Temperature sending unit problem.

Slant 6 Engines

  1. 68_Valiant_Wilson

    68_Valiant_Wilson Active Member

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    Here is the old and new units together. The old unit is the only one that has any sealant on it I can tell. The arrows point to where it looks like there is sealant on it. Some of you are saying it’s my gauges. Like I said the gauge just sits at C with the new unit.

    253921AA-A7C5-423C-A2EA-0513F1FD854D.jpeg
     
  2. slantsixdan

    slantsixdan =..=

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    Have you verified continuity and near-zero resistance between the two ends of the wire that runs from the sender to the gauge?
     
  3. Dana67Dart

    Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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    I will bet the cost of the sender that the problem is NOT the sender.

    This is normal, thermal gauges react slowly

    This is normal thermal gauges react slowly

    This is NOT normal.

    This is NOT normal if the car is at temperature

    I believe it has been stated that the gauge and OE sender worked fine. Then had an issue that the sender did not fix.

    If the fuel gauge is functioning correctly that suggests the dash voltage regulator is good.

    If no other changes were done to the car between working and not working it is the gauge.

    Just my 2 cents.
     
  4. slantsixdan

    slantsixdan =..=

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    LOLROFL, but yeah, you may very well have a faulty gauge.
     
  5. 68_Valiant_Wilson

    68_Valiant_Wilson Active Member

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    Could it be that I just got the wrong sender? Slantsixdan suggest this https://www.amazon.com/dp/B000C81UZY/?tag=2402507-20. The new one I put in was a duralast TU22. It came with no red tape on it. The picture is exactly the way it looks. The one slantsixdan suggested has no tape covering on it either. I have been told that if it doesn’t have any tape on it it will not function properly. The gauge obviously works to a certain extent otherwise it wouldn’t move at all when I grounded it. I don’t have a mopar c-3826 tester to test the gauges. I really do not want to pull out the dash to test this because I’m afraid I’ll never get it back together right. I’m really kind of clueless at this point. I have a connection when I test the battery ground and the sending wire so I’ve ruled out bad wire.
     
  6. slantsixdan

    slantsixdan =..=

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    Could be.

    Duralast = generally garbage.

    May or may not be nominally correct for the application. If so, may or may not have the correct resistance range.

    That doesn't matter.

    That's not correct.

    Odds are very good that your options are to pull the dash and fix it, or leave it unfixed. This is part of what goes with driving an old car: you eventually have to fix stuff most drivers never have to think about.

    How come? Instrument cluster removal and installation isn't terribly difficult.

    No, you aren't; you've been given lots of good clues here in this thread. Now you just have to choose to pluck up your courage and follow them.

    No, you haven't. You need to make sure there's no significant resistance in the entire length(!) of the wire that runs from the sender to the gauge. That means pulling the instrument cluster.
     
  7. Dana67Dart

    Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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    Go on ebay and buy one 75ohm 2 watt resister, one 25 ohm 2 watt resistor , and one 10 ohm 2 watt resustor. You now have a mopar c-3826 tester. Take the 75 ohm and connect it between ground and the wire that would connect to the temp sensor . What does your gauge do?. Do the same for the other residtors. Record the results and report back
     
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    • slantsixdan

      slantsixdan =..=

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      He says:

      129 ±10% ohms at 100°F
      17.7 ±6% ohms at 220°F
      11.8 ±5% ohms at 250°F
       
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      • 68_Valiant_Wilson

        68_Valiant_Wilson Active Member

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        Ok! Thanks. I’ve been looking at the wiring running to the temperature sending unit and noticed that some of the insulation is burned off. I think the wire is being grounded somewhere it isn’t supposed to be so I’m replacing the wire and seeing if the fixes anything.
         
      • RedFish

        RedFish Well-Known Member

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        if the wire was grounded the gauge would peg ( you knew that ). If it stayed grounded long enough, that would damage the gauge. I've seen this wire pinched under the slant 6 valve cover and damaged badly. If most of the wires strands were broken, that might cause your symptom.
         
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