yes , again everyone's favorite.....fuel gauge/sender

[poppa]

Hi , I looked , didn't see my answers.

I have (counting the 1 in my car) 4 sending units, 1 original.

I have a variable power source , can I set it to 5 volts to test these (an extra gauge too) or do I need the voltage limiter too??

Are the little "gears" (on the back side) adjustments ? How do they work?

Took the original apart and cleaned it. Then took a repo apart , unwound the wire and cut the plastic piece in roughly the tapered shape of the original , put it back together and it actually is pretty close. When full though , it goes to 3.5 ohms. Maybe if I had a clue.....

Like everyone else , really tired of this sh%$

[Dans 68]

5 Volts DC is fine to the gauge - the limiter is just for the 12 volt system which reduces the apparent voltage to approximately 5 VDC. As you already took one apart you should have noticed that the toothed end of the upper and lower set points are readily accessible from the back of the unit. One moves the needle on the low end of the scale, and the other the high end. Adjust as needed. Use a small screwdriver.

Dan

[poppa]

Thanks for the quick reply/picture. I did not take a gauge apart , I took a sender apart. I don't suppose I could reach the gauge adjustment while it's in the dash

[birdsandbees]

The gauge adjustments are only there to set zero and full on the gauge. You can use a 10 ohm resistor between the sender terminal and ground to set the needle at full.

Adjusting these will not make up for the generic crap linear rheostats in most repro sending units, that don't give correct level readings. You should have 10 ohms on the sender in the full position and 70 empty. OE's where NOT linear in resistance on the sweep to get accurate 1/4, 1/2, 3/4 readings.

[poppa]

Thanks b & b.

I have an original , is anyone , good , restoring/rebuilding these? Cost ?

[A383Wing]

Adjusting these will not make up for the generic crap linear rheostats in most repro sending units, that don't give correct level readings. You should have 10 ohms on the sender in the full position and 70 empty. OE's where NOT linear in resistance on the sweep to get accurate 1/4, 1/2, 3/4 readings.

I wonder if this is why my shop is having issues trying to get an accurate reading with a repro sending unit from Classic Industries. I have 9 & 73 ohms on the meter at full & empty

The gauge reads fine with sender out of the tank, but when sender is in the tank, and about 8 gallons of fuel is added, the needle is barely above empty when it should be reading around 1/2 tank (It's not a Charger tank, it's a 16 gallon A-body tank)

[birdsandbees]

Empty / full ohm readings are probably good, it's the in between that's no good on repro's. Because the floats sweeps in an arc the original rheostat was not linear in ohm change to get correct readings.

I was very careful in how I set my sender up and similar to yours it probably took 7 gallons to get it a hair above empty, from a totally empty/dry tank state. I figure at least 3 gallons stays in the tank if you started sucking air on the intake, so not that far off reality when the engine starts to sputter. I haven't filled to see if I get a true full reading yet.

[A383Wing]

Thanks for your input, I printed out this conversation and I will take it up to the shop and figure out what to do next.....he ordered another sender thinking it's gonna solve the problem.....I have my doubts......

Bryan

[poppa]

I wonder if this is why my shop is having issues trying to get an accurate reading with a repro sending unit from Classic Industries. I have 9 & 73 ohms on the meter at full & empty

The gauge reads fine with sender out of the tank, but when sender is in the tank, and about 8 gallons of fuel is added, the needle is barely above empty when it should be reading around 1/2 tank (It's not a Charger tank, it's a 16 gallon A-body tank)
[/quote]

Now that you say that , I remember when I bought the one in my car now , I tested it and out of the tank it was right (or close) and when it was in I was swearing and cussing and throwing sh#%

[poppa]

Anyone try one of these ?
www.yogisinc.com/index.cfm/page/ptype=product/product_id=16424/category_id=3725/mode=prod/prd16424.htm

[303 Mopar]

Is it possible to bend the rod attached to the float so it reads more accurately?  Maybe close to a 45 degree bend would help?

[Staxbro]

I can't see why not. It works in any other application where float height needs adjustment... A Toilet cistern is the obvious example....

[poppa]

If I understand the problem correctly , you would just change where the ohm problem is. Inside the sender is a board wrapped in wire ,(a "nub" rides on it connected to the float arm) , about a half inch wide ,the old ones have the same thing but about half the distance the board tapers down to maybe a 1/4 inch wide , this coupled with the size of the wire , number of wraps per inch increases or decreases the resistance. My guess , almost no knowledge about how it works actually.

[b5blue]

  Like you say, I'll bet many do not consider the shape of the tank and it's angle of placement to level ground. The shape of 1/4-1/2-3/4 volume of fuel is not linear to the arc of the gauge arm, that would be why the resister tapers or the winding's spacing varies. Now add rake, the nose down stance many prefer and calibration worsens.
For 24 years I've just just put gas in when low and used the odometer and a "mental mark" on the gauge to calculate that my gas mileage has and will suck. The only time my 440 ran out of gas was when my fuel pump quit. 

[Ghoste]

True, but there is being a little off because of a cars stance and then there is unacceptably and wildly off that the repro senders give us.   Even with the stance we often prefer, there is no resaon a sender should say half full when its drooling out the filler neck and then plunge from 1/4 tank to empty in 5 miles.  Or whatever crazy variation thereof.  A little off?  Sure.  But what they are giving us is not.

[Dino]

Here's what I did to make the gauge read correctly. I did this on my workbench. I marked the float arm at full, empty, and middle. Ohms were roughly what they were supposed to be from the factory. I then took my fuel gauge out of the dash and hooked it up to the sender through the RVE limiter. I then position the float in each position, gently tweaking the gauge until it was spot on. Middle should be dead accurate, empty and full will be just past the mark, as it should be. Installed everything and it's been working fine ever since.

[poppa]

Dino , what sender did you use?

[Dino]

I had the stock 5/8 sender so I bought the one with the return line and transferred the original sender's resistor.