Fuel Pressure

NOTE: Constant fuel pressure is maintained in fuel lines and component parts at all times. Relieve pressure before attempting to open system 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.

To release fuel system pressure on 300ZX and 300ZX Turbo models, start engine and unplug Blue fuel pump electrical connector in luggage compartment. On 200SX and 200SX Turbo models, unplug fuel pump connector in right rear tool box. After engine stalls, crank engine 2 or 3 times. Turn ignition off. Connect fuel pump electrical connector.
On Maxima models, start engine, disconnect fuel pump relay. Fuel pump relay is located on the right front fender. After engine stalls, crank engine 2 or 3 times. Turn ignition off. Connect No. 2 fuel pump relay.
Remove fuel filter-to-fuel rail hose and connect a pressure gauge using a "T" fitting. Start engine and read fuel pressure at idle. If pressure is not as specified, replace pressure regulator and repeat test.
Disconnect vacuum line from fuel pressure regulator and connect a hand vacuum pump. On 200SX and 300ZX and Turbo models, disconnect the fuel pump connector and apply battery power. On Maxima models, remove fuel pump relay and place jumper wire between Light Green/Red and Black/White wire in harness connector. Turn ignition on.
On all models, as vacuum is applied to pressure regulator, pressure reading should decrease. See FUEL PRESSURE SPECIFICATIONS table. If pressure and vacuum readings do not meet specifications, replace fuel pressure regulator.

FUEL PRESSURE SPECIFICATIONS

Condition: In. Hg

Pressure: psi (kg/cm² )

Idle ⁽¹⁾

30 (2.1)

36-37 (2.5-2.6)

33-35 (2.3-2.5)

31-32 (2.2-2.3)

29-30 (2.0-2.1)

26-28 (1.8-2.0)

⁽¹⁾	Vacuum hose connected at pressure regulator.