1960 Fuel Gauge Resistance Riddle
12-24-2006, 06:37 PM
#1
Melting Slicks
Thread Starter
1960 Fuel Gauge Resistance Riddle
Hello and Seasons’ Greetings to one and all! For Christmas, I put a new fuel gauge sending unit in the 1960 today! Thought it would appreciate that!
Before the installation, I checked the gauge by disconnecting the brown lead and the gauge pegged on the “full side”. With the brown lead grounded to the tank, the gauge read a tad over the “E” mark. OK. At this point I’m feeling like the gauge checks out. So I proceed to install the new sending unit (Paragon #3792, not imported). All goes well with the physical installation. Next, I proceed to check resistance readings on the newly installed unit. Here’s where it got interesting, at least to my feeble senses. The sender with no leads attached gives me 33.3 Ohms. Now I’m feeling good because that matches the number given in an earlier post (http://forums.corvetteforum.com/show...php?t=1579180)! So then I hook up the ground lead [Black with orange stripe (?) (maybe a stained blackw/ white) on my car]and the resistance drops to about 19 Ohms; what the heck! Then I hook up the brown lead and the resistance drops to about 10 Ohms.
Before the new sender was installed, my gauge was reading near full. Now, with the new sender, I’m reading just over ˝ a tank. The fuel level is about 3” below the ceiling of the tank.
I should add that the reason for starting all of this was because I and the better half ran out of gas with a gauge that said we had 3/8 of a tank! She really doesn’t like it when this happens! That was after the car had spent over a year in the shop in the quest for numbers matching block and heads.
So I guess at this point, I’ll drive it and keep an eye on the fuel gauge to see what happens.
In the meantime, Merry Christmas to All and to all a Good Night!
DZ
P.S.
Any and all feedback welcome from the Corvette Forum Family!
New sender readings:
Gauge with new sender:
Before the installation, I checked the gauge by disconnecting the brown lead and the gauge pegged on the “full side”. With the brown lead grounded to the tank, the gauge read a tad over the “E” mark. OK. At this point I’m feeling like the gauge checks out. So I proceed to install the new sending unit (Paragon #3792, not imported). All goes well with the physical installation. Next, I proceed to check resistance readings on the newly installed unit. Here’s where it got interesting, at least to my feeble senses. The sender with no leads attached gives me 33.3 Ohms. Now I’m feeling good because that matches the number given in an earlier post (http://forums.corvetteforum.com/show...php?t=1579180)! So then I hook up the ground lead [Black with orange stripe (?) (maybe a stained blackw/ white) on my car]and the resistance drops to about 19 Ohms; what the heck! Then I hook up the brown lead and the resistance drops to about 10 Ohms.
Before the new sender was installed, my gauge was reading near full. Now, with the new sender, I’m reading just over ˝ a tank. The fuel level is about 3” below the ceiling of the tank.
I should add that the reason for starting all of this was because I and the better half ran out of gas with a gauge that said we had 3/8 of a tank! She really doesn’t like it when this happens! That was after the car had spent over a year in the shop in the quest for numbers matching block and heads.
So I guess at this point, I’ll drive it and keep an eye on the fuel gauge to see what happens.
In the meantime, Merry Christmas to All and to all a Good Night!
DZ
P.S.
Any and all feedback welcome from the Corvette Forum Family!
New sender readings:
Gauge with new sender:
12-24-2006, 11:40 PM
#2
Pro
Member Since: Jul 2003
Location: 1961 Red w/White coves 85,532 Original Miles
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Your Black ground wire probably isn't grounding as good as it should. I always install another seperate ground wire directly to the frame so I know it has a good ground.
Try that first and see what your ohm reading is. The next step is to take the sending unit back out of the tank and hook the brown and black wires up to it and measure the resistance while you are moving the float up and down. I have seen the sending units be flaky from the start.
Bill
Try that first and see what your ohm reading is. The next step is to take the sending unit back out of the tank and hook the brown and black wires up to it and measure the resistance while you are moving the float up and down. I have seen the sending units be flaky from the start.
Bill
Last edited by win1876; 12-24-2006 at 11:51 PM.
12-25-2006, 12:26 AM
#3
Burning Brakes
Member Since: Jun 2005
Location: Hinesville, GA & Oswego, NY
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60 fuel gauge
I recently went through a bout with the fuel gauge in the 60 I have had for 26 years,I replaced the sending unit and it read wrong like still reading a quarter full when it was empty. Before installing the new sending unit I checked the position of the gauge with the float out of the tank and it read right at both stops. I took it back out and checked the float position in relation to my original sending unit it was not even close , bent the float arm to match the original, reinstatalled and evertyhing is fine, full is full and empty is empty with a little reserve.
12-28-2006, 07:16 PM
#5
Melting Slicks
Thread Starter
More on the fuel sender for the '60.
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
12-28-2006, 07:56 PM
#6
Pro
Member Since: Jul 2003
Location: 1961 Red w/White coves 85,532 Original Miles
Posts: 705
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More on the fuel sender for the '60.
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
If you pulled the sender out of the tank and the fuel gauge operated correctly while you were moving the float up and down then you don't have a problem. If it changes when you put it in the tank then it must not be moving freely in the tank. I would put it together and drive it and see how the gauge reacts. I think you fixed it.
Bill
Last edited by win1876; 12-28-2006 at 08:14 PM.
01-02-2007, 09:11 PM
#7
Melting Slicks
Thread Starter
"I think you fixed it."
Bill,
I think you hit it on the head. The science side of me got the better of me and I rigged the sender so I could check it in the tank (see pic below). I rigged it with a piece of coat hanger (an all-American tool if ever there was one) threaded through on of the mounting screw holes so I could raise and lower it in the tank. I inserted the unit, grounded it and had the better half read the gauge as I raised and lowered the float. Sender works, gauge works, all is well on that front. So now it's "put it together and drive it and see how the gauge reacts".
Thanks to all and a Happy, Healthy New Year!
DZ
Bill,
I think you hit it on the head. The science side of me got the better of me and I rigged the sender so I could check it in the tank (see pic below). I rigged it with a piece of coat hanger (an all-American tool if ever there was one) threaded through on of the mounting screw holes so I could raise and lower it in the tank. I inserted the unit, grounded it and had the better half read the gauge as I raised and lowered the float. Sender works, gauge works, all is well on that front. So now it's "put it together and drive it and see how the gauge reacts".
Thanks to all and a Happy, Healthy New Year!
DZ
01-14-2007, 02:21 PM
#9
60 gas gauge
More on the fuel sender for the '60.
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
I installed an additional dedicated ground wire from the sender to the frame (steel bar that runs behind the top of the seats). The newly installed sender still reads 10.5 ohms and gauge shows just over 1/2 tank like the pic above. The needle does move slightly with movement of fuel in the tank.
I removed the new sender from the tank and hooked up the leads as suggested above. Gauge goes to full (but not past; i.e., does not peg) and drops to just about right on the E as I move the float through its range of travel. Resistance measures 0.5 to 29.5 ohms. The geometry of the old and new senders match pretty well - nothing very far out of whack that I can see.
The old sender pushed the gauge beyond the F but bottoms out at 3/8 tank. The 3/8 reading is where we ran out of gas which is what prompted the purchase of the new sender. It reads 11.2 - 63 Ohms across its range of travel.
The open circuit pegs (brown lead removed) the gauge to the right whereas grounding the lead to the tank still sets the gauge to just touching the E.
I'm open to all suggestions! Any other grounds I need to check? I suppose I could jumper the sender (directly to the post on the gauge; passenger side of gauge if I understand correctly). I have not been under the dash yet. Was hoping to put that off a while longer.
Thanks everybody!
DZ
01-14-2007, 04:06 PM
#10
Melting Slicks
Thread Starter
stratplus,
Yes, I used a short length of wire between the attaching screw on the sender and a spot on the metal bar behind the seat (center partition panel reinf. assy.; Sect J, Sheet 3 of the 1960 AIM). I wire brushed the frame with a Dremel and drilled and tapped a hole to take an 8-32 screw. I chose the spot shown in the photo because I could slip a metal bar between the tank and the frame. No chance to puncture the tank when the bit plunged thru. Note that the metal tube you see running across the pic is clearly an incorrect vent "hose". That'll get changed out somewhere down the road.
BTW everyone, the gauge seems to be functioning correctly. Just need to take it down into the lower end to see what happens. Thanks to all previous "posters".
DZ
P.S., If anyone sees any problems with this grounding connection, please give me a holler.
Yes, I used a short length of wire between the attaching screw on the sender and a spot on the metal bar behind the seat (center partition panel reinf. assy.; Sect J, Sheet 3 of the 1960 AIM). I wire brushed the frame with a Dremel and drilled and tapped a hole to take an 8-32 screw. I chose the spot shown in the photo because I could slip a metal bar between the tank and the frame. No chance to puncture the tank when the bit plunged thru. Note that the metal tube you see running across the pic is clearly an incorrect vent "hose". That'll get changed out somewhere down the road.
BTW everyone, the gauge seems to be functioning correctly. Just need to take it down into the lower end to see what happens. Thanks to all previous "posters".
DZ
P.S., If anyone sees any problems with this grounding connection, please give me a holler.
01-14-2007, 09:42 PM
#11
60 gas gauge ground
stratplus,
Yes, I used a short length of wire between the attaching screw on the sender and a spot on the metal bar behind the seat (center partition panel reinf. assy.; Sect J, Sheet 3 of the 1960 AIM). I wire brushed the frame with a Dremel and drilled and tapped a hole to take an 8-32 screw. I chose the spot shown in the photo because I could slip a metal bar between the tank and the frame. No chance to puncture the tank when the bit plunged thru. Note that the metal tube you see running across the pic is clearly an incorrect vent "hose". That'll get changed out somewhere down the road.
BTW everyone, the gauge seems to be functioning correctly. Just need to take it down into the lower end to see what happens. Thanks to all previous "posters".
DZ
P.S., If anyone sees any problems with this grounding connection, please give me a holler.
Yes, I used a short length of wire between the attaching screw on the sender and a spot on the metal bar behind the seat (center partition panel reinf. assy.; Sect J, Sheet 3 of the 1960 AIM). I wire brushed the frame with a Dremel and drilled and tapped a hole to take an 8-32 screw. I chose the spot shown in the photo because I could slip a metal bar between the tank and the frame. No chance to puncture the tank when the bit plunged thru. Note that the metal tube you see running across the pic is clearly an incorrect vent "hose". That'll get changed out somewhere down the road.
BTW everyone, the gauge seems to be functioning correctly. Just need to take it down into the lower end to see what happens. Thanks to all previous "posters".
DZ
P.S., If anyone sees any problems with this grounding connection, please give me a holler.
10-18-2015, 04:26 PM
#13
I have a similar problem, I installed a new sender as part of my end to end fuel restoration (necessitated by skunky old gasoline).
I measured resistance before installing, there was a difference between "full" and "empty" so I proceeded. And installed an extra ground as recommended above.
I now have better than 1/2 a tank of new fuel but the gauge reads empty - it does move up to empty when turning on the ignition switch.
Does anyone have any ideas???
Please and thanks
Howard
I measured resistance before installing, there was a difference between "full" and "empty" so I proceeded. And installed an extra ground as recommended above.
I now have better than 1/2 a tank of new fuel but the gauge reads empty - it does move up to empty when turning on the ignition switch.
Does anyone have any ideas???
Please and thanks
Howard
10-18-2015, 04:45 PM
#14
Team Owner
Member Since: Oct 2000
Location: Washington Michigan
Posts: 38,899
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I have a similar problem, I installed a new sender as part of my end to end fuel restoration (necessitated by skunky old gasoline).
I measured resistance before installing, there was a difference between "full" and "empty" so I proceeded. And installed an extra ground as recommended above.
I now have better than 1/2 a tank of new fuel but the gauge reads empty - it does move up to empty when turning on the ignition switch.
Does anyone have any ideas???
Please and thanks
Howard
I measured resistance before installing, there was a difference between "full" and "empty" so I proceeded. And installed an extra ground as recommended above.
I now have better than 1/2 a tank of new fuel but the gauge reads empty - it does move up to empty when turning on the ignition switch.
Does anyone have any ideas???
Please and thanks
Howard
10-19-2015, 02:49 PM
#16
Thanks JohnZ, problem solved. I am embarrassed to say that although I carefully tagged the wires when removing the old sender I installed them backwards - hence the always empty reading. Damn garage gremlins must have switched my tags?
