0 - 90 ohm fuel gauge with a 0 - 30 ohm sender [Archive] - Chevy Nova Forum

: 0 - 90 ohm fuel gauge with a 0 - 30 ohm sender


flamed64ss
26th-November-2008, 11:26 PM
Alright guys I need some help. I changed the gauges in my 64 and the fuel gauge is a 0 - 90 ohm gauge which reads wrong. I now know the sender ohms and the gauge ohms are different therefore the gauge is not going to work right. The tank is all but full and I read 37 ohms at the sender pin on the tank to ground today. The gauge is pegged past full. I know a bad ground connection can cause problems also but I have checked the grounds and they seem to be good. I read online where a potentiometer of approximately 0 - 100 ohms can be added in series with the sender wire then adjusted precisely to make the gauge/sender combo work. If I am not mistaken the resistance of the sender should be 0 at empty and 30 at full for these units right? If you add a resistor of any value in series with another resistor then you are increasing resistance. So if you add a resistor in series with the sender wire then the value of the sender should be added to the value of the resistor you added, right making resistance increase. By doing that, even when the tank is empty the sender would read 0 ohms the resistor you add would make the gauge think it still had some level of fuel in the tank ,right thus causing the gauge to read wrong. Is that correct or does that put the potentiometer in parallel with the sender causing the resistance to be adjustable to get the 0 - 90 reading to make the gage read right? I am trying to make this an easy fix and use the 0 - 90 gauge so any help is greatly appreciated.

Thanks, and Happy Holiday
Scott

Rich
1st-December-2008, 07:27 PM
The "easiest fix" would be to replace your sender unit with one from a 65 to 67 chevy II. They are 0-90 ohm. :yes:

Rich

flamed64ss
4th-December-2008, 09:50 PM
The "easiest fix" would be to replace your sender unit with one from a 65 to 67 chevy II. They are 0-90 ohm. :yes:

Rich

Rich, are the 65 - 67 senders the same dimensions as the one in my car now -you know like the depth inside the tank, and the flange diameter etc.?

Scott

Rich
4th-December-2008, 11:34 PM
Is that a trick question?

I don't know what's in your car now.

If it's a stock 64 tank, the answer is yes, that's what makes it easy. :rolleyes:

Rich

crazy88
6th-March-2009, 03:45 AM
ok i dont wanna cluter the forums with new threads, can some one tell me
what the fuel level ohm are for a 69 nova.
it originally had a inline 6, and the sender is still original.

im getting an autometer gauge and don't want to get the wrong one.

wskaiser
6th-March-2009, 09:45 AM
should be 0-90

crazy88
7th-March-2009, 05:55 PM
thanks a bunch!:)