12v fuel sending unit..??

[claybill]

when switching your car to 12v..what do you do about the fuel tank sending unit when usingto a newer set of dash gauges?? or will it still work?

bill

[Norm's Coupe]

Bill,

It all depends what type gauge the new one is. If it's not the thermal type like the original was, then you would need a one wire sender. You can determine that by looking at the gauge. If it's a single wire post on the gauge, then you need to change the sender to a single wire type.

[1949P17BC]

Good question, I changed over to 12 v but have a 6 volt dash gauge and 6 volt tank unit?

[Plymouthy Adams]

theoretically the three wire system has a built in 5 volt regulator into the dash guage itself thus providing regulated voltage to the circuit...when used with 12 volt system most folks find that the cycle rate is a bit faster..and you may see a slight twitch if you will in the needle..either way 6 or 12 it takes a few cycles to "properly" move the hand to reflect fuel level..the more full it is the more cycles to adjust as it only drives with a volt on condition..thus when the regulator is open, the dampening of guage is slow and remains somewhat steady till the next cycle...it takes good path through the resistor on each wire respectivbely to properly drive the guage as the sender splits the 30 ohms equally though disportionate per lever height..in other words if 12 ohms is on one lead the remaining 18 is on the other and both are taken to ground.

[claybill]

hi tim...thanks for the info and reply....but i have absolutely no idea what you are talking about. just electrically ignorant I am..

bill

[Norm's Coupe]

Bill,

Look at the back of the newer gauge. If it requires a single wire sender you will only have two posts for wires to connect to it. If the gauge requires a two wire sender, it should have 3 posts on the back for connections. Each post is labeled/stamped as to where the wires go.

[Young Ed]

Bob T has I believe an amp gauge from a 51-52 plymouth mounted in the smushed p15. Havent seen the back of it but it looks like it bolted right in. Perhaps if you took the time to switch the gauge face and paint the needle you could have a match and convert to a 1 wire. Myself though I prefer the 2 wire setup. Sure the sending unit is expensive but the 1 wires are direct read and bounce all over the place with each slosh of the gas in the tank.

[steveplym]

I've got the two wire setup and with the Runtz voltage reducer for the fuel gauge it reduces the voltage down and it works fine. Works just like it did on 6 volts actually, guess cause it still is. It was easy to hook up and is pretty inexpensive.