Mitsubishi 3000GT 1991 Service Manual page 244

FUEL SYSTEM - On-vehicle Inspection of MPI Components
TSB Revision
FUEL PRESSURE TEST
(1) Reduce the internal pressure of the fuel pipes and hoses.
(2) Disconnect the fuel high pressure hose at the delivery pipe
side.
Caution
Cover the hose connection with rags to prevent splash
of fuel that could be caused by some residual pressure
in the fuel pipe line.
adequate O-ring or gasket between the gauge end special
tool prevent fuel leaks.
between high pressure hose.
fuel pump and to the positive 0 terminal of the battery to
activate the fuel pump. With fuel pressure applied, check to
be sure that there is no fuel leakage from the fuel pressure
gauge and the special tool connection part.
(7) Disconnect the jumper wire (from the terminal for activation
of the fuel pump) to stop the fuel pump.
(8) Start the engine and let it idle.
(9) Measure the fuel pressure during idling.
Standard value:
<Non Turbo>
<Turbo>
Approx. 270 kPa (38 psi) at curb idle
Approx. 235 kPa (34 psi) at curb idle