Mitsubishi Stealth 1994 Import Service Manual page 688

MULTIPORT FUEL INJECTION -
Condition
Fuel pressure is too low.
l
Fuel pressure drops during
l
racing.
No fuel pressure in fuel return
l
hose.
Fuel pressure is too high.
No change of the fuel pressure
when the vacuum hose is connected clogging.
and when not connected.
On-Vehicle Inspection of MFI Components
(9) Disconnect the vacuum hose from the fuel pressure
regulator, and then measure the fuel pressure while using a
finger to plug the end of the hose.
Standard value:
not decrease even after the engine is raced a few times.
repeatedly racing the engine, and check to be sure that
there is fuel pressure in the return hose also.
NOTE
There will be no fuel pressure in the return hose if there is
insufficient fuel flow.
from the standard value range, check for the probable
cause by referring to the table below, and then make the
appropriate repair.
Probable cause
Fuel filter is clogged.
Malfunction of the valve seat within
the fuel pressure regulator, or fuel
leakage to return side caused by
spring deterioration.
Fuel pump low discharge pressure.
The valve within the fuel pressure
regulator is sticking.
Clogging of the fuel return hose and/
or the pipe.
Damaged vacuum hose or nipple
Malfunction of the fuel pressure control
system <Turbo>
295 - 315 kPa (43 - 45 psi) at curb idle
Remedy
Replace the fuel filter.
Replace the fuel pressure regulator.
Replace the fuel pump.
Replace the fuel pressure regulator.
Clean or replace the hose and/or
pipe.
Replace the vacuum hose, or clean
the nipple.
Checking the fuel pressure control
system <Turbo>