billschroeder5842

I have a "rule of thumb" question to pose

I put a new sending unit in the gas tank of my "82 a couple of months ago. It works well but the gauge is off and I have been racking my brain how (or even if) to make the "bending the float arm" adjustments on the 24 gallon tank.

Here are the symptoms...

When full of gas, the gauge pegs and will stay above full for about 100 miles as I'm averaging about 17 mpg (go crossfire!) between city and highway.

When the gauge reads empty or at about 300 miles total distance, it requires about 18 gallons to fill leaving about 5-6 in the tank.

When I do the wooden rod "dip stick" check the point where the gauge and the tank seem to read equally is a slightly below 1/2 or if, the gauge was a clock it would apex about 11:30.

My confusion is that the readings are not "linear" meaning if it was 5 gallons off (reading high) at full it should be reading 5 gallons high at empty instead of reading 5 gallons low at empty? It seems that the float read and the gauge are not synched up?

I'm willing to take it apart and experiment with the float level to dial it in but am wondering if it is worth the effort as the readings don't seem to match.

Any idea on the "rule of thumb" bending question? if you move the arm 1/4 inch up/down it will move "X" on the gauge?

Any ideas or am I looking at this totally wrong?

(I could just leave it alone and have another beer)

'75

Seems to me, if you bend the float arm up, then that will help the full reading , but leave more fuel in the tank when it reads empty.

'75

The scale is off, or the float arm is too short, have you looked ad\t Willcox's help videos?

bj1k

Sounds just about right to me . You have about a five gallon reserve when it reads empty and it draws from the bottom of the tank , so it leaves you a safe amount of reserve to get to a gas station. If it were my car I would leave it alone and go have that other beer.

Ibanez540r

Pretty much. My '16 Ram has the 32 gallon tank in it, and I have pegged the gauge below E and the most it has ever taken to fill was about 28 gallons.

BUT, if you wanted, it would need bent DOWN to lengthen the arm closer to the bottom of the tank.

bashcraft

This. A longer arm will correct it at empty and full.

centralcalvette

I agree that the gauge is off and an adjustment MAY cure it. Just remember that as a general rule fuel gauges do not read linear. The first half a tank goes much slower than the second half. I suspect it's to give the illusion that the car isn't using as much fuel as it is. If you just spent $75 filling it up and the level seems to drop immediately, your assumption would be that it's using lots of fuel.

bashcraft

So it's a conspiracy?

jim in oregon

Bill..assuming you replaced the sending unit with the proper one..sounds like it's miller time..You know what fuel and how much you put in and your normal mileage..BE happy that when the gauge is on EGYPT..you have more than a few miled before you run out on the road.. JIM

billschroeder5842

The car advice that works in all situations

0Willcox Corvette

Bill.. it sounds normal to me... The scale for the sender to the fuel gauge was supposed to be linear (0-90 ohms with 0 being empty and 90 being fulle) but you see how that worked out. Senders will put out more than 90 ohms when full in most instances and bending the float will only cause you more issues.

I suppose you could pull the sender from the tank and connect it to the car with the arm at empty, remove the needle from the dash unit and then re-install it at exactly empty but what will happen then is you'll push even further past full when you fill it up.

IMHO,

Willcox