98 Puma fuel gauge

[mihalyn90]

Hello guys,


So a little time before, I learned that my fuel gauge is idiot. It works, no problem, but what kills me is that if i turn off the ignition, remove the key, (flip the car, wash my teeth, have coitus or whatever) the fuel gauge is still reading... reading correct of course, but reading even with the ignition off...

Yes it's the old style Puma I know, but can i do something with this gauge? can I change it? add a little coil to move the damn indicator to zero?

Ideas pleaaaaaaase

I usually have full gas, so when i leave the car overnight in stranger places... i don't do it really happy...

 

[red]

Is this just not how it is on the older analogue?

It really isn't worth the effort to change to the digital dash from what I've read.

 

[mihalyn90]

Yes it is how it is on the old analog one... my electrician said it happens on a lot of cars... the gauge being resistance based, it doesn't move to zero...

Now the problem as i see it... if it is resistance based...

when i cut the power it stucks on the actual level...

fill to top... the gauge still showing the old level... giving an ignition and the damn thing raises to max...

My question, it is possible to get a spring loaded gauge so when i cut the power, it pulls it to zero?

 

[Ian G]

You could interrupt the reading to the sensor.

Four wires going to the fuel pump, 12v live, ground and two for the level sensor.

12v live is only present when the engine runs, so if you cut the level sensor wires and put them on the high side of a relay you could then use the 12v live to switch the relay.

That way when the pump stopped, the gauge level would effectively be disconnected.

Might need testing first as high resistance (the wire being cut) may be a full tank on the dashboard? Not sure. If its the other way around and high resistance is an empty tank then you're OK.

If you want to check, get under the seat and cut one of the thinner wires, fuel gauge will either rise or fall....

Or if you want me to do it, wait until an analogue car comes in and I'll do the testing myself!

 

[Ian G]

Incidentally the later cars are also resistance based. Perhaps they have some sort of interrupt as above in the standard wiring, not sure.

Either way you just want the empty tank condition on ignition off, which is not impossible to do electrically.

 

[mihalyn90]

Ian G, our dearest friend and puma lover just as we are, please enlighten me with some info if you can