Gas hand jumpy

-
1973dusterkid

1973dusterkid

Watch This
Joined
Jul 17, 2011
Messages
2,270
Reaction score
68
Location
Buford Georgia
Ok so I replaced my gas gauge with a new aftermarket gauge I did not replace sending unit.When I am driving the gas hand is jumpy is that normal.MY dad said it was because it is a old car and probly has a flot in the tank is that true.
 
I believe the gauge with its voltage regulator only gets intermitant voltage, like about every 2-3 seconds? that way the needle doesnt bounce with road bumps? When you fill your tank watch the needle "pulse" higher. Maybe there is a VR issue? My sisters Volvo P1800 gas gauge bounced like a vacuum gauge over bumps.
 
It might just be a characteristic of the gauge. I once put a S&W gauge in my old Landcruiser, WITH an S&W sender. That damn thing had no damping at all, and unless you were pretty much stopped it was useless. Come to think of it, it was pretty useless, anyhow.
 
its kinda settled at half a tank I think that the right reading is will just a few marks but when on a hill if read a 1/4 or 4/4 of a tank depending on the hill.
 
What you need to do is throw a gallon or two in the trunk, and actually run the car out of gas, HOPEFULLY in a level area. Then read the gauge, so you know your "MT" point
 
1973dusterkid said:
Ok so I replaced my gas gauge with a new aftermarket gauge I did not replace sending unit.When I am driving the gas hand is jumpy is that normal.MY dad said it was because it is a old car and probly has a flot in the tank is that true.
Click to expand...
All systems I know of have a float in the tank. That's how the sender knows the level of the fuel. Your "jumpy" gauge is probably due to it's design. It's probably made like an analog ohmmeter where you get an instant reading. The original guage has a winding around a bimetal strip that acted like a little heater. The more the sender grounded it's wire, the more the guage would heat up and move the metal strip. The metal strip was attached to the needle on the gauge at one end which would give you the movement needed to give a reading. The heating and cooling of the gauge was gradual so it didn't jump around like some of the live aftermarket gauges.
 
1973dusterkid said:
is there anyway to fix it like put a regulator in somewhere
Click to expand...

You might try going to Rad Shack. Try to get the largest capacity electrolytic capacitor they have that's rated 20V or more, within reason of price. It's hard to tell from their website, many of them are marked "web only." Try to get one OVER 3000 mfd. (That's microfarads)

http://www.radioshack.com/product/i...Name=Type&filterValue=Electrolytic+capacitors

Then go to the resistor box and get a wirewound resistor, the ones that are rectangular box like. Radio shack evidently calls these "power resistors." Get a 1 (one) ohm resistor:

http://www.radioshack.com/product/i...0&filterName=Type&filterValue=Power+resistors

and if not, the lowest value they have. This is simple to prevent the capacitor from becoming a "surge" when the key is turned on.

Wire the two across the terminals of your gauge, Hook the PLUS terminal of the cap to the + side of your fuel gauge, hook the NEG side of the cap to one lead of the resistor, and hook the remaining lead of the resistor to the SENDER terminal of the gauge.

Be careful to insulate everything, or extend the leads from the terminals so you can strap the package up out of the way.

This cap should provide a little bit of "lag" in the needle.

After my experiences years ago with S&W, I wish you luck
 
You must log in or register to reply here.
-

Back
Top