When the fuel sender is at full I am getting 114 and empty it is 14. How far off will this make the gauge reading? I assume it will just read full longer and run out sooner?

 

What happens if you set the meter to 200ohms, use a clip lead and not have your hand on it?

 

I should have stated it should read 90. My hand was not on the lead.

 

Your hand may not be on the lead, but it is touching the tubing that the lead is connected to. I understand that it should be 0-90 ohms, I doubt that the little variance will matter much in terms of gauge swing. You can hook it up to the car and verify how the gauge reacts also. Remember that an open ground circuit drives the needle way past full, and a shorted one drives it past empty.

 

What kind of battery is in that meter?

Most need a non-alkaline for accuracy. Don't ask me why. It'll be in the directions, and nearly everyone swaps in an alkaline battery as they are everywhere..

 

If it were me, I'd stick the sending unit back in the car and live and get used to with whatever readings it gives you. While those units were nominally 0 ohms at one end and 90 at the other, who knows to what degree of precision that was actually true. Gas gauges back in those days were never precision instruments, and 114 might have been considered within the tolerance range of the 90 ohm specification. Ditto for the 14 at the other end.

If you really want to see how good you can get, can you just buy a new sending unit? That's likely what I'd do if I had gone through the trouble of dropping the gas tank and getting the old one out. Assuming new ones are available.

 

I believe there is a dimension in the CSM that the float is set to. This can also affect gas guage accuracy.

 

Eric, try some CRC contact cleaner. Last year i was installing a new fuel sender in my 67 442. I was getting inconsistent readings. After using the contact cleaner, the readings were better. you may have some oxidation on the rheostat.

 

Hmm. Good point, it may be able bring the readings down by 14 degrees on both ends.

 

Setting the float level doesn't change the Ohms on either end. If set to low, it will reach the full level on the gauge before the tank is physically full. If its set to high, the car will be out of gas before the gas gauge hits empty. Both Ohms and float setting are important to gas gauge accuracy.