Faulty fuel gauge - Help needed please

Discussion in 'Fiat' started by JockandRita, Jul 18, 2010.

  1. JockandRita

    JockandRita Funster Life Member

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    Hi all,

    On our 99 Ducato based Hymer, we have recently been suffering with a faulty fuel gauge. The gauge gives readings of anything from full to empty, when the tank is anywhere from full to half. eg, having left Swansea heading for Hereford on a full tank, the gauge read just over 3/4 full. When leaving Hereford heading for Peterborough, the gauge read under 3/4 full.
    During the journey up the M5, the gauge read empty for about half an hour. When I came to stop at the traffic lights on the M6/M1/A14 junction, the gauge read just over half.
    When we refuelled near home, the 80 ltr fuel tank took 41 ltrs, and the gauge read just over 3/4 full.
    I did notice on the odd occasion, that going over a bump caused the gauge to move towards the correct reading, but would return to a false reading within a few seconds.

    In Luxembourg a few weeks ago, the gauge read empty and the low warning light was on, (oh sh##), but it only took 63ltrs at the pump. That meant that there was about 17ltrs left (almost 4 galls).

    I don't know if this is a mechanical fault, or an electrical fault, ie, resistance/bad earth somewhere. I have checked for good connections behind the fuse box, as I noticed that tapping the interior fuse box quite hard, caused the gauge to move. Also last week when I was testing out the new wiper blades, the gauge rose towards the full mark, but then backed off towards 3/4 again. I cannot access the connections at the sender unit without dropping the tank.

    As we say in Scotland, I am completely dumbfoonered, :Sad: (dumbfounded). :Wink:

    If anyone can point me in the right direction for a solution to the problem, I'd be very grateful.

    Cheers me dears.

    Jock, (and Rita, as she is quite concerned about it too. After all, it's her that will have to push the MH if we run out of fuel). :Rofl1:
     
  2. Munchie

    Munchie Funster Life Member

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    Can't hep you Jock but if it was me I would carry a can till I got it fixed. :thumb:
     
  3. DESCO

    DESCO Read Only Funster

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    The only time I had any thing like this put it down to a dodgy connection,tried all normal hard wired connections, then PC board. Running a soldering iron over joints cured the problem, but don't know which joint on board it was.

    Hope this helps.

    Dave :thumb::thumb:
     
    Last edited: Jul 18, 2010
  4. MikeandCarolyn

    MikeandCarolyn Read Only Funster

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    I'm always suspicious of fuel gauges-so I zero my trip meter when I fill up.I know I should get at least 400 miles to a tank.ergo sum :BigGrin: In my case the gauge has turnd out to be pretty accurate-for now !

    Mike.
     
  5. hilldweller

    hilldweller Funster Life Member

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    I've no idea if your is the same but one day I saw a cover on the floor in front of the passenger seat, unscrewed it and there was the fuel tank and sender.

    Thumping hard gets you close then you need some gentle tugging or prodding with a bit if stick to narrow it down.
     
  6. DESCO

    DESCO Read Only Funster

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    Was just going to say the same, only just thought of it, its a pig to get to cab carpet has to come half out, still better than droping the tank.


    Dave :thumb::thumb:
     
  7. JockandRita

    JockandRita Funster Life Member

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    Thanks Ken.

    I 'll get by with the mileometer, and refuel when it shows 500 Km, (312 mls), then I know I've still got about 23ltrs left, (5 galls).

    Thanks, I do the same.

    Thanks Brian. There are fitted carpets throughout by a previous owner, so it looks like I will have to investigate that one carefully.
    Incidentally, I did have problems with the temp gauge acting strangely, when all the lights, heater fan, and wipers were on, but since fitting the Sterling B2B and installing a new earth lead, that problem has disappeared. :RollEyes:

    Cheers,

    Jock.
     
  8. JockandRita

    JockandRita Funster Life Member

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    Update.....

