fuel sending units

[crickkid]

I just purchased a 49 plymouth and the sending unit does not work, after looking things over I found that someone had put in some aftermarket oddball unit that won't register correctly or at all. It reads full most of the time and will come off a little when it gets near empty. I have purchased an original style unit and was wondering if it will work since my car has been converted to 12 volts. I don't know how they did the conversion, but just know that it is 12 volt starting and lights...

[chopt50wgn]

If the starting system and lights are 12V, you can bet the rest is 12V as well.

You should test the sender for the correct OHMs that correspond with the gauge. I would make sure the new gauge is also 12V cause if it isn't and you connect it to the 12V........well you know what happens.

[BobT-47P15]

Can't you use a reducer (like Runtz) to reduce power at the gauge?

Heres a link to some old posts on the topic.........read thru them to see if any apply to your situation........................

http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=1045&highlight=reduce+power+gauge

Edited December 10, 2012 by BobT-47P15

[Robert Horne]

I am using a 12volt ford gauge, with my plymouth gauge face on it.

I have a Datson sending unit. I installed a 12volt to 6volt reducer,

(for gauges), and it all works great.

Running 12 volt gave me high readings on the fuel gauge....

[Robert Horne]

Here is the 12 to 6 reducer for gauges....

http://www.ebay.com/sch/i.html?_sacat=0&_from=R40&_nkw=12%20to%206%20volt%20reducer&_sop=15

[crickkid]

Thank you guys for all of the info. I will check and see if maybe my car already has the 12-6 volt reducer on the guage. That might be the reason that it reads full most of the time. Also the sending unit that is in there now has two terminals and 49 plymouth should only be a one terminal unit. I now know what to look for. The posts on figuring voltage and amps are confusing to me on first read, but after some studying will be able to figure it out.

Thanks again,

Bill

[Mikemomd]

Similar issue related to the original post.....

 

I installed a new tank along with a new sending unit. The ground lead terminal I grounded to the trunk floor....the other terminal I connected to the original line that was connected to the original sending unit. I have a 12 volt system....my fuel gauge is showing nearly full and not budging when I know it should be. I purchased the 12-6 volt reducer....can I connect the reducer in line at the sending unit under the cover just as the lead is leaving the sending unit????

 

Thanks,

Mike

[Andydodge]

My 1940 Dodge has been hotrodded & 12 volt since 1973, the stock fuel sender unit is still used in the stock fuel tank however the fuel guage has a 12volt resistor wired into its circuit and has read fine now for 40+ yrs........andyd