PDA

View Full Version : Fuel gauge sending unit (adjust)



MagikDraggin
03-11-2007, 02:38 PM
Ok, nice weather today...took the Hawk out and purposely ran it out of gas just to see how far the dash gauge was off; (it ran out of gas on me while driving it home from Canada, even though the gauge was nowhere near 'empty').

This time, the dash gauge read 1/4 tank still remaining. So I presume I can make a simple adjustment to the sending unit in the tank. Question is, which way do I adjust (read that as "bend"), the float rod...up or down?.....and if anyone has actually had on-hands experience with doing this, how far would you suggest I bend it?

Thanks,

Karl

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/62StudebakerGTHawk1-small.jpg
1962 GT Hawk 4sp

parky
03-11-2007, 04:06 PM
I can't tell you how far to bend it, but can offer a trick I just learned. In troubleshooting the gauge and sender that the po installed in my Hawk, I found them to be mismatched. I bought the right combination and had to adjust the sender. I started with an empty tank. While the mounting screws were still out, I wrapped a length of flexible copper wire around the float arm. I then threaded it up through the empty mounting holes and put the sender in position in the tank. I could then pull up on the wire and simulate a full tank when the float hit the top of the tank. I then let it drop to the bottom and found where it read when it hit the bottom. I then pulled the sender out, did my adjustments and put it in again. I decided where I wanted "E" to really mean empty. When I was happy with the results, I unhooked the wire and put the mounting screws back in place.

62 GT Hawk

MagikDraggin
03-11-2007, 05:04 PM
quote:Originally posted by parky

I can't tell you how far to bend it, but can offer a trick I just learned. In troubleshooting the gauge and sender that the po installed in my Hawk, I found them to be mismatched. I bought the right combination and had to adjust the sender. I started with an empty tank. While the mounting screws were still out, I wrapped a length of flexible copper wire around the float arm. I then threaded it up through the empty mounting holes and put the sender in position in the tank. I could then pull up on the wire and simulate a full tank when the float hit the top of the tank. I then let it drop to the bottom and found where it read when it hit the bottom. I then pulled the sender out, did my adjustments and put it in again. I decided where I wanted "E" to really mean empty. When I was happy with the results, I unhooked the wire and put the mounting screws back in place.

62 GT Hawk


That's great! Although I don't understand what it is that is actually adjusted and in what direction is it adjusted to compensate for a gauge which indicates I still have a quarter of a tank of fuel left, when in fact it is empty.

I'd like to try your idea, but I just filled the tank back up.

Guess, I just go outside and pull the sending unit and have a looksee for myself and then make an "uneducated guesstimate".

Karl


http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/62StudebakerGTHawk1-small.jpg
1962 GT Hawk 4sp

parky
03-11-2007, 05:59 PM
The sending unit I replaced it with had an adjustable arm. There was a shaft with a set screw and you could make it longer or shorter. Bending might be necessary as well if the angles aren't right. I don't know what the stock sending unit looks like, as I have no idea if the po replaced it and I was looking at an aftermarket one. What he put in there had an adjustable arm, so I assume it was not factory stock. I do know that you only need about 5" of travel from full to empty, as that is about the height of the tank.
You can take the sending unit out and put an ohm meter on it to see how it registers full to empty. Someone on this forum might be able to speak for the factory senders and their ohm readings better than me.
Once you have it out, you can also hook it up to your sending wire and then hook up a ground to the body of the sender. Then you can work the swing arm up and down and watch your gauge to see for yourself. The concept will become much clearer at that point.

It has also been suggested that the sender should be mounted pointing to the side to help compensate for sloshing.
62 GT Hawk

KGlowacky
03-12-2007, 05:40 PM
My guess is you bend up. Again that is my guess. "Logic". If you are empty and it shows 1/4 That means the float is resting on the bottom of the tank and the ohms the gauge is recieving is making the gauge read 1/4. Beding up will allow the float to fall father down and should change the ohms in the correct direction. My free advice. Report back. Good Luck

studebaker-R2-4-me
03-12-2007, 10:09 PM
Karl,

The sending unit is 46 years old. The principal it works on is a reostat whereas an arm moves across a coil of wire and gives different voltages back to the gauge. When the coil melds into a solid mass of copper along sections of the coil it no longer give the gauge different voltages but a common voltage. In other words the sending unit is worn out. The arm with the float has gone up and down too many times with empty and full tank of gas. Save yourself any more headaches and buy a new one. I just bought an NOS one from Dennis Lambert (SASCO) at the York Swap meet for my 64 hawk. I too ran out of gas and never new when or where it was going to happen next. I recently pulled my gas tank and had it cleaned, welded a 1/4" Vapour lock drain line in and sealed. I am good to go for another 35 years with out a worry.

Allen
http://i122.photobucket.com/albums/o278/studebaker-r2-4-me/Hawk.jpg

1964 GT Hawk soon to be R2 Clone

MagikDraggin
03-12-2007, 11:16 PM
quote:Originally posted by studebaker-R2-4-me

Karl,

The sending unit is 46 years old. The principal it works on is a reostat whereas an arm moves across a coil of wire and gives different voltages back to the gauge. When the coil melds into a solid mass of copper along sections of the coil it no longer give the gauge different voltages but a common voltage. In other words the sending unit is worn out. The arm with the float has gone up and down too many times with empty and full tank of gas. Save yourself any more headaches and buy a new one. I just bought an NOS one from Dennis Lambert (SASCO) at the York Swap meet for my 64 hawk. I too ran out of gas and never new when or where it was going to happen next. I recently pulled my gas tank and had it cleaned, welded a 1/4" Vapour lock drain line in and sealed. I am good to go for another 35 years with out a worry.

Allen


Wow! Nice looking Hawk you have there, Allen. Mine still has the (I think) factory Acrylic Lacquer finish on it. I've been working on (amongst other things) bringing the finish back to as close to its original luster, but it isn't even close to the shine that yours has. I am definitely humbled.

Anyway, according to the previous owner, he recently installed a new sending unit and hinted that it "might be a little off". Heh, it's a little "off" alright!

Right now, I got a full tank of fuel, which I either have to drain some off or go out and take a nice long cruise, so I can access the sending unit without spilling gas all over the place.

I'll attempt the "bend the float up a little" and see how that affects the dash gauge accuracy.

I see where you mentioned 'vapor lock'. Are these vehicles prone to vapor locking in the heat? Isn't that usually the result of too much heat around the vicinity of the incoming fuel line?

Thanks for your response.

http://img.photobucket.com/albums/v147/MagikDraggin/Other%20Stuff/62StudebakerGTHawk1-small.jpg
1962 GT Hawk 4sp

studebaker-R2-4-me
03-12-2007, 11:36 PM
Karl,

Vapour lock is nothing you have to worry about. R1 and R2 supercharged engines have a glass fuel filter bowl with a vent to avoid vapour lock which drains back to the gas tank. I am converting my Hawk into a R2 SuperHawk Clone. I only mentioned the vapour lock drain since it was one of the many items I have been working on today. I will be painting my gas tank tomorrow installing the new sending unit installing the tank and hooking up both the drain line and fuel lines to the freshly sealed tank I had done at a local rad shop.

1964 GT Hawk soon to be R2 Clone

parky
03-13-2007, 05:03 AM
Keep in mind that all sending units do not give the same ohm readings. Chrysler is different than Gm and Ford is also different. If the po replaced it with a mis-matched sending unit this will give a faulty reading. The new sender must match the gauge.

62 GT Hawk