Ford Mid-Size Cars 1971-1985 Repair Guide

Relieving Fuel System Pressure


Fuel supply lines on fuel injected vehicles will remain pressurized for some time after the engine is shut off. Fuel pressure must be relieved before servicing the fuel system.

As a safety feature, all electronic fuel injected engines are equipped with a pressure relief valve. On the 4-cylinder engine with Multi Port Fuel Injection (MPFI), this valve is located in the flexible fuel supply tube approximately 12 in. (30cm) back from where it connects to the engine fuel rail, on the driver's side of the engine compartment. On V8 equipped engines with MPFI, the valve is located in the metal fuel line at the left front corner of the engine.

Before opening the fuel system on a fuel injected vehicle, relieve the fuel pressure as follows:

  1. Disconnect the negative battery cable.
  3. Remove the fuel tank cap to relieve the pressure in the fuel tank.
  5. Remove the cap from the Schrader valve located on the fuel supply manifold.
  7. Attach fuel pressure gauge T80L-9974-A or equivalent, to the Schrader valve and drain fuel through the drain tube into a suitable container.
  9. After the fuel system pressure is relieved, remove the fuel pressure gauge and install the cap on the Schrader valve.