Fuel gauge & sender resistance issue. HELP

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Brad426

Brad426

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1969 Valiant.

I want to use my stock fuel level gauge with my after market fuel cell sender unit.

My understanding is that the stock system operates in a range of 0 to 60 ohms. Is that correct?

My fuel cell sender unit has a range of 0 to 90 ohms. Whay can I do to make it work accuratly?

Thank you
 
the original gauge needs 73 ohms for empty and 10 ohms for full. Anything less than 9.5 ohms will toast the gauge.
 
If full is too low resistance, you could add a series resistor, but of course that would add on the MT end. 'Bout all you can do...........is experiment

Can you get a coathanger, etc, into the filler so you can pull the float up/ down and measure it from MT to full?
 
67Dart273 said:
If full is too low resistance, you could add a series resistor, but of course that would add on the MT end. 'Bout all you can do...........is experiment

Can you get a coathanger, etc, into the filler so you can pull the float up/ down and measure it from MT to full?
Click to expand...

Yes I can.
 
I realize this can be a PITA, and no one I know of has found an "easy" way to calibrate repop stocker senders, either

You might be able to do this by bending/ changing the float arm. Seems to me that if you were to bend the arm so that MT is about 73 ohms, that this should also raise the full setting.

Don't forget, you probably want to put enough fuel in, to drain down to the outlet to establish "true MT" that is, you don't really want the float on the bottom of the tank.
 
67Dart273 said:
I realize this can be a PITA, and no one I know of has found an "easy" way to calibrate repop stocker senders, either

You might be able to do this by bending/ changing the float arm. Seems to me that if you were to bend the arm so that MT is about 73 ohms, that this should also raise the full setting.

Don't forget, you probably want to put enough fuel in, to drain down to the outlet to establish "true MT" that is, you don't really want the float on the bottom of the tank.
Click to expand...

I waz thinking that very thing. Yesterday with the help of my assistant, before the beer. I powered up the car, made sure the tank was grounded, & touched the stock sender wire (Purple) to the GM sender unit. Nothing. So I have to double check the wires again. Stand-by one.
 
OK back at it. I screwed the insturment cluster to the dash frame. I have a ground from the batter direct to the sender unit. The fuel tank is almost full.When I turn the key on the wait. The needle creeps up just a bit below the "E". At least I have a signal. I took a coat hanger and forced the float down. The guage went upto and past "F". Seen backwards to me. When I let the float up. The gauge returned to the "E" position. I pulled the new sender unit.

It read 5.5 ohms at the all down (Empty) position. It reads 91.4 ohms in the full up (Full) position.

WHAT's THE FIX?

Thanks All
 
The sender goes the wrong way for a Mopar gauge. Time to contact the cell manufacturer and see if there "is" a fix

I know Redfish works over those gauges. Maybe he can reverse the gauge movement?
 
Just a first thought.

Brad426 said:
I don't think that is a good idea. Because the sender unit ground is part of the housing and is screwed to the tank.....It's super grounded. Just a bad idea but, thanks.....
Click to expand...
 
General thought.... Not having a picture of your fuel cell... Can the sending unit be rotated 180 degrees? That should change the readings to where you need them if I am thinking correctly.
 
This would have to be a change in the resistance unit mount, not just rotating the sender in the tank mount. Any way you slice it, Mopar senders DECREASE resistance as the float comes up

Can you post a photo of the sender?

Link to the destructions, or at least who made it?

Damn, buddy you don't deserve this kind of frustration
 
Nothing can be done to change the gauge operation so it works with that sender.
I could make that sender match the gauge if there is no other option.
 
67Dart273 said:
This would have to be a change in the resistance unit mount, not just rotating the sender in the tank mount. Any way you slice it, Mopar senders DECREASE resistance as the float comes up

Can you post a photo of the sender?

Link to the destructions, or at least who made it?

Damn, buddy you don't deserve this kind of frustration
Click to expand...

Explain where I am missing this to me, I know I am thick headed sometimes and can't see the forest because there are too many trees in the way, LOL. If you push the float to the bottom it reads 5.5 ohms at the all down (Empty) position. It reads 91.4 ohms in the full up (Full) position. If the complete sending unit was rotated 180 degrees (assuming that the fuel cell has the sending unit mounted in the side like the a body Mopar do) you would It read 91.4 ohms at the all down (Empty) position and 5.5 ohms in the full up (Full) position.
 
The factory gauge would show empty at 73 ohms which would actually be more than a quarter tank for that sender. Then at full or anything less than 9.5 ohms the factory gauge would die.
 
Oklacarcollecto said:
Explain where I am missing this ------------------ has the sending unit mounted in the side like the a body Mopar do...............
Click to expand...


That would be right in theory, but most fuel cells I've seen (no expert on 'cells) had the fill/ sender/ etc ports on top. And, it just might be that the bolt pattern/ etc fastener for the sender (if on the side) would prevent you from turning it upside down.

And of course you'd have to rebend the arm

That is part of the reason I asked Brad for a photo/ brand/ part no/ etc of the cell/ sender
 
67Dart273 said:
That would be right in theory, but most fuel cells I've seen (no expert on 'cells) had the fill/ sender/ etc ports on top. And, it just might be that the bolt pattern/ etc fastener for the sender (if on the side) would prevent you from turning it upside down.

And of course you'd have to rebend the arm

That is part of the reason I asked Brad for a photo/ brand/ part no/ etc of the cell/ sender
Click to expand...

HMMM, this may be a market for some company to explore. I am like you my knowledge of fuel cells is very limited. When I grew up the poor boy way to have an aluminum fuel cell was an aluminum beer keg and convert it.
 
I decided to improvise. I bought a stock sender unit from NAPA for $60.00 and made one unit out of the two. One thing to keep in mind is that the brass pointer needs to be removed and sodered on after. You need to take picture or notes on it's location. I next made a full scale drawing of the 10" deep fuel cell to cut and sender float arm and check the range of the arc. I also needed to establish the location of the sender unit to get full swing and reach the stops. Soder in place. Next I checked the calibration. I adjusted the float arm stops so the gauge needle was "bang on" in the dash. I had to disassemble the the top of the unit so I could install it into the tank through the fill hole and reassemble. Tested again & Bob's your uncle, Tout fin! O:)

I want to thank my Dad (now passed away) for giving me he brains to look at problems in a different way. Growing up on a farm made me learn to be resourceful. Have you tried welding with two 12 volt truck batteries, jumper cables and a coat hanger.....It will get you home.
 

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!! Good goin !!

That cell mount looks a lot like what I call the "old style standard" mount.

The older Chivvies used that mount, as did my ?? 62 Landcruiser ?? and the SW gauges sender which never was very helpful, either. (The SW fuel guage is a bridge design, which SHOULD be accurate, but the meter was not damped, so the damn thing continually flopped around all over in there. I never did stop carrying extra gas for the thing.
 
Yeah the problem most seem to have now is that the autometer chrysler/ford gauges do not work with todays versions of mopar or fords fuel senders linear and non linear. I need to fix this issue on mine.
 
67Dart273 said:
!! Good goin !!

That cell mount looks a lot like what I call the "old style standard" mount.

The older Chivvies used that mount, as did my ?? 62 Landcruiser ?? and the SW gauges sender which never was very helpful, either. (The SW fuel guage is a bridge design, which SHOULD be accurate, but the meter was not damped, so the damn thing continually flopped around all over in there. I never did stop carrying extra gas for the thing.
Click to expand...

:cheers:

LOL Thanks for the flash back on fuel gauges....I had a few VW bugs over the years (still love them) and the fuel gauge was controled by a cable that went to a float in the tank. That gauge never missed a pot hole, speed bump, bump in the road or a road kill. You could calculate the G forces in a turn with the fuel guage...LOL. and use it to determine your angle when parked on a hill O:)
 
LOL Did not know that. I remember Model A Fords, my Dad had a couple when I was a kid, --they had the gauge built right into the tank that formed the dashboard and I remember the unique "spare tire" operated window washer in the bugs.

This was taken when I was about 4?. My GRANDFATHER was younger then than I am now. This would have been about 51--52

Gramps on the left, my sister, now gone from brain cancer, me, and Dad. The reason I look so depressed here is that I have just received either the first or second of one 'ELL of a spankin. Look carefully at the passenger side headlight. It's broken out.

I had asked my Dad, "how do those work?"

I believe he gave me some really silly answer like "there's a little man in there with a lantern."

WELL!! I just HAD to meet that "little man." Luckily, for me, I had a toy carpenter set, and in those days, a toy carpenter set REALLY worked. You got a REAL hammer and a REAL saw, they were just SMALL.

So I had taken my toy hammer, looked carfully for Mom or the neighbors, and bashed out the lens. Of course I had not checked throughly enough, and got caught. The thing is, I don't remember if this was the FIRST time I did that or the SECOND time, because Dad had fixed the lens quickly and I never DID get to see that "little man!!!"
 

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GREAT STORY & PIC! Wow. We need to start a flash back thread. In Ontario you had to use the windsheild washer fluid all the time in a bug. Pray you did not get a flat in slush season. Hay I got pretty good at overhauling gasoline heaters in bugs. I could melt your left knee cap.....lol. Bugs should of had CO2 detectors like aircraft do. I recall scrapping the inside of the windscreen with a bank card so I could see what I was about to hit....LOL Going to and fronm work was an adventure.............I miss that ****.

My dad had a Model T. One night he got juiced up in our small town. He drove around honking the augaaaaa horn a 3 AM. The village cop was his brother, my uncle and he made dad spend the night in jail. North Americas Smalled Jail, No ****.

http://twp.tweed.on.ca/thetweedjailhousec23.php

But, Dad went to church the next day, prayed & confessed and had a clean slate for next weekend....LMFAO!
 
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