69 Cuda which sending unit do I need?

[twalt87]

Firstly I will apologize if this doesn't make sense, I'm at work and sneaking this post so its rushed.
So got this car from someone who was turning it into a drag car, the fuel tank has been modified on the bottom with a square tank welded to the original tank with large braided fuel lines coming off running to an electric fuel pump.

The tank never had a sending unit in it as he didn't get that far, So i ordered a Spectra FG69A and threw it in, the gauge has never worked correctly, it will read full, then move to half, then empty, in about an hr of driving, using a rope camera the tank is more then half full.

So my question, When I look at the various spectra units made for this year, they are all shaped differently. So im wondering if the level is wrong due to the wrong sending unit being used. Were there multiple tanks? and how can I tell which tank I have?
When I test the gauge it seems to work as it should using a 9v battery.

Ps- I hate the previous builder for throwing away the original lock ring *cries*

 

[Murray]

The problem you are having is more related to the variable rheostat on the sender. This is a problem area for all reproductions. As for shape- there is only one correct shape. You should check other sites as to what is correct.

 

[Icetech]

@halifaxhops has original rings for sale.... and do you have a ground to the sending unit?

 

[twalt87]

The problem you are having is more related to the variable rheostat on the sender. This is a problem area for all reproductions. As for shape- there is only one correct shape. You should check other sites as to what is correct.

@halifaxhops has original rings for sale.... and do you have a ground to the sending unit?

Will look around some more and find the correct design, the outlet is irrelevant as its capped off.
I'm not 100% sure if there's a ground going to it tbh, I think so but can't remember, will look tonight.

 

[Icetech]

Will look around some more and find the correct design, the outlet is irrelevant as its capped off.
I'm not 100% sure if there's a ground going to it tbh, I think so but can't remember, will look tonight.

the ground is super important.. but normally they won't work at all without the ground... just something to look at

 

[RedFish]

Firstly I will apologize if this doesn't make sense, I'm at work and sneaking this post so its rushed.
So got this car from someone who was turning it into a drag car, the fuel tank has been modified on the bottom with a square tank welded to the original tank with large braided fuel lines coming off running to an electric fuel pump.

The tank never had a sending unit in it as he didn't get that far, So i ordered a Spectra FG69A and threw it in, the gauge has never worked correctly, it will read full, then move to half, then empty, in about an hr of driving, using a rope camera the tank is more then half full.

So my question, When I look at the various spectra units made for this year, they are all shaped differently. So im wondering if the level is wrong due to the wrong sending unit being used. Were there multiple tanks? and how can I tell which tank I have?
When I test the gauge it seems to work as it should using a 9v battery.

Ps- I hate the previous builder for throwing away the original lock ring *cries*

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9 volts through an OEM gauge is nearly twice too much and will very likely kill the gauge. Closest to OEM senders shape is sold for A-100 van. It still wont be right at the dash but at least closer. In the end you'll need a addon product such as meter match to calibrate sender resistance to gauge needle position.

 

[mvh]

The problem is that ALL the reproduction senders have a different shape than the factory one (there was only one OEM tank and one sender for 67-69 Barracudas). The pivot point is much lower and the arm is much shorter, and the entire tube is a different profile. On top of that, the rheostat windings are evenly spaced, not proportionally spaced to account for the shape of the tank (which has a smaller volume in the upper half than the lower half because of the spare tire well). The only real solution is to find an OEM sender in good condition, or refurbish one. Top item in photos is OEM unit, bottom is "supposed" replacement.

 

[Dana67Dart]

Al I can say is look at the graphs.
Post 4
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