    I have been out to the MH, turned on the ignition, and the gauge is reading full. I switched on several other items to cause a power drain, and there was very little effect..........this time, and neither did starting the engine have an effect.
    I then removed the carpets and the cover that Brian referred to earlier to gain access to the tank sender unit. I disconnected the multiplug next to the unit, and nothing happened. The gauge remained at the full position with the ignition on.
    No amount of tapping or banging, on or anywhere near the fuse box, had any effect on gauge movement this time either.

    I am still dumfoonered. :Sad:

    Cheers,

    Jock.
     
  9. scotjimland

    scotjimland Funster Life Member

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    Hi Jock...

    just a thought, it may be the case that the gauge reads FULL with an open circuit ..( plug disconnected ) rather than empty..

    I'm not familiar with Fiats so not sure .. but it sounds very much like a faulty sender unit ..

    good luck..hope you get it fixed soon
     
  10. jhorsf

    jhorsf Read Only Funster

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  11. JockandRita

    JockandRita Funster Life Member

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    Many thanks for the link.

    There is some good info there. It looks like my trusty WD40 and/or GT85 will be put to use, ie start cheap and work my way up. :Rofl1: I'd rather not go down the "fuel card" route unless I have to. :Sad:

    Don't worry, there won't be a problem posting the link to the Fiat forum. It's not as if it was another MH Forum. :Wink::Wink::Wink:

    Thanks again,

    Jock.
     
  12. pappajohn

    pappajohn Funster Life Member

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    same fault here Jock....first full, quarter, three quarters, half, full, or any combination of the above.

    removed the floor cover and cleaned/WD40 the connector block and its ok 99.9% of the time.

    i just ignore it now when it happens and it sorts itself out.

    i always use trip and know i get around 400 miles per tank so i can judge when i need fuel.
     
  13. JockandRita

    JockandRita Funster Life Member

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    Many thanks John,

    I'll get on to it soon.

    My thanks goes to everyone who replied. I'll let you know how I get on. Here's hoping that a quick spray will do the trick. :Smile:

    Cheers for now,

    Jock.
     
  14. JockandRita

    JockandRita Funster Life Member

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    Hi all,

    Two trips out in the MH, and half a tank of fuel later................and still not right. :cry:
    I am going to check connections behind the instrument cluster, and under the passenger's side dashboard next,..................when I've got time.

    Cheers for now,

    Jock.
     
  15. JockandRita

    JockandRita Funster Life Member

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    Faulty Fuel Gauge - All sorted now.

    Hi all,

    I am pleased to say that after removing the lower dashboard, and pulling out, tapping, and replacing each relay in turn, this appeared to have the desired effect. This time when turning ion the ignition, the fuel gauge shot over to the full mark immediately, something it has not done for sometime.
    On the road last weekend, the gauge behaved impeccably............until the point whereupon it showed that the tank would need a cash injection. :Sad: :Rofl1:

    Thanks to all those who gave help and advice. (I've now got a problem with my fog lamp warning light. See on another thread. :Wink:).

    Cheers,

    Jock.
     
    Last edited: Aug 17, 2010
  16. Mikemoss

    Mikemoss Read Only Funster

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    Just to let you know you're not alone, Jock. I've had the same fault with Bessie's fuel gauge on a couple of occasions in the past, both of which have been blessed by the automatic self-repairing feature thank goodness. Some useful hints and tips uncovered by your post though, so grateful for those should the gremlins strike again.

    Mine has/had a tendency to suddenly drop to zero, so I've resorted to brimming the tank and zeroing the mileometer so I know I can cover at least 300 miles before starting to panic.

    All part of the fun I guess!
     
  17. Johns_Cross_Motorhomes

    Johns_Cross_Motorhomes Trader - Motorhome & Accessory Sales

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    Had the same problem with a Elddis Sundancer I delivered down to dealership, thought my luck was in when I collected it with half a tank of diesel:Smile:

    Then it started changing so I put a tenners in for luck before I left, then 70 miles on it kept showing half then nearly empty so I put another fivers worth in:cry: just to be sure as I dont like driving on fumes:Rofl1::Rofl1:

    Spoke to Glenn about it and he said oh easy cure, float senders is under the carpet left hand side!

    Peter
     
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