fuel sending unit 1948 plymouth coupe

[46Ply]

Okay guys, here's what I've learned regarding P15 fuel tank sending units.

 

Mike, (supernice guy) at -->          http://www.mykmlifestyle.com/Antique_Automotive_Parts.html

is very knowledgeable on this series of postwar Plymouth.  He told me that somewhere during the production period the dash gauge on these cars was optional, due to an $8 difference in the cost of the gauge. Either a 1 wire electromagnetic gauge, or a 2 wire thermostatic gauge was used.

Therefore, a 1 wire sending unit can be used on a 2 wire gauge, as well as a 1 wire gauge, but a 1 wire sending unit won't operate entirely correctly on a 2 wire gauge.  The gauge will read full on a full tank, drop off to about half, and then remain there until the tank is almost empty, then drop to empty.  ie:  The two wire gauges requires two hot wires to the sending unit in order to operate correctly.

 

 

 

Hope this helps for anyone going down this road.

[Plymouthy Adams]

_{per the book the last of the P15 was treated to the one wire.  the two are as different as night and day and nothing interchanges except their respective mounting positions..anyone having fuel gauge troubles needs to delve into the book...it truly explains the operation of each and clearly marks the differences..the sender units are also of two different ohm rating and the very means the signals are taken to ground}

[Young Ed]

_{per the book the last of the P15 was treated to the one wire.  the two are as different as night and day and nothing interchanges except their respective mounting positions..anyone having fuel gauge troubles needs to delve into the book...it truly explains the operation of each and clearly marks the differences..the sender units are also of two different ohm rating and the very means the signals are taken to ground}

How much the last of the p15? Mine is Nov 1948 production and has a 2wire. The 39-47 trucks have a 2 wire system too and supposedly the gas tank reproducer has come up with a 1 wire sender that will work with the 2 wire gauge by just using 1 of the terminals.

[Seaside Pete]

Thanks Pete,  That led me to the one I bought!  (ORG).  And it has 1 terminal only.  Their site doesn't tell which one it is.  Might be good info for anyone else that goes down this road however.  The price is right at $35. but not if it doesn't do the job.

If you are following the route I gave on the Tanks inc site, the "ORG - Early Ford & Mopar - 73-10 Ohms" is a 2 terminal sender not a 1 terminal. I am looking at it now.

 

Pete

[46Ply]

If you are following the route I gave on the Tanks inc site, the "ORG - Early Ford & Mopar - 73-10 Ohms" is a 2 terminal sender not a 1 terminal. I am looking at it now.

 

Pete

That's strange!  I ordered the very same unit and it has 1 terminal.  (To clarify, that's one terminal on top)  I've also talked to the rep there and He advised how to hook up a 1 terminal unit to a  2 wire dash gauge!

 

    ORG - Early Ford & Mopar - 73-10 Ohms  This is the one we're talking about.

Wish I had the reference Don speaks of.  My service manual doesn't show this information.

[Jerry Roberts]

If you are going to try the one wire sender , hook it up out of the tank . That way you can move the float through it's range of motion while looking at your dash gauge . Be sure you ground the sender . 

[46Ply]

Thanks Jerry,

I gave up and ordered a 2 wire sending unit from Andy Bernbaum.  But the supplier is kmlifestyles.com.

[TodFitch]

Thanks Jerry,

I gave up and ordered a 2 wire sending unit from Andy Bernbaum.  But the supplier is kmlifestyles.com.

Just curious, did the people at Bernbaum tell you that? If not, how did you learn this?

 

I've been wondering where the folks who claim to have a sending unit for the very early 1930s Plymouths get theirs and I've suspected they might be getting them from kmlifestyles.com But it has just been speculation on my part with no facts to back it up.

[46Ply]

Todd,  If you call mykmlifestyle.com,  I'm sure you could get your answer.  I talked to Mike,  super nice, knowledgeable fellow.

(I also replaced my dash gauge with a NOS '42 model gauge.  Just had to change the face plate.)  

 

And I do know that Bernbaum also sells asian made units!  I made sure mine came from mykmlifestyle.

Edited May 24, 2015 by 46Ply

[jgreg53]

My fuel gauge for my 48 Plymouth just stopped working again.  I have put 2 or 3 sending units in it and it's a new tank.  Are the sending units damaged buy the corn gas?  I'll change it again and it will work for a while. They usually last a year.  

[logo48]

This is my first post to this forum, I like to introduce myself: I'm living in Finland, Helsinki area. My Mopar is Chrysler Windsor 1947 which I have owned several years (since 1972).

The car is very much in original. Naturally some repars are done during these years.

I have been following this site some time and I have got lot of good information for maintenance the car.

I'm sorry about my not very good English. Hopefully there will be not very bad language mistakes.

 

About gas tank sender:

Couple of months ago, I bought new sender from eBay. Before installation I made resistance measurements of the sender. Unfortunately I found out that the sender was not functional. I sent e-mail to supplier but I never got any answer. Eventually I decided to open the device and I saw the problem, the circuit board was broken and the resistor was not in contact to the other contact point. Probably assembly error.

 

I fixed the broken board and bad connection using small screw. Result was positive, the sender works in the car. Still there is one problem: the reading is not linear because of the shape of the resistor. In original sender the resistor shape is designed to compensate the nonlinear arm movement. Also the aftermarket sender is not very roubust and I cannot expect very long lifetime.

 

I think that I will fix the original device again (I have rebuild the resistor wire about 25 years ago).

[Chachos 49]

On 5/23/2015 at 4:13 PM, Jerry Roberts said:

If you are going to try the one wire sender , hook it up out of the tank . That way you can move the float through it's range of motion while looking at your dash gauge . Be sure you ground the sender . 

How do you ground the sender a 1 wire sender?

[Sam Buchanan]

Clip one of the test leads to the mounting plate of the sender, the other goes to the terminal. The sender grounds through the tank when it is attached to the tank.

Edited May 5, 2020 by Sam Buchanan