Fuel gauge and sending unit help.

paulrhd29nz

Does anyone know what the ohms reading should be for the fuel gauge and/or the sending unit on my 46 truck. It has stopped working and the manual is of no help and I would like to be able to find out which part has failed.

Is there a replacement for the sending unit that anyone knows of?
It's still 6v.

Thanks.

Glowplug

Check the voltage regulator for proper out put volts.

paulrhd29nz

I have both the gauge and the sending unit on the bench wired up to a new 6 volt battery. Nothing works. How do I tell if the gauge is toast or if the sending unit is not functioning?

Paul.

Glowplug

http://hudsonrestoration1948-54.com/Dash Insturments.htm

Go here

Per

Paul,

Connect the gauge to the battery briefly.  The gauge should move all the way.  If it does, the sending unit isn't working.  My guess is that the sending unit is the problem.

I replaced the tank sender unit with one that fits Ford pickup trucks.  A website that has pictures of the unit is www.cgfordparts.com.  It fits 6 volt Ford trucks F-1, F-2 and F-3, 1948-1952 according to them.  Price is $39.50. Their part number is 7C-9275-6V.  I bought mine from a local independent parts store three years ago for about this price.  They said it fits 6 volt Ford pickup trucks, so I think this is the same one.  The round plate with six holes is identical to the defective one I removed from a l949 Hudson.  It is necessary to bend the arm between the unit and the float to make sure the float is almost touching the bottom of the tank when the tank is empty.  Otherwise there will be error, such as the tank being almost half full with the gauge saying empty, and the gauge only saying about half when the tank is full. 

I'm not sure if the mounting plate is the same for a '46 and a step-down.  You might see if you can find one at a local parts store by mentioning these trucks.  Bring you sample to be sure the mounting plate is identical.

As I remember, the resistance at the empty position is about 100 ohms.  At the full position it is close to 0.

Per

paulrhd29nz

Oldfarmer and Per , thank you very much for your reply.
Old farmer , my 46 has no in dash voltage stabilizer/ regulator. In your instructions on how to check it says " early cars with out .... Theses instructions do not apply ".
Does that mean if I get the sender that Per says fits a 48 tank, it may not work in my 46 ?
Or.. do I get a gauge and sending unit that works with the regulator and install all three?
Assuming Per's Ford sending unit bolts up to my tank. ?

Per

Paul,

     I do not have a voltage stabilizer. My gauge gives a correct reading (anyhow, what I feel iscorrect) when I am driving so the engine is going fast enough to reach the voltage determined by the car's voltage regulator.  

     If the car is idling slowly (the generator not charging), or is not running but the ignition is on, the reading on the gauge is about 1/8 gauge lower.  For example if the gauge reading is 1/2 when driving, it is 3/8 when standing.  The gauge does not change quickly, because it is "damped", so if you rev up the engine, it will move very slowly from the lower reading to the higher reading.

                   Per

Glowplug

Per great explanation... Generator equipped cars change voltage output with engine speed... Precisely why the voltage stabilizer was adopted to put out a constant voltage.

Per

Paul,

     I just found the receipt for the fuel gas sending unit I bought several years ago.  It turns out I bought it from a dealer on ebay (after having done the research at a parts store).  The same dealer is still selling this part.  Put in ebay number 140491165127.  The price is $33.96 with free shipping.  This is about $9.50 less than when I bought mine in 2011!

     You will see a very clear picture of it there.

              Per

bob ward

I need a sender for the fuel tank I'm making for my 35 H8 project. The sender mentioned above is probably physically suitable but I have no idea if its 100?ohm resistance range is compatible with a 35 fuel gauge. 

Does anyone have this info?

Per, can you send me your email please?  bobwardDOTlaidleyATgmailDOTcom

Bob

Per

Bob,

     The easiest way to check this is to get some resistors.  If you get a package of the same resistors, for example 15 ohms or 22 ohms, you can see the behavior of the gauge as you put each additional resistor in series between the gauge and ground.  In my connection, I found that about 20 ohms caused the gauge to reach full, so I left a 20 ohm resistor in the circuit.  The gauge registered empty with 100 ohms.  It registered below empty when off.

                     Per

Per

Bob,

My email is perauto at gmail.com