70 Charger Fuel Sending Unit Help

[A6USMC]

Can anyone suggest a quality supplier for a fuel sending unit for a 70 Charger?
It seems a lot of people have had problems with replacement units. Kind of hoping someone has found a good one. Thanks, Brian

[Nacho-RT74]

As far I know, there is no change on the market options

[b5blue]

Check with John, others have said they are good.    https://www.johnwolfco.com/

[Mike DC]

   
The longstanding problem is that the repro senders have the float sweep done in the GM electrical pattern.  It reads correctly in the middle of the sweep but it gets less accurate as the tank moves away from half-full.

It's one of these things where the repro parts maker keeps being alerted to the problem, and they keep saying "Okay we'll fix that" for the next 25 years.   

[b5blue]

The sweep inside the factory unit is hour glass shaped and repops have a even strip. That along with the odd shape and angle of the tank creates complex issues. I used a "Meter Minder" to somewhat correct my gauge.

[Kern Dog]

The longstanding problem is that the repro senders have the float sweep done in the GM electrical pattern.  It reads correctly in the middle of the sweep but it gets less accurate as the tank moves away from half-full.

It's one of these things where the repro parts maker keeps being alerted to the problem, and they keep saying "Okay we'll fix that" for the next 25 years.   

Rick Ehrenberg has written that the Mopar units read in an elliptical curve while the reproductions are made to read in a linear fashion. Like you wrote above Mike, the aftermarket doesn't give a shit to correct it.
I have a 3/8" sender I bought from Year One in 2001. It has always been wonky but consistent.

[timmycharger]

I gave up on trying to find a sending unit that wasn't crap. I ended up using the Meter Match from Tanks Inc.

It was a small amount of work to get it set up, I filled/emptied my tank a few times to calibrate it perfectly. Did this last year and have not looked back.


https://www.tanksinc.com/index.cfm/page/ptype=product/product_id=748/mode=prod/prd748.htm?srsltid=AfmBOoqL1L8u1wr_0ZnC6IPjEFfaF1mBhL7M9xN_EhYox6Isa-abYm2M

[Nacho-RT74]

The linear and logarithmic reading difference on senders reading is because originals rheostats are like this:



While repro/replacements are like this

[Nacho-RT74]

It seems however... this could be fixed

There are rheostat replacements available. Not in USA thought

https://www.hemiperformance.com.au/shop/shop-by-category/electrical/sender/fuel-sender/fuel-tank-sender-resistor-unit-suit-sv1.html

Thinking seriously on this. 

[Nacho-RT74]

The sweep inside the factory unit is hour glass shaped and repops have a even strip. That along with the odd shape and angle of the tank creates complex issues. I used a "Meter Minder" to somewhat correct my gauge.

I Read this after my last posts LOL

[b5blue]

 

[WINGMAN]

Unfortunately most aftermarket parts are not as good as Ma Mopar . Most parts you can make work with a bit of work. The fuel sender issue can fixed if you have the skill using a N.O.S. sender from a different model car like a c body as a doner. They are on E bay from time to time. Find one that the rheostat looks the same. Cut the ground strap at different lengths on the new one and the old one. Remove the sender from the pipe on both the old and new units. Then you will need to tac weld the new sender to the old unit.  You might need to modify the float arm. Then solder the two ground straps. Yes its a lot of work but if you do it right it will out last you.

[A6USMC]

Thanks all for the replies. I went with an early reply and bought one from Van's auto parts getting installed this week. I'll give a report on how it works afterwards.

[b5blue]

Best to empty tank and check for zero then add 5 gal. 3 times to mark movement.

[Kern Dog]

No, 4 3/4 gallons 4 times. The 68-70 Chargers have 19 gallon tanks. Check my math. 19 divided by 4 is.....

[Mike DC]

         
Chrysler said the 68-70 Charger tank was 19.5 gallons.  I don't trust gas station pumps enough to be entirely sure.


 
As for the sending units -

Could somebody just reproduce the correct wire grid portion for our cars?  Is it the same one in most/all vintage Mopars?  Then we could use the existing repro sending units (the ones that read wrong) and fix them. 

It would still involve some troubleshooting/testing.  But we all know that. 
 

[70 sublime]

Could the factory wire grid section from an old fuel sender be moved to the new unit ?
I have the old crusty one and the new unit to go in my new tank

[Mike DC]

Could the factory wire grid section from an old fuel sender be moved to the new unit ?
I have the old crusty one and the new unit to go in my new tank

If the old sender is still electrically functioning then why use a new sender?  You might as well just rehab the old one. 


The fuel line pickup size might be a reason to use a new sender. 

Stock 318/383 cars came with 5/16" fuel lines. 

440/426 RT cars came with 3/8". 

Repro senders can be bought in 1/2" too. 

[Kern Dog]

Chrysler said the 68-70 Charger tank was 19.5 gallons.   

The glovebox owners manual reads 19 gallons. Service manuals read 19 gallons.

[70 sublime]

Could the factory wire grid section from an old fuel sender be moved to the new unit ?
I have the old crusty one and the new unit to go in my new tank

If the old sender is still electrically functioning then why use a new sender?  You might as well just rehab the old one. 

The pipes are rotten where they go through the plate from inside to outside the tank


The fuel line pickup size might be a reason to use a new sender. 

Stock 318/383 cars came with 5/16" fuel lines. 

440/426 RT cars came with 3/8". 

Repro senders can be bought in 1/2" too. 

[Mike DC]

The glovebox owners manual reads 19 gallons. Service manuals read 19 gallons.

Huh. 

I know I've seen that 19.5 number in a few places.  I thought it was from Chrysler but maybe it came from magazine road tests.  They probably topped off the tank up the filler tube.  And maybe their gas pumps were overcharging them a bit.

Either way it's an oddball number.
 

[Nacho-RT74]

As for the sending units -

Could somebody just reproduce the correct wire grid portion for our cars?  Is it the same one in most/all vintage Mopars?  Then we could use the existing repro sending units (the ones that read wrong) and fix them. 
 

I posted the piece being made and sold from Australia.. reply #8