Troubleshooting 1995-98 S14 Fuel Pump/Relay Issues

Originally posted on January 1, 2013 by Roman Taylor.

This should help you diagnose fuel issues on your Nissan 240SX. Use at your own risk, and make sure you have a multimeter (along with other common tools) before attempting this.

Three main failure points:

• Fuel Pump
• Fuel Pump Relay
• ECU

Fuel Pump Plug:

Few things you can check for here:

• First check for 12V at the plug with key in the ON position, if you’re getting 12V -> fuel pump is likely bad
• Check for continuity between plug terminal B (the one with black wire going to it) and chassis
• Check for continuity between plug terminal A and Pin 5 on your Fuel Pump Relay

Fuel Pump Relay Location (Driver Side Kick Panel):

You’ll see another blue and black relays next to it under driver side kick panel, it’s the one that has four black wires going to it. Simple test you can do before taking out the relay, is to hold it in your hand and turn the key into ON position without starting the car – if they relay is good, you should feel it click

Fuel Pump Relay Plug and Fuse:

Don’t forget to check your fuse if you haven’t already done so.

• Pin #1 gets power from Ignition Switch, so you should see 12V with key in the ON position
• Pin #2 is ground signal from ECU, it can be verified by checking for continuity between Pin #2 and a ground point while key is in the ON position (it will only work for couple seconds after turning the key)
• Pin #3 is power source from battery. It is wired to your 15 AMP Fuel Pump Fuse
• Pin #5 supplies power to your fuel pump so it should have continuity to Pin A on your fuel pump plug

Bench checking your relay:

Hook up Pin 1 and 2 to your battery (doesn’t matter which one goes to positive or negative).

Use your multimeter to check for continuity between Pin 3 and 5 – should have continuity with power applied.

Hope this helps!