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About JDziark

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    Registered User


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    New York
  1. Good point on the calibration. I'm thinking of taking out the sending unit, hook it up to the gauge and manually move the float up and down to see the effect on the needle. I did put some gas in the tank and am not sure if it's above the level of the sending unit.
  2. More info. Played around with the gauge. The 'stud' that the points close again is actually threaded. I turned it in about a quarter turn to insure good contact with the other end. Putting a current to the yellow/red wire and checking the voltage at the yellow wire gives a nice variable voltage reading. I ordered some higher wattage bulbs for the dash and will wait for those to come in before hooking everything back up. Great learning experience - thanks to you guys. If anything else comes up, I'll let you know. John
  3. OK, bad contacts it appears to be. When I apply 12V to the feed (yellow/red wire) and measure the voltage of the yellow wire, it's >1V. If I apply a little pressure to the contact, it goes up to 12V. Captain, as you suggested, I'll start with a strip of paper but may eventually go to a thin piece of some kind of slightly abrasive material. I'll keep you guys posted. This whole restoration project has been a case of 3 steps forward, 2 back. Now I have to fix the gauge and then put everything back together again. Do either of you have any tricks up your sleeve to reattach the cable goi
  4. Steve, thanks. I'll wait for your video. In the mean time, I'll work at removing the gauge. I could just keep the tank full of gas but the thing not working is annoying. John
  5. Captain, great input! Thanks. I probably measured the resistance wrong, the prongs were very hard to contact with the gauge in the dash. I wondered if the regulator switch was like a set of points. Imagine how many times that switch turned on and off over the last almost 50 years! I've gone this far and will continue and take out the gauge. It will be a lot easier to work on. Is that picture (very helpful, thanks) taken from the front of the gauge? If so, how do you get the needles/faceplate off? I'm the original and only owner of this car, it's been a long process to refu
  6. Captain, a little more data. 1). When I back fed the gauge with a 12V source (momentarily since I didn't want to burn anything out), the needle behaved normally. 2). I bit the bullet and took the dash half apart to get at the back of the gauge. The yellow wire on the back of the gauge reads < 1V, the same voltage I get all the way back to the yellow wire at the tank. 3) The yellow/red wire appears to be the feed. No voltage when the key is off, 12V when the key is on. 4). I got about 700 ohms between the yellow and yellow/red wires at the gauge (after pulling the harn
  7. Ok, thanks to both of you for the input. Looks like I have my work cut out for me. Not sure when I'll get to it. I may save it for next winter's project. I'm in upstate NY so there will be plenty of time to work on it then. Thanks once again for all the valuable input. John
  8. Steve, thanks. To answer your previous question, the other gauges work fine so it looks like it is a fuel gauge issue. I did review the FSM on gauge removal but it still doesn't look like a lot of fun! Any particular reason why I shouldn't back feed the gauge? Thanks for you comments. John
  9. Fantastic, great help and your explanation makes sense to me. Looks like I have to remove the gauge - something I'm not really looking forward to! I'm thinking of trying something. See if this makes sense to you. How about if I back feed a 12V source at the yellow wire by the Sender Unit? That should send current through the 'Second Heating Coil' and the 'First Heating Coil' then to ground. Shouldn't that make the needle move? Not sure what I'd do after that even if the needle does move but if it doesn't, wouldn't that mean that that one of the coils is bad (since that would not all
  10. Steve, thanks for getting back to me so quickly. I did check for continuity as well as voltage at the dash. When I first encountered the problem, I thought I might have a broken/frayed wire from the dash to the tank but continuity was good. Also, the voltage of the yellow wire at the dash is also < 1 volt. It would seem that for some reason, the source of the yellow wire (the gauge?) is putting out only a small amount of voltage. Any other ideas? Thanks again, John
  11. The fuel gauge on my 72 240z is not working. I've searched this site and have a question. Thanks in advance for any help you can offer. 1. It appears that the voltage at the yellow wire by the fuel tank should cycle between about 9 and 3 volts. I read less than one volt on that wire (it is not zero). I traced the wire back to the harness under the dash and at that point it is also <1 volt. Can someone verify that the voltage of the yellow wire by the tank does indeed cycle between about 9 and 3 volts? The yellow wire can be probed from behind the cover in the rear of the car tha
  12. I know this is an old listing. Do you still have this?
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