MPFI Models
- Remove cap from pressure test port in fuel rail. Connect fuel pressure gauge (J-34730-1) or equivalent to pressure fitting. Start vehicle. Pressure should be approximately 31 psi (2.17 kg/cm2 ) with vacuum hose connected to pressure regulator.
- Pressure should be 39 psi (2.74 kg/cm2 ) with vacuum hose removed from regulator. If fuel pressure is not to specifications, check for kinks or restricting bends in fuel supply and return lines. Check fuel pump flow rate. Pump should deliver a minimum of 1.06 quarts (one liter) of fuel per minute with fuel return line pinched off.
- If flow is inadequate, check system for plugged fuel filter or filter sock. Fuel pump flow rate can be checked by connecting a hose to fuel test port on fuel rail and inserting other end in clean container.
- To operate fuel pump, install a jumper wire into diagnostic connector terminals D1-5 and D1-6. Pinch off fuel return line to ensure that no fuel returns to fuel tank. If fuel pressure is still not to specifications and fuel flow is normal, replace regulator.