Gas gauge off by 1/4

-
GermzD74

GermzD74

Cool Member
Joined
Dec 29, 2006
Messages
477
Reaction score
1
Location
San Diego, CA
After much frustration of having to drive my dart with a non working gas gauge, yes it now works, I took the cluster out, cleaned up all the corrosion on the screws.

But now it is off by 1/4, when the car is on it always shows it has 1/4 filled although it really only has what it marks after that 1/4 line or so.

Before doing anything silly to it, is there anyway to fix that miss reading? I want it to be somewhat accurate because the first time I drove it thinking the gauge now worked my ex boss had to go take me a gallon of gas to get to work lol

Hope I fix this, I'm chickening out traveling up to Van Nuys for the Fall Fling (if I go) with a bad reading in the gauge haha!
 
maybe just consider that 1/4 is now empty ?? I have the same issue with my Duster, after installing a new tank and sending unit .. When it's full it only reads 3/4 .. I think I just need to take the sending unit out and bend the rod again (it WAS worse) but I've learned to live with it for now ..

Good luck
 
Crap has caught itself under the sending unit arm inside the tank. The junk will not let the arm go all the way down to empty. You need to take the sending unit out, pop off the cover, clean it all out, and re install it. Add a new sock while you're at it and have the tank boiled out.
 
Mullinax is probably right. An easy way to check the gauge function is to pull the wire off the gas tank sending unit. When unhooked the fuel gauge should peg all the way to the right. Then ground the wire and that should make it go to empty. If it does this the problem is with the sending unit. Get it up on a rack and they're not hard to get out. Just make sure you run the gas down low first.
 
"When unhooked the fuel gauge should peg all the way to the right. Then ground the wire and that should make it go to empty." I am not TOTALLY sure, but isn't this backwards? sorry if i'm wrong.
 
Disconnected sender is same as off. To ground the wire would give max or over full reading. Mullinax is right about the debrie collecting in the sender. The float can drop to empty but th sweeper on the resiter board is blocked from getting there.
 
RedFish said:
Disconnected sender is same as off. To ground the wire would give max or over full reading. Mullinax is right about the debrie collecting in the sender. The float can drop to empty but th sweeper on the resiter board is blocked from getting there.
Click to expand...

Yeah... I had a pro show me first hand what happens. I believe his name is RedFish but I'm not sure.
 
You may also try a different regulator on the back of the cluster. The voltage values could be causing a calibration error as well. Make sure the cluster is grounding well also. I just cleaned the tank and sending unit on my 68 Dart and it is reading more fuel than is there too.
 
mguner said:
You may also try a different regulator on the back of the cluster. The voltage values could be causing a calibration error as well. Make sure the cluster is grounding well also. I just cleaned the tank and sending unit on my 68 Dart and it is reading more fuel than is there too.
Click to expand...
Did you open the senders electrical housing ? If so was the "scrubber" conact all there or was the end of it worn away ?
 
Thank you all for the good info! FABO members never fail to be helpful.


just got back from good ole crawling under my old woman (Dart) lol

And the sending unit being the cause is making sense...and it is the other way around when disconnected it stays to the left on Empty and when grounded it went all the way to the right passing F...

My guess the gauge is fine...

How hard is it to take the sender out having the tank on? Or should I drop the tank?

And if you may, explain what to do to take the sender out...and what is this "sock" I should replace? and one more thing, while cleaning everything up...how do you have the tank "boiled" out?

Yummy more stuff to learn!

Maybe a picture of a sending unit pointing out what I should look for to know it really is that would be sweet!
 
RedFish said:
Did you open the senders electrical housing ? If so was the "scrubber" conact all there or was the end of it worn away ?
Click to expand...

My scrubber was just a brass strap with no extra "brush" material on the end. I did put some extra tension on the strap that may have also caused part of my situation. I cant remember if empty is high or low resistance. so I may need to set it up with "open" circuit at empty.
 
fishy68 said:
Sorry for the mis-information Germzd74. I could've swore it was the other way around like a GM.
Click to expand...

Don't sweat it ;) As long as you don't tell me the red battery wire goes in the negative and black in positive...then all is good lol :toothy10:
 
GermzD74 said:
How hard is it to take the sender out having the tank on? Or should I drop the tank?

Personally I have never took a sending unit out of the tank. But I would imagine it would much easier to drop the take rather than removing it with it mounted.

And if you may, explain what to do to take the sender out...and what is this "sock" I should replace?

The sock is a filter screen that goes on the intake end of the sending unit pipe. Keeps trash out of the lines, carb, etc.. Sometimes all they need is a good cleaning but I would replace mine if it was me.



while cleaning everything up...how do you have the tank "boiled" out?

When you want the the tank clean on the inside you can take it to a radiator shop and they boil it out so the tank will be clean on the inside.
Click to expand...

..
 
I call it a scrubber. How about "rubber" for a name ? A brass rubber is just cold LOL
Anyway.. it constantly drags against a grid of nichrome resistance wire which wears the end of it away.
So now we've worn out a rubber ? :)
 
The factory service manual shows the sending unit being accessible on the front side of the tank (pointing toward the passenger seat / trans.housing). The sending unit screws in on the passenger side, front facing curved area, close to the passenger-side, rear wheelwell.

Since the sending unit is located on the forward facing (toward the transmission) gas tank panel (not the top of the tank), you do not need to remove the tank to gain access to the sending unit area.

You should be able to disconnect the fuel lines and the wires at that panel point, then simply un-screw the sending unit, and remove/replace.

Someone that has a factory shop manual might be able to post a factory drawing of the location of the A body gas tank and the location of the sending unit.
 
I removed mine with ease by just jacking up the car and setting it on stands and letting the axle hang. The only hard part was getting the rubber gasket to stay in place putting it back together because it had swollen up a little even though it was only a year old.
 
Well just took my babes stomach out a while back...(her tank)
I had to take the tank off which wasn't hard other than loosening the rusty nuts of the rusty bolts on the outer ends of the straps.

Boy look how clean she's been in the tank! I imagined everything brown and dirty. Well after examining the fuel sender...there are two things that might be the problem the second noticed being the most probable cause of the issue...

For those of you who have examined one up close, up on top of the piece that has wire wrapped all around seemed like there is a bit of corrosion where the little metal strip runs up and down reading...then I noticed that the end of the little metal strip (and I will use moparfreaks picture because it is very clear, thank you XD) well that metal end seems to have worn out to half...

So as that little metal travel up when it gets empty, I assume due to corrosion plus that metal strip being worn out by half leaving it like two little horns instead of a circle ...it doesn't read on top...

Solution...due to this being so fragile to try and repair a worn out piece...buy a new friggin sender :angry7:

Lol I'm gonna see if a bud of mine has his donor valiant still, it's a 67, yall think it's the same sender?

IMAGE_139.jpg


IMAGE_138.jpg


IMAGE_141.jpg


IMAGE_142.jpg


P5310018.JPG
 
Okay I'm going to try something...all I did is bend the little metal strip that moves up and down reading the wrapped wire...now when it goes up and down it rubs better...not sure how tight it should be though...Right now you can hear clicks when it moves up or down...is that too tight against the wires? is maybe that will make it better...who knows...
 
Well I bent the metal strip thing where circled in red so that the tip would rub better on the wrapped wires, well took the car around to waste some gas and it seems to mark under the 1/4 now...will have to fill er up with some juice and see how it goes...if all goes well no new sender needed...yay! :cheers:

sender.JPG
 
Wow that's clean! I hope mine likes that when I drop the tank.

What is that stuff in the the circle?

IMAGE_141.jpg
 
The contact end pictured above once had either a piece of nickle silver in it (like points) or had a half ball like spot stamped in it. Next time you take it out the end ring will be gone leaving 2 tiny sharp points that can snag in the resister winding.
 
You must log in or register to reply here.
-

Back
Top