Recommendation On Where To Buy Sending Unit

I need to buy a sending unit for my 70 Cuda, (340ci engine).

The last one I bought I got from Classic Industries and it appears to be non-functional after I installed it. I verified the gauge is working properly and the tank has good ground. When measuring the resistance of the sending unit I get 18Mohm reading which says the unit is not working correctly.

Given that I don't want to have to replace the unit a third time, I am looking for a recommendation on where to buy one of these that is of better quality.

I understand with the exception of NOS all the aftermarket ones are not that good but I at least want to buy one that is functional and is reasonably accurate.

Also, is it possible to swap out the sending unit without having to drop the tank?

This should work from sponsor Dixe Resto
http://ebay.to/2ePrUvl

Got my sending unit, tank, straps, gas tank pad from Randy. Good to deal with

yes if the sender goes in the side of the tank (& most do) & it does on your 70 cuda. My 85 ramcharger I think I am fubared (& it is on empty)

I went thru 3 bad sending units. They are all junk. I bought one from Kramers auto and it reads perfect. He calibrates them and makes sure they are reading right before he ships them out.
http://www.kramerauto.com

I bought the 1/2" sending unit from Year One and it's great, no problems.

81 Megohms is leakage resistance. If your ground is good, the sender is open. You probably have lower leakage resistance holding a probe in each hand.
Craig

If it were my car, I would either find a NOS unit or have the original rebuilt. My aftermarket A body sending unit could not be calibrated to my gauges. I found a NOS unit at Carlisle and it needed almost no adjustment.

Finally found one that works but it came with the entire tanks. Spectra CR8CFI fuel injection tank with sender and pump. Full is 8 ohms and full deflection of gauge. Empty is empty. First aftermarket one that had done that for this car.
Craig

If yours is a 5/16, Dixies states that they have NOS ones in stock. You can change out sending unit w/o removing tank. Just remove heat shield in the way and make sure tank level is lower than the opening. You did not mention if you have a Ground strap for the sending unit to metal fuel line. It looks like this:

https://www.amazon.com/Mopar-Fuel-Sending-Ground-Strap/dp/B00MG12F0Y

http://www.dixierestorationparts.com/products.cfm?kys=fuel+sending+unit

Thanks. I ordered the NOS one from Dixie on eBay on Saturday. Just waiting to hear from them that it actually shipped.

So just checked the mailbox and the sending unit was in there.

I went out and measured the resistance with the float low (equivalent to empty tank) and it measured around 78ohms.

When I raised the float to simulate a full tank the resistance went down to about 16 ohms at about 4/5 full and then creep back up to 78 ohms at full. I did this a bunch of times and it was fairly consistent. Then I tried it by raising the float very slowly and I could get it to read 13 ohms at full. I tried doing this repeatedly (raising it slowly) but could not always get a 13 ohms reading every time (sometimes ~20 ohms, sometimes ~30 ohms and every now and again 78 ohms).

Does this sound right or do you guys think this OEM sending unit has an issue?

that sounds about right. a few ohms + or - doesn't make a difference.

that does sound like a big spread to me, maybe (hopefully) the contact pressure of the tang on the windings is varying as you manually move it out in the open & maybe it'll be different when installed with it immobile.You might with some jumpers wire it up to the blue sender wire at the tank & ground it & work it & have a helper holler what the gauge is showing. unfortunately that might be close to what you are doing now by just ohming it but I'd wanna do as much as I could before installing it & potentially having to go thru the mess of a R&R. keep us posted