Gauge Calibration (Fuel)

[gav240z]

Hi everyone,

So a while ago I replaced my fuel gauge because the rear green plastic light filter was damaged due to a too bright light bulb, you can read more about it here.

http://www.viczcar.com/forum/index.php/topic,14206.msg161404.html#msg161404

 

1 thing I've noticed since it was replaced was that after I put a full tank of fuel in the car it only went up to 3/4 full. It's always been accurate but the new gauge seems to be less accurate and I'm not sure why?

 

Does anyone know if these can be adjusted and if so how? Or is there anything else I can check? I had the same problem in my 260z years ago and at the time I kinda bent the float down on the sender in the tank which would give me a better indication of when it was nearly empty.  But it never seemed like the correct fix. Did fuel tank designs change between models? Were different senders and resisters used? Or is there some adjustment in the gauge itself?

 

I came across this

http://zclub.net/forum/showthread.php?t=24466

 

and a few other articles but this seems to be a problem since I installed the new gauge. Weird..

[theremm]

I'm interested to know how to fix this. Mine only goes to 50% when full (although it did go all the way to 100% just once).

 

I have heard from a few people that this is a common problem.

[Scoota G]

Dale and i put a bit of thought into this some time ago. Take out the sender and it's much like a hand control for a slot car. A brass needle takes reading of wire wrapped around a flat surface right! Over time the tip of that needle flattens so it then contacts more wiresthan it would if it was new. Kinda makes sense it would give you an incorrect reading. Just a theory.

[Scoota G]

What do you peoples think?

[gav240z]

I haven't looked at my sender yet the car in question is in Melbourne, I will eventually but first wanted to ask questions so when  I do look at it I have a few ideas to experiment with.

[Linton]

as Scoot said, the only adjustment is the sender itself, you can bend the float arm only if it is reading under full, ( bending one way also alters the other side reading) as they wear the arm can lift away from the wire coil as well, causing a disconnect at a specific point. you need to remove and visually inspect, connect an ohm meter to the unit and watch it as you move the float arm in each direction,

 

if you earth out the connecting wire at the sender before removal have someone else turn on the ign and watch the gauge, the gauge should move to full this tests the gauge operation

[Zedman240®]

Linton is spot on; check the gauge by earthing the wire on to something metal near the tank first before you start pulling things apart!