97 s14 fuel sending unit wiring question.

[Janz99]

Hey guys, hoping someone might be able to help me out on some wiring. I am in the middle of installing a PHR dual pump hanger on my 97 s14. In their instructions it mentions a 3 pin connector for the fuel sending unit but my car has a 4 pin and the color coding isnt the same. Does anyone know which 3 wires on the 97/98 are for the sending unit? I have grey, black, blue and white coming from inside the tank.

Thanks,
Ryan

[LoSt180]

I don't know the wire colors inside the tank off hand, but compare it to the wires on the car side connector. Checking the FSM shows:
Green - gauge cluster, fuel level
Red w/ Black stripe - gauge cluster, low fuel lamp
Blue - ECU, fuel tank temp sensor
Black - Ground

The fuel pump is the 2-pin connector, black w/ yellow stripe is power, black is ground. Again, don't know what the colors inside the tank are. Should be easy to match up though.

[Janz99]

Originally Posted by LoSt180

I don't know the wire colors inside the tank off hand, but compare it to the wires on the car side connector. Checking the FSM shows:
Green - gauge cluster, fuel level
Red w/ Black stripe - gauge cluster, low fuel lamp
Blue - ECU, fuel tank temp sensor
Black - Ground

The fuel pump is the 2-pin connector, black w/ yellow stripe is power, black is ground. Again, don't know what the colors inside the tank are. Should be easy to match up though.

What page did you find this on in the FSM?

I did find the testing procedure for the temp sensor in the FSM and from there figured out the blue was for the temp sensor.

Thanks for confirming!

[LoSt180]

The temp sensor was in the EC section, the gauge and warning light were both in the EL section.

I did notice an error in both the 97 and 98 manuals in that both the fuel level and the temp sensor say they are using pin #1 on the 4-pin connector at the bulkhead. So go by wire colors instead.

The FSM had the fuel level sensor on pin 1 & 4 (ground), the lamp on pins 3 & 4 (ground), but then has the temp sensor on pin 1 & 2. My guess is that the temp sensor is really on pin 2 & 4 (ground).

[Janz99]

Originally Posted by LoSt180

The temp sensor was in the EC section, the gauge and warning light were both in the EL section.

I did notice an error in both the 97 and 98 manuals in that both the fuel level and the temp sensor say they are using pin #1 on the 4-pin connector at the bulkhead. So go by wire colors instead.

The FSM had the fuel level sensor on pin 1 & 4 (ground), the lamp on pins 3 & 4 (ground), but then has the temp sensor on pin 1 & 2. My guess is that the temp sensor is really on pin 2 & 4 (ground).

I did notice the same thing which also caused some confusion on my end.

Thanks again for confirming the wiring!

-Ryan

[kennn]

Originally Posted by LoSt180

I did notice an error in both the 97 and 98 manuals in that both the fuel level and the temp sensor say they are using pin #1 on the 4-pin connector at the bulkhead. So go by wire colors instead.

The FSM had the fuel level sensor on pin 1 & 4 (ground), the lamp on pins 3 & 4 (ground), but then has the temp sensor on pin 1 & 2. My guess is that the temp sensor is really on pin 2 & 4 (ground).

Very astute.

FSM colours only apply on the body harness side up to the connector. Once you cross over into the component (fuel pump in this case), it changes to generic vendor colours (like all red, all green).

Go by wire colours and pin position on the body harness ONLY.

It's simple to bench test the pump assembly since you already have it out. The light switch has straight contact to ground when the float is at the bottom.

The fuel gauge sensor has variable resistance based on the position of the float.