More fuel sending unit

So i dropped the tank and removed the useless aftermarket sending unit. I will tell you i destroyed it in trying to get the gauge to work. I then took it apart and now i know why there not reliable, there made like the cheap imported **** that they are. Its garbage inside. I only hope a OE is made better.
I ran jumper wires from the sending unit to inside my car and worked the sending unit while i watched the fuel gauge. To things i found were the gauge is slow to react and it takes a lot of movement on the sending unit arm to get a reading on the gauge.
If we look at the total moment of the arm, say from empty to full, id think 50% would be half a tank on the gauge.
I put about five gallons in the tank which i had up on some blocks of wood. To get the tank to read quarter full i had to bend the arm in such a way that now the swing of the arm was less. What i mean is with the float resting against the tube as in a empty position the arm was not at the bottom of its throw its now about 30%. The gauge reads were i think it should with 5 gallons but i doubt its working correctly. I would have to see when i start to fill the tank up at what point does the gauge read full
I ordered another aftermarket sending unit which I'm hoping will work better
This really has me stumped. When i ground out the sending unit wire the gauge pegs all the way. But is the problem in the gauge? All the wiring is new and the grounds are good
Any thoughts are appreciated

With 5 gallons the gauge should read pretty close to empty. That why mopars go for ever on empty.

Try not to ground out that fuel gauge wire to long or you will also be replacing the voltage limiter.

But really the only reall way to fine tune the mopar system is with a reostat and ohm meter.
Check the resistane of the gauge and set the sender to like resistance.

steve from staten island said:

So i dropped the tank and removed the useless aftermarket sending unit. I will tell you i destroyed it in trying to get the gauge to work. I then took it apart and now i know why there not reliable, there made like the cheap imported **** that they are. Its garbage inside. I only hope a OE is made better.
I ran jumper wires from the sending unit to inside my car and worked the sending unit while i watched the fuel gauge. To things i found were the gauge is slow to react and it takes a lot of movement on the sending unit arm to get a reading on the gauge.
If we look at the total moment of the arm, say from empty to full, id think 50% would be half a tank on the gauge.
I put about five gallons in the tank which i had up on some blocks of wood. To get the tank to read quarter full i had to bend the arm in such a way that now the swing of the arm was less. What i mean is with the float resting against the tube as in a empty position the arm was not at the bottom of its throw its now about 30%. The gauge reads were i think it should with 5 gallons but i doubt its working correctly. I would have to see when i start to fill the tank up at what point does the gauge read full
I ordered another aftermarket sending unit which I'm hoping will work better
This really has me stumped. When i ground out the sending unit wire the gauge pegs all the way. But is the problem in the gauge? All the wiring is new and the grounds are good
Any thoughts are appreciated

Click to expand...

The very first thing you should do before installing any float type sender is to verify the ohm's reading from the bottom position to the top to ensure it operates in the range that the fuel gauge requires (75-10). I can tell you that due to the length of the swing arm and the depth of the tank, they do not read in a linear value. The length of the swing arm has to be adjusted and there are only a few companies that make such a sender. The problem you see is that if you have to bend the arm to keep the float from rapping on the bottom of the tank, the arm won't lift high enough to indicate "full" or at worse the float hits the top of the tank. Knowing the angle that the flange of the sender sits at when installed and the depth and angle of the tank, you really need to make a cardboard template that replicates this setup and check to see if the float travels the correct distance up and down without striking the lines on the template that represent the top and bottom of the tank and that the sender gives the correct ohms for full and empty. You can run a couple pieces of wire to the sender and connect the feed and ground temporarily. Move the float arm as the sender sits on it's side aligned with your template. You will know instantly if the arm has to be lengthened or shortened to stay within these constraints while rendering the proper ohms. I have replaced mine with a "tube" type sender that comes in many different lengths and ohms. You can find them at Summit and other places of business. This type sender in the proper length allows for a "reserve" when the gauge shows Empty. These type senders are "linear" and exact but require a slight modification to the tank because the mount vertically but it's no big deal.

No good. The tank is empty and the gauge reads 1/4 full. Im about to give up and while i very much apprentice your reply i dont really understand. I will look at Summit and thanks

I will save you some time. .ive been thru this with many of my chargers. .all aftermarket gauges are crap and will not work. .id try to find a original one that could be restored. .or you could buy that meter match control box. That's the only way to fix the aftermarket gauges. .junk junk junk

steve from staten island said:

No good. The tank is empty and the gauge reads 1/4 full. Im about to give up and while i very much apprentice your reply i dont really understand. I will look at Summit and thanks

Click to expand...

Your sending unit should be 10 ohms when the float lever is completely in the down position and 73 ohms when the lever is raised. If not then the unit you have is junk and does not have the correct spread of ohms to trigger the gauge accurately.
These ones work best and come in many lengths:

http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=346/mode=prod/prd346.htm

Pick what you need from here with the right 73-10 ohms that meets your needs:

https://www.google.ca/search?q=clas...cAhXo3YMKHX_mBm8QsAR6BAgAEAE&biw=1344&bih=698

Read this to troubleshoot:
http://www.tanksinc.com/index.cfm/page/ptype=results/category_id=159/mode=cat/cat159.htm

Yatzee said:

Your sending unit should be 10 ohms when the float lever is completely in the down position and 73 ohms when the lever is raised. If not then the unit you have is junk and does not have the correct spread of ohms to trigger the gauge accurately.
These ones work best and come in many lengths:

http://www.tanksinc.com/index.cfm/page/ptype=product/product_id=346/mode=prod/prd346.htm

Pick what you need from here with the right 73-10 ohms that meets your needs:

https://www.google.ca/search?q=clas...cAhXo3YMKHX_mBm8QsAR6BAgAEAE&biw=1344&bih=698

Read this to troubleshoot:
http://www.tanksinc.com/index.cfm/page/ptype=results/category_id=159/mode=cat/cat159.htm

Click to expand...

I have two 66 Mopars, one is an "A" body and another a "B". I've been chasing a fuel gauge issue with both. Both seem to react alike, as when the tank is filled the gage reads correctly...for 10 miles, then drops rapidly making me uncomfortable leaving the sight of a gas station. I've replaced the sending unit on both...twice. It's difficult for a "hobbyist", like myself to get into the inner working details of a $80 sending unit, I'd rather just swap it out.

I'm assuming that you are happy with the performance of the sending unit you're presenting. Is it a similar issue to mine that you were correcting for? Is it an easy conversion to this style?

I had a original unit "rebuilt/restored/reconditioned what ever i can call it. It still did not work properly. I just pulled it out of the tank and tested it. It reads from around 10 to 70 ohms. However anything in between is way off and erratic. I suspect thats the problem. I am waiting for what i hope is a better aftermarket unit and i will see how that reads. Other than that will try to find a NOS unit. Thanks to all