Fuel Line Pressure
CAUTION:
The Bosch LH Jetronic fuel injection system maintains constant fuel pressure in the fuel lines and component parts at all times. Be sure to relieve pressure before attempting to open system at any point for testing. DO NOT allow fuel to flow onto engine or electrical parts or allow an open flame in area while testing fuel system components.
- Connect a fuel pressure gauge between fuel line and injection manifold. Switch on ignition to activate fuel pump. Fuel pressure should be 35.5 psi (2.5 kg/cm2
).CAUTION: DO NOT let pressure exceed 85.2 psi (6.0 kg/cm2 ).
- If pressure is too low, pinch off fuel return line by hand and check if pressure rises. If pressure quickly rises pump and lines are functioning correctly. Replace pressure regulator and measure pressure.
- If pressure rises slowly, fuel filter, tank pump filter or lines are blocked. If pressure does not rise, pump is defective.
- If fuel pressure is high, disconnect fuel return line from pressure regulator and blow in line. If line is open pressure regulator is defective and should be replaced.
- Pressure may also be checked with engine off and fuel gauge connected. Attach a hand vacuum pump to pressure regulator. Line pressure should decrease as regulator is evacuated.