This is probably a stupid easy question for you guys.  But I'm new to owning a 280z.  I have a 78 by the way.  My question is I'm unfamiliar with how the gas gauge is supposed to operate.  I know it's a float unit and I've never owned a car with one before.  Mine for example right now is on just above slightly a half a tank.  But while I'm driving or even sitting still it moves a little, not much, just sometimes it's a half, then maybe a few seconds later it's just above a half slightly where it finally rests.  When I drive it seems to go up when I stop etc.  Is this normal, and due to the float, or should the gauge be still always and not have a lot of movement.??  

I know it's a dumb question but if your share some insight into what's "normal" operation for a 280z fuel gauge I would really appreciate it.

 

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The tank uses a float attached to a long lever which drives what basically is a variable resistor. The gauge uses resistance to ground to estimate fuel level. I'm not and expert on this. Hope someone can answer your question.


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My '77 stays pretty stable while driving.  Here's a couple of things to look at that'll help understand the way they work.

Open the hatch and you'll find the round cover that's over the sending unit.  If you touch the two wires together the gauge should go to EMPTY.  EDIT!!! maybe FULL, can't remember. 

 

Edited April 17, 20177 yr by siteunseen

On my 77 I get the needle fluctuation. Especially during long wide turns on the freeway. Been like that since I bought the car. Doesn't move much. More so when it's about half a tank.

Edited April 18, 20177 yr by rcb280z

Site, is that a new sending unit?

10 hours ago, rcb280z said:

Site, is that a new sending unit?

Yes Sir, shiny and clean but for a 240.  I don't know if the 280's are still available but the 240's are.  Seems like I paid $47, plus the 0-ring it was all $50.

I guess I don't drive as hard as you guys, I can't remember my needle moving while I'm driving. 

I do keep a full tank though.  Lesson learned from my earlier days. 

I believe the early 280's sender (side mount) is NLA and was considerably more when it was available. Used ones can be found and resurrected!

 

The 280 senders (side mount) have an "empty" sensor and an extra wire for that. Little red light on the fuel gauge will light up. Other than that they are identical (other than the connector) to the 240 senders if you need one and can't find a 280 sender.

Edited April 18, 20177 yr by zKars

The 280 senders (side mount) have an "empty" sensor and an extra wire for that. Little red light on the fuel gauge will light up. Other than that they are identical (other than the connector) to the 240 senders if you need one and can't find a 280 sender.

This is true! You could build a new one out of a 240 sender! 280 one below...

Interesting, good info guys!