Fuel Needle Stuck

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Marv

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Hey guys,

I had some issues with my fuel indication, so I removed the
tank and got the sending unit out. I cleaned it from the inside
and now it shows perfect values when testing the resistance.
While working on that, I switched on the ignition and the tank
needle, went up, up, passed FULL and left the display... :mad:
now it´s gone and I can´t get it back, even when I reinstall
the sending unit, set it on empty and start the engine ...

I don´t know how to get it back, so can somebody help me ?!?!

Thx Marv
 
have you tried to ground out the wire that comes from the sending unit to see if it returns to the full mark with the key on engine off?
 
do you have a full tank of gas?
as stated above remove the wire from the sending unit that goes to the gauge and connect it to any piece of metal, the frame, to see if that forces the needle back down to empty. Less resistance equals lower reading.

Elektrische Masse
______________________________
 
melsg5 said:
do you have a full tank of gas?
as stated above remove the wire from the sending unit that goes to the gauge and connect it to any piece of metal, the frame, to see if that forces the needle back down to empty. Less resistance equals lower reading.

Elektrische Masse
Click to expand...

Couldn't have answered the question better if I tried.
 
ahh ok thank you, I´ll try that, at the moment the tank is removed,
I just connected the sending unit again with the gauge, when I move
the float up and down it should have the same effect to the gauge.. if the
needle would be there :D
 
the sender has to be grounded if your are doing that. Anytime you work on a gas tank I recommend the battery should be disconnected.
 
no change, the needle is still lost ..
any other ideas ?!
if not I´ll just leave it as it is, I don´t see the point in
removing the dashboard just because of a *#!"ing needle
______________________________
 
the needle should go to zero with the sending unit power wire connected and the sending unit ground wire connected to a frame component with the car battery connected. Have you tested the sending unit power wire with a test light or volt meter?
 
yes I did and there are 5 Volts on it... and it was working before, but not quite
right, sometimes the tank was empty when the gauge showd half full, next time
I went to the gas station when the gauge was on half and just 6 gallons went in..
that´s why I removed the tank and checked the sending unit...

I´m afraid that it broke down when ignition was turned on without the ground wire
connected :-/ but the strange thing is, that if it would have been too much power,
the fuse should have been blown... shouldn´t it ?!?!
 
It's normal for the needle to go to full without the ground connected. Have you tried gently tapping on the gauge with the sender fully connected and the float all the way down?
 
yes .. not only gentle ^^

I tried it with ingnition on, with engine turned on
powerwire grounded with ignition and engine
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At this point I one would think the gauge may be the problem or a burnt circuit path behind the gauges or even a bad voltage regulator that controls the gauge.
You shouldn't have to remove the entire dash just the gauge cluster.
 
Thank you for the link, I´m going to check this... In the meanwhile
I´m convinced that the 5 volt regulator probably just quitted ...
So do you have picture how this little box looks like ? There´s not
much space behind the dash I´m not sure if I already discovered it the
last time I looked behind it
 
Hi sorry it took so long to get back to you, First off if the regulator is bad or not working, all of your gauges would not be working.
However here is a link to what it should look like. your regulator may differ slightly.
https://youtu.be/9Zmq965N-k0

You will likely need to pull the instrument cluster and carefully inspect all the connections and circuit paths for damage or corrosion.

my best guess is the gauge moved to a position where the fuel gauge isn't making a good connection.

So if you do not want to mess around potentially causing more problems.

you may just take the front gauge cover off and carefully with a tooth pick or something move the needle to the empty position then turn the key on and see if it moves back to a position where you can see the fuel level.
If it does great. at this point you would need to verify its reading correctly.

To do this you would need to drop the tank remove the sending unit and manually operate the sending unit float having someone watch the gauge.

BTW I had to look up your past posts to find out you are working on a Beautiful 1968 Pontiac Tempest. at least I think that is what your working on. if not let me know what you have.

Good Luck I hope this helps some.
 
Wow I just left for vacation and forgot about this post somehow

Thank you for the detailed reply, the other gauges are working,
so according to what you´ve said the regulator is still good.

I think your best guess is right, but taking off the front gauge cover
is not possible as it´s a plastic plate that is clipped between dash
and gauge. Or is there a short cut that I don´t know ?
Reaching the screws behind the dash is a pain ... especially when you
have large hands xD

Yes it is the red 68 Tempest, love it and it´s pretty rare, most of them are
just rusty stains on some junkyard or ended up as gto clones. Honestly
I like it more than the gto, the crome bumper just makes the front look
perfect
 
Typically the dash is disassembled. If you intend to keep this car you many want to invest in the factory Chassis Service Manual and an assembly manual. You can try looking for them in the GTO catalog from www.amesperf.com
 
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