my fuel guage goes up when i top up but never goes down

Talk about the 406's electrical system, what wires do what, how to add extra functionality, etc.

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NinoB
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my fuel guage goes up when i top up but never goes down

Post by NinoB »

i change new BSI to my 406, the fuel gauge will not go down! whenever i add fuel it will go up and never go down, so one day i ran out of fuel! The needle keep showing that i have quater fuel,

i used diagbox I performed the actuator test on the fuel gauge, and it did the full swoop no problem so its not the gauge and did complete cycle and it shows no problem, so i open the fuel tank and change the sander, infact i tried another sander but still no changes

Any help would be very much appreciated.
NinoB
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Re: my fuel guage goes up when i top up but never goes down

Post by NinoB »

can anyone give some help?
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steve_earwig
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Re: my fuel guage goes up when i top up but never goes down

Post by steve_earwig »

Probably not, that's a bit strange for us. HDi fuel gauges can behave a bit oddly but petrols are usually fine.

Umm, it could be a wiring fault but the new BSI would be favourite, sadly. I don't think the sender has much to do with the gauge, it tells the BSI what's going on but the BSI itself works the gauge.
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GingerMagic
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Re: my fuel guage goes up when i top up but never goes down

Post by GingerMagic »

I was going to suggest you do an actuator test but you already have, so it's not the gauge, but how it interprets the reading ....

My old 406 had a rubbish gauge, it would go down really slowly, then suddenly drop to 1/4 of a tank - in the end I resorted to using the trip computer as a guide, so as soon as I got to 450 miles I would go and get more fuel...

It's a pain in the bum.
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PeterN
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Re: my fuel guage goes up when i top up but never goes down

Post by PeterN »

Have you tried a BSI reset? I had a early C5 that I ran out of fuel on the way home from collecting it because the gauge was still showing some. I had occasion to disconnect the battery and after reconnecting it the gauge behaved perfectly.

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NinoB
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Re: my fuel guage goes up when i top up but never goes down

Post by NinoB »

i did not do bsi reset, i did actuator test and it worked perfectly, what disturbed me most is whenever i top up the guage moves, but never comes down, so i checked sedre wiring diagram, i realized that there is no direct connection from sander to bsi, i read somewhere that fuel tank has ground connection but i was wondering if there is ground connection on plastic tank and i checked i could not find anythin like that, please do check the wiring digram below if u do have any suggestions
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pet1.jpg
wiring connection from fuel tank sander to instrument cluster
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Doggy
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Re: my fuel guage goes up when i top up but never goes down

Post by Doggy »

The only ground connection is the return (-ve) terminal for the pump motor, which must be OK if the pump runs.
You could remove the pump/sender unit and manually move the float while observing the instantaneous level reading on PP2k or perhaps more easily watch the values while filling the tank.
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
NinoB
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Re: my fuel guage goes up when i top up but never goes down

Post by NinoB »

i did bsi reset, still no changes, so i open the fuel pump, and i move the sender in different points while moving it i do put the ignition on, so i realized that it does change on each point on the fuel guage on instrument panel,
i also checked the instrument parameter measurement, it shows

fuel quantity net quantity 0L
fuel level gross quantity 06L
meanwhile i have like 10L in the tank.

so i dunno what should i do next, is there any connection from fuel pump to bsi? i begin to suspect bsi, