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fuel gauge

healeyboz

Jedi Knight
Offline
So I got a fuel gauge back from Nisonger and hooked it up. Now it moves, but it reads 1/2 tank when the tank is empty. Thoughts? Sending unit grounded? Do different gauge wires in line make a difference?
 
healeyboz said:
It is a BE. The tank is mounted, but has to come back out for paint.
Ok, when the tank is back out, check the sender out good. Make sure its around 0 ohms when at the bottom and 70 ohms when full. If thats ok and the wring is decent then the gauge needs adjustment. I did a couple for Jack and they can be a PITA to get right. The ideal would be to have both the sender and the gauge off the car and calibrate together. I could do this for you sometime,if you have the time. Maybe this winter or something. Check to see if one of two movable coils might be loose on the back in shipment or something. 1/2 tank should be 35 ohms from the sending unit.
 
I think the sending unit must be messed up or something. It is all new with the resto. I have fitted everything back into place before painting and finally got around to sending the gauge off to Nisonger for reconditioning. They have dabbed a bit of paint on the adjustment screws to mark their settings. They haven't been broken. I believe the issue is in the sending unit. How can I test the sending unit by itself, taking the gauge out of the equation. I have to drop the tank before painting, can I take the sending unit out and test it by itself?
 
You've got the wrong Sending Unit in there. They vary depending on the year of the Spridget. Gauge needs to match the sending unit. Somewhere I've got a list of Sending units by year of car but cannot find now.
 
Thanks. I called Nisonger. Sounds like I need to test the sender and go from there. They said that they have had many problems with the sending units from Moss. Don't know where to go from there. Supposedly, the gauge has been calibrated to work with the 59 sending unit. So, I am thinking to:
1. check the sending unit
2. check the gauge wiring running to the sending unit.
3. check back here.
does this sound right?
Have many others had problems with Moss' sending units?
 
Hey Kim,
I will probably drop the tank later this week. Am I correct in thinking that testing the sending unit would be to hook the positive lead of the ohm tester to the sending "lead to gauge" and the negative lead to the "body" of the sending unit?
 
If you are measuring resistance (ohms) it doesn't matter. It should read the same with the leads either way. Don't fool with it much. Look, I have had my midget off the road a long time. This is the best time of year to be driving one IMHO. I would keep it on the road and drive it until its too cold to fool with and then take it down. Just fill it up and use the trip meter on the speedo to keep track of miles and about how much gas used. When its real cold outside then you can drop the tank and work on it in the garage. If you can't get it trustworthy then send it to me and I will calibrate them together and send it back. All it will cost you is the shipping. There seems to be some variation in all the senders when they get used a while. I just hate it. It ends up showing you still got some gas in the tank when its empty. That was the problem with my 71. I like for my fuel gauges to be at least right on the low end. I'm not too concerned if it doesn't read quie full when the tank in topped off, but if it is above the E mark then it should always have fuel. Those tanks are small to begin with.
 
Thanks Kim. I agree about this time of year being the best time to drive!! I wish mine was ready to go. I have been waiting for my body guy to finish up a few projects to finish mine. He is finally working on mine. I should of done it myself!! That has been the debate for a few months. I have done enough cars to HATE bodywork. So once he said that he would like to finish the car and gave me a price I couldn't refuse to finish and paint...... Oh well, off it is!!
 
I did this very job myself only a couple of weeks ago, because mine was behaving erratically. By some miracle the 48-year-old sender unit in NCBugeye is completely rust and corrosion free, as is the inside of the tank. The sender worked perfectly (0 - 70 ohms) when removed from the car.

I was at a loss until Spritenut gave me a priceless piece of advice when he suggested what he does is to add in a short (2 feet or so) ground wire attached under one of the sender unit's screws and the other end firmly attached under a screw directly up into the underside of the boot floor somewhere (preferably out of the way so no sharp point sticking up into the boot space). I chose close to where the fuel filler pipe goes through.
 
I have been saying that exact same thing before sending off the gauge to have reconditioned. It needed it--looks like new, however, that will be an option when I put the tank back in. After I check the sending unit.
 
My new GT reads 1/2 tank when full.
And the speedo isn't working.
I need one or the other, neither one makes it a little difficult to 'gauge' my fuel usage. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
Ok,
The sending unit reads at 14 ohms when empty and around 100 at full. Obviously a huge problem. I was able to hook the sender up and watch the gauge. The problem is in the sending unit. I reads at 1/8 of a tank when empty and is incorrect as it goes towards full. Is there anyway to adjust the sending unit or is there a supplier that has a GOOD sending unit. I don't remember who I got this one through.
 
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