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  1. #1
    Join Date
    Sep 2021
    Location
    Bridgwater, Somerset
    Posts
    21

    Fuel sender wiring issue

    Anyone had any issues with their fuel sender or gauge.
    Just found the earth wire melted from the sender back to the rear loom.
    Not sure if my photos have uploaded.

    looks like leg 3 of the loom. and the splice into the earth cable that feeds the rear lights.
    Lucky no other cables are damaged.

    Should it just be a short earth to the sender screw, rather than a long run back to leg 3

    Melt 1.jpgmelt 3.jpgmelt 4.jpgSplice in wheel arch.jpgSplice in wheel arch.jpgSender instruction.jpg

  2. #2
    Join Date
    Feb 2013
    Location
    Surrey
    Posts
    425
    That's been very hot indeed. My first thought is that you have a bad earth somewhere else which means other things, maybe, are all using that wire for their path to earth., overloading it. Remember that your sender is a resistor - the less fuel you have, the higher the resistance. You don't want other sytems trying to get to earth that way.
    But it's been so hot, it might be a short circuit - in which case, why haven't you blown a fuse?
    DAX Cobra. May contain nuts. Always read the label.

  3. #3
    Join Date
    Jun 2016
    Location
    Nantwich Cheshire
    Age
    54
    Posts
    422
    That looks like a short to me. Was the fuel sender working?

  4. #4
    Join Date
    Sep 2021
    Location
    Bridgwater, Somerset
    Posts
    21
    No idea if the sender was working or not, as I only just purchased the car, the gauge was showing empty, I topped it up with 5ltrs and nothing moved.
    I then put some fuel at petrol station and nothing seemed to register, which is why I went on the hunt to trace down the fault.

    First thing I found was the earth terminal on the sender which looked black and melted, then I followed the cable back and found it had melted in the split conduit
    right back to where it had been splice into leg 3 loom inside the wheel arch. The crimp on the splice looked good, the other part of the earth cable all looked good.
    So it only shorted on the fuel sender earth back to the loom.

    I will run a new earth 25amp 2mm direct back to the isolator and run it in a separate conduit, just to be safe.
    I don't fancy having it in with a bundle of cables which feed the rear lights in leg 3 of the loom.

    I cant believe it never blew a fuse, must have been right on the fuse limits.

    Next job is test the sender unit. Or just fit a new one and be done with it.
    Not sure who supplies these sender units, only info I have found is Caerbont Automotive instruments LTD
    Swansea. part number TBA9X1X 10hms empty to 180hms full or TBA9X5X 3ohms empty to 80ohms

  5. #5
    Join Date
    Jan 2006
    Location
    Chelmsford Essex
    Posts
    1,742
    I would just measure the resistance values by swing the float this should prove the float is good. Then connect it up to the 12v feed and earth it. First check you in fact have a 12v fused supply ! The fuse should of blown way before you get into insulation melting.
    The sender Caerbont Automotive instruments LTD, Swansea have ties with Smiths but that sender does not look like a Smith's.
    John Desz

    Essex & Herts Area Rep. UKCC

    Dax 351 Cleveland T5 2.88 PL

    Events posted and meeting updates follow Face Book.

    https://www.facebook.com/groups/170236225077355

  6. #6
    Join Date
    Sep 2021
    Location
    Bridgwater, Somerset
    Posts
    21
    looking on caerbont webb site it recommends these as the retailer's
    Merlin motor sports
    Demon tweeks
    Europ
    holden
    Carwood

    Looks like AK use Speedy cable for instruments

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