EF Civic And DA Integra Fuel Level Sender Interchangeability

While swapping other parts from my DA Integra to my EF Civic I was curious if the fuel level senders are interchangeable, as the one in the Civic did not seem to work properly. Turns out, the senders are not interchangeable.

The two senders have different designs:

Here is a close-up of the bottoms of the sender caps. The EF sender has its gasket under (below) the cap, whereas the DA sender has its gasket around the cap. I decided to reuse the EF gasket; if I was reinstalling the DA sender I would have needed to get a new gasket.

The reason the senders do not interchange though is that the DA sender is made for a much larger hole than the EF sender:

You can also see that I cleaned the EF ring and not so much the DA ring.

Finally, the senders have different wiring. The EF sender has two wires going to it via a 2 pin connector. The DA sender has three wires going to it via a 4 pin connector. The additional connector in the DA fuel sender is for the low fuel level sensor - this sensor turns on the low fuel light on the dash. EF has no such light and, consequently, no associated sensor.

Electrically, the senders appear to expect different voltage as well. The EF sender expects battery voltage on input, while the DA sender expects 5-8 volts.