problem with fuel gauge

[poki]

Fuel gauge is reading full whether the electrics to the fuel sender is plugged in or not , and I know that the tank isn't full.. checked sender thats is A ok , so any ideas? its a fiat Ductato multi jet 2 130 2017

thanks John

 

[mike mcglynn]

Hi Poki , same thing happened to me in previous van I had to send off instrument pod off to be repaired two day job £150

 

[GeoffnDee]

Could be worth trying disconnecting and then reconnecting the multiplug on the instrument display panel in case of a poor connection there.

 

[poki]

hmmm ok, what is the instrument pod and where is it please mike mcglynn

 

[mike mcglynn]

It’s in front of you when you are in the driving seat the speedo and all the other dials are in it on mine there were 4 screws to undo and the pod came off completely with one electrical plug to take off

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[Al-Di]

bad earth somewhere,

 

[poki]

update. sent the cluster off to cartronix they checked it and its 100% ok....so ordered a new fuel sender and fitted it this morning and still no different still goes straight up to full ...any ideas? what else it could be .

 

[2 Jabs]

As Al-Di said, bad earth.

 

[Landy Andy]

Are the wires ok as they go under the flexible floor, and recently there was a post that showed damaged wires at the edge of the access hole where they had been compressed under the fixing. It would either be a short so direct to earth, or an open circuit so wire broken. Try giving loom a bit of a pull with ignition on and look at gauge.

 

[Andacami]

You could run some temporary wires bypassing the loom. That way, you would be able to tell if it was the cluster or the sender, or the loom.

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[Manic]

My fuel gauge on a 2001 Fiat base was playing up, reading full then empty then half full then empty, I unplugged a multi connector under dash near fuse box and sprayed that with contact cleaner and that sorted it.

 

[poki]

ok cheers i try some of the things mentioned

 

[poki]

As Al-Di said, bad earth.

which earth are you on about , where would that be ?

 

[Al-Di]

which earth are you on about , where would that be ?

at the tank,

 

[2 Jabs]

I believe fuel gauges work based on connecting to earth. On a working gauge If you disconnect the wires and connect the lead to earth the gauge will read full deflection i.e. full.

One of your leads may be constantly earthed hence why it reads full all the time.

Disconnect the leads, check connections and any terminal blocks are clean and making good contact. Clean the connections on the fuel tank, sender unit and try to trace where the earth lead goes. Make sure it is making a good contact by cleaning with a small wire brush. You may well find some water or dirt is making a false earth. All connections should be clean and shiny.

You can get spray contact cleaner from toolstation.

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[GeoffnDee]

On later Fiat Ducato vans It seems that the fuel sender unit feeds a body system interface (BSI) and this then drives the instrument panel gauge, maybe this is faulty ,this can only be checked with a diagnostic reader. I found this information in an old post answered by Dave Newell, an expert , who used to be on here and answer many problems with these vans. I do not know anything about this system but it may point you in the right direction.

 

[poki]

right ok another update after putting new sender on and as i said it hadnt worked so i sand papered the 2 pins on the main unit and then checked the new sender plug and found that gaps seemed oversized in the plug sensor unit ,so i got a tiny screwdriver and closed the gap up tight pushed it on to the main sender unit and now it works perfectly fine, so even with the brand new genuine fiat fuel sender unit be aware that the gap in the plug sensor can be too wide so it doesn't give a good connection .. so there wasn't nothing wrong with my old sender, it was the same problem..anyway all sorted now..It cost me £82 for the new genuine fiat sender unit which I actually didn't need ,too late now guys job done simple but could be costly .John

 

[2 Jabs]

At least you shouldn't run out of fuel now. Glad you got it sorted.

 

[poki]

yes thats the thing isn't it when you got no idea whats in the tank..anyway finally got it sorted now after going through and checking everything else first, never mind.