I thought I had a problem with my fuel tank, but now it appears that the fuel guage AND tempurature guage are both not working. Anyone have any thoughts on what might be the problem.

Oh yeah, this is a 76 cordoba

Thanks for any info

check fuses.

Depending on the car, could be a combination of problems, but the most likely is the instrument voltage limiter, on some earlier Rally dash cars, the limiter is built into the fuel gauge, but on most of 'em it's a separate plug-in module.

The originals were just like a signal blinker--they cycle on/off to reduce 12V to a puse equivalent of about 5V, that is, about a 50% duty cycle pulse.

Do yourself a favor and buy a solid state replacement RTE (Real Time Engineering) is one place

For some reason I cannot get their web page to display this morning

You can also Google around and find various projects on building one from a 5V voltage regulator

I'm guessing yours is the non-tach dash due to having the fuel and temp gauges
together?! Here are both circuit boards, the voltage limiter is the same for both.
There are two on eBay right now, one used for $50.00 and another solid state for
$30.00. I have a complete non-rallye gauge set I'll let you have for $50 if you need it.
Comes with PC board w/Voltage limiter, Fuel, Water temp, Ammeter and Oil gauges.
Also gauge lens pod.

With out Tachometer:


With Tachometer:

Guys there is multiple videos on the internet on how to solder in a 7805 voltage regulator. It's not hard at all.

Thanks for all of the input. I hope that one way or the other, I can get this fixed.

Just thinking this through, if I had a ground problem with the fuel sending unit, would that have an affect on the temperature gauge? Or another way to put it, if they both are not working it's either a bad gauge unit, the voltage regulator is bad or.....?

Any ideas are appreciated

UPDATE - I am halfway there! I replaced the temperature sending unit and my temp guage is working now, so it looks like I will be looking at the fuel sending unit (or possibly the float) to get the final part of the problem fixed.

Unless...anyone has any thoughts otherwise.

I have the same issue, my temp and fuel gauge don't work on my 74 non tach dash. I check my sending unit and that was good. I'm thinking its the voltage limiter or a grounding issue.

Finally, problem solved!

The float on my sending unit, had a pin hole in it and was full of fuel. I switched out the unit and the fuel gauge is working great now!

Thank you to all for your help and advise!

Did you check the temp sending unit? Also the float on the fuel sending unit? Mine had a pin hole in it (almost invisible to the naked eye) and had filled with fuel. The sending unit functioned properly when I attached the meter to it, but the float was full and didn't work.

If those are not the problems, I have an extra fuel/temp gauge(nos) and voltage limiter if you are interested.

Yeah I took my fuel sending unit out and I checked it for a voltage increase when the float went up and down (I forget the actual numbers but that was good). Then I looked at the float and that didn't have any fuel in it and appeared to be in good shape. I'm thinking it may be the voltage limiter because both temp and fuel gauge don't work. Actually the three smaller gauges on the right side of my cluster doesn't work.

So yeah I may be interested in your fuel/temp gauge and/or voltage limiter.

PM me if you want to do something.

i have a 70 fury 3 that the fuel gauge will only go up to about half a tank. i have tried replacing the sending unit and i have replaced the entire instrument cluster. any ideas?

Could be the voltage limiter on the printed circuit board for the instruments

My temp and fuel either both work or neither works, I am assuming a grounding issue? This would rule out the voltage limiter,right? 1969 roadrunner