by looking at old posts i was able to remove and put in new sending unit, o ring and locking ring. 99% sure its all in correct. I am getting ready to attach wiring. Pretty sure the yellow wire with cap goes at top (one with small bit of rubber on stud). Also think the other cap, blackish/redish wire goes to bottom stud. 

Anyone have an clue what the other 2 wires are for? many thanks

 

 

 

 

huh....hooked up the wires and it move the fuel gauge 100% over to full....no way its full.. maybe 3 gallons in. 

Those are for a fuel pump.

 

The high fuel reading may be from the rod on the new sending unit not matching the bend of the previous, most likely the OE. I know you can touch those wires together and it will show FULL on the gauge. You may have them on the wrong terminals. The thread I linked above describes which one to what post. Hope it helps.

11 minutes ago, siteunseen said:

Those are for a fuel pump.

 

I know there is a mechanical fuel pump on but i think you are talking about an electric pump?

link is a big help. thanks. I have the old rod. will take new one out and match in up maybe tomorrow.

There is wiring in the 240Z for an electric fuel pump. In the center stack, there is a 2 pin T connector. One wire is black/white (ignition), and the other is green. The green goes out to the fuel pump. The intent was for the other part of the connector to be wired with an inline fuse to power the pump. However, if you ever get tempted to install an electric pump, I advise including an inertia switch inline with the fuse to cut power to the pump in the event of an accident.