Fuel sending unit help

[steve57dodgetruck]

I have searched the previous posts, but still seek additional help. I have '57 d100, original 12 volt everything. My gas sending unit failed and all I was able to find was a 6 volt replacement. The gauge reads between full and 1/2 (reads 1/2 when empty). *I have tried putting online resistors in between the tank and the sending unit, without success. With various resistors the range lowers (1/4 - 3/4) but can't get the entire range of the gauge. Suggestions?

[W.F. Brown- III]

I have a similar problem with my '48 Plymouth's gas gage. Mine (a 6 volt system) reads 1/2 when the tank is full. I've tried everything I can think of to correct, but still only registers a half. So far my solution has been to fill it up when it shows empty (which is really a half-tank). I'd be interested in possible solutions to your problem, as they may also apply to mine.

[randroid]

steve57dodgetruck,

Have you checked the range of motion of the arm on your 6v sending unit? The logical answer to why it doesn't work correctly is you should get a 12v unit but I've never tried to interchange them and your use of resisters is producing some sort of results, so does the arm swing all the way from the bottom of the tank to all the way to the top? Have you tried it out of the tank to make sure is isn't getting caught on the side, etc? I find it almost amusing that you can find a 6v unit and not 12v but unless you can ascertain the problem lies in the range of motion I'm afraid you might need to actually get the correct sending unit.

W.F. Brown, III,

The problem you're having has no relationship to the other query. Your sending unit requires two wires, one for each half of the range (as I recall; it's been a while since I've looked at mine). The trouble you're having is the symptom of one of your wires not being connected. There are diagrams and discussions on that topic in the search engine and they will tell you precisely what to do about it, which might be why I'm the 75th person to read your post and the first person to answer it. Click the Search button and enter something like "two wire P-15 gas sending unit", or something like that. It may require that you change the wording of your query a bit but there are numerous posts on your problem.

Good luck to both of you and please post the outcomes.

-Randy

[W.F. Brown- III]

... W.F. Brown, III,

The problem you're having has no relationship to the other query. Your sending unit requires two wires, one for each half of the range (as I recall; it's been a while since I've looked at mine). The trouble you're having is the symptom of one of your wires not being connected. There are diagrams and discussions on that topic in the search engine and they will tell you precisely what to do about it, which might be why I'm the 75th person to read your post and the first person to answer it. Click the Search button and enter something like "two wire P-15 gas sending unit", or something like that. It may require that you change the wording of your query a bit but there are numerous posts on your problem ...

Thank you.

[steve57dodgetruck]

Yes I have been doing all my trouble shooting with the sending unit out of the tank, so it isn't getting hung up. It is somewhat amusing I can only find a 6 volt unit, but I guess that is life. Collectors Auto Supply has a 12 volt unit....for $225! This 6V gauge I have is from Roberts, because "something was better than nothing." My original 12 volt gauge failed and I am kicking myself because i disposed of it before realizing that such things could have been rebuilt!!! I think I saved every other part i replaced during my restoration, but for some inexplainable reason I ditched the sending unit

If anybody has any other ideas, I'd appreciate it. Thanks.

-Stephen

[Rodney Bullock]

JC whitney I just bought a sending unit and gauge for my 53 truck (Sunpro) 12 volt

[yourpc48]

From what others told me when I posted about my fuel guage if the sending unit and guage are matched 12 and 6 shouldnt make a difference. I dont know that as fact but I do know that there are at least 2 distinct types of wiring setups for the Guage systems. I have a 47 P15 so if you have one like the P15 you will have a 1 and 2 on both the guage and the sender. Make sure the 1 on the guage goes to the 1 on the sender. Likewise with 2 to 2. Then there is a hot on the guage and make sure to have a good ground on the sender. I have added some images of mine while I had them out. Maybe this will help.

[steve57dodgetruck]

Before Buying another sending unit that I'd have to modify to fit my tank I decided to send mine to a company that thinks they can alter the internals to make it work. If it works I'll post name and contact information.

[1941Rick]

I converted my 41 p12 to 12 volt a year ago...still have the 6volt gauge....when you turn on the key the gauge would jump to indicate the level...I put a small dash light bulb in the circuit and that slowed down the needle...gauge is still accurate....