fuel sending units , c'mon

[poppa]

Can't I get one that even remotely close?   Wuz up wit dat?? On empty until 3/8 ,and only goes to 7/8 when it should say full. Got 2 from different places ,one has plastic float , one has brass so I'm pretty sure 2 different manufacturers. HELP !!!!!!!    

[Ghoste]

They're all pretty much junk as far as I've been able to find out.  A lot of them claim to calibrate them but they seem to all use the same style of rheostat.

[poppa]

I believe it ohm's out correctly ,10 and 73???

[Pete in NH]

Hi,

At 73 ohms the gauge should read empty and at 10 ohms full. At 24 ohms the gauge should read 1/2 scale. That is where the problem is with  the repop senders. Mid way between 10 and 73 is 41 ohms not the 24 the Chrysler specification calls for. The repop senders are apparently wound in a linear manner not the tapered nonlinear manner of the originals.

This has been an ongoing issue and it's beyond me why the original resistance winding can not be copied. I suspect all the reproduction junk is coming out of China and vendors selling this stuff don't seem to care that what they are selling is incorrect and insist on getting the part made correctly. There was some talk about getting senders made by the original manufacturer but, I don't know what ever came of that.

There is an electronic conversion device that claims to match these poor reproduction senders to the Chrysler system. I don't know anything about them but take a look at http://technoversions.com/MeterMatchHome.html

[poppa]

That (original manufacturer ) fell through. I called early this spring. Probably not enough to make a run. Bummer

[Lennard]

Bring the poor quality under Classic Industries attention? If anyone can persuade a manufacturer to change their ways it's going to be a giant business like them.

[Dodge Don]

http://www.1970chargerregistry.com/mboard/index.php?topic=3537.0

[Lennard]

http://www.1970chargerregistry.com/mboard/index.php?topic=3537.0

Great, thanks for the info!

[maxwellwedge]

I'm still skeptical......a little less......but still. 

I guess I'll try one.

[Ghoste]

Me too, on both points I guess.

[poppa]

I ended up getting 2 ,one from Rock Auto and one from Kramers.I hooked them both up ,outside the tank , Kramers went to 7/8ths so I used that one. Now in the tank it goes to 3/8ths. Go figure. I will pull again and the gauge cluster and try to calibrate one more time.

[el dub]

 how many gallons is a tank supposed to hold?

[myk]

19?

[John_Kunkel]

Whenever I doubt a senders accuracy I use half-watt resistors (75, 25, 10 ohms) between the tank connector and a good ground...this will tell you if the body side of the gauge circuit is accurate.

[poppa]

John , between the connector and a good ground , on the ground side??? Thanks for the help

[John_Kunkel]

Use jumpers to hook one side of the resistor to the wire that goes to the fuel sender and the other side of the resistor to ground. The system uses the metal fuel line as ground but I don't trust that, use a bare steel part of the frame (then check for continuity between the frame and the fuel line).

10 ohms should be full scale on the gauge, 25 ohms about half-tank and 75 ohms empty.

[John L]

I ended up getting 2 ,one from Rock Auto and one from Kramers.I hooked them both up ,outside the tank , Kramers went to 7/8ths so I used that one. Now in the tank it goes to 3/8ths. Go figure. I will pull again and the gauge cluster and try to calibrate one more time.

I also got a sending unit from Kramers after reading how good they were on the 70 registry. I checked it before installation and it worked great and the gage went to full. After buttoning everything up and filling the tank the gage only went to just above half (very frustrating). I have a suspicion that the float does not go all the way to the upper stop tab, but I will not be able to test that out until I run the tank dry again so we will see. I'm going to hit Radio Shack next week and try John's testing method using the resistors.

[charger Downunder]

Went through the 3/4 tank some time back with a new sender. Had to bend the float shaft a pain to do. I had to bend it in a way so it would let the sender unit that is covered up get to the end of its travel plus i bent the stop pin a bit too. Hard to explain you dont bend the end of the shaft where the float is. It has to be bent where it comes out of the sender unit itself. Make sure you bend it the right way. You want to get more upwards travel on the shaft before it hits the stop. So it has to be bent down.

[Ghoste]

Who did you buy it from and does it read correctly in the other parts of its travel now?

[70sixpkrt]

Any updates on this? I need a new sender also.

[Kern Dog]

It almost makes sense to modify an OEM 5/16" sender with 3/8" tubing.  Factory accuracy with improved flow.

[Dino]

It almost makes sense to modify an OEM 5/16" sender with 3/8" tubing.  Factory accuracy with improved flow.

Don't make it too hard.  Buy a new 3/8" sender, remove the resistor box and weld the one from the 5/8" sender in its place.  Cut both ground straps, overlap them and weld them together.  Problem solved.  Been running mine like that since last year and the fuel gauge is spot on.  It's on my bench waiting for the new tank so I can get some pics tomorrow if you want.

[Ghoste]

Provided you have an old one.

[Lennard]

I think it's ridicules that after you've spend over $100 for the #@*°  thing, you have to take it apart/modify/rebuild it to make it function properly!

[66FBCharger]

Don't the new sending units available from Kramer's solve the problem?