Troubleshooting 1995-98 S14 Fuel Pump/Relay Issues
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
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!
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