Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Pressure
Basic diagnosis of fuel system should begin with determining fuel system pressure. If fuel pump is inoperative, check fuel pump fuse in fuse panel. If fuse is okay, see FUEL SYSTEM in I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section for specific circuit or wire color reference.
- To relieve fuel system pressure, remove fuel pump fuse (fuel pump relay on 300ZX). Start engine and allow to run until engine stalls. Crank engine an additional 2 or 3 times to verify all pressure has dissipated. Turn ignition off. Install fuel pump fuse or relay.
- Connect fuel gauge between fuel filter outlet and fuel tube using a "T" connector. To prevent inaccurate fuel pressure readings, disconnect electrical connector at fuel pressure regulator control solenoid valve (if equipped). Start engine. Check fuel line connections for leaks.
- Check fuel pressure on pressure gauge with engine idling. Disconnect vacuum hose from pressure regulator and recheck fuel pressure. Compare fuel pressure readings on pressure gauge with specifications in FUEL PRESSURE table.
- Release fuel system pressure as described in step 1). Disconnect fuel pressure gauge. Reconnect fuel lines. Start engine and check for fuel leaks. If necessary, clear trouble Code 22 from ECU memory.
| Application | Unregulated - w/o Vacuum | Regulated - w/ Vacuum | |
|---|---|---|---|
| Maxima | 44 (3.1) | 36 (2.5) | |
| NX & Sentra | |||
| 1.6L & 2.0L | 43 (3.0) | 36 (2.5) | |
| Pathfinder & Pickup | |||
| 4-Cylinder | 43 (3.0) | 33 (2.3) | |
| V6 | 43 (3.0) | 34 (2.4) | |
| Stanza | 43 (3.0) | 33 (2.3) | |
| 240SX | 43 (3.0) | 34 (2.4) | |
| 300ZX | 43 (3.0) | 36 (2.5) | |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.