fuel return line at diaphragm pressure regulator. There should be no flow of fuel, although slight see page is acceptable. Plug return line IMMEDIATELY if fuel flows heavily.
Pinch by-pass line to fuel inlet at fuel accumulator. If fuel pressure now holds with by-pass line pinched, replace fuel accumulator. If no leaks are found, remove cold start valve from manifold and check for it to leak under pressure. Replace start valve if it leaks.
After testing is completed, disconnect pressure gauge and clean any spilled fuel. Reconnect all fuel lines and tighten to 88-106 INCH lbs. (10-12 N.m). Start and run engine. Visually check all connections and lines for reassembly leaks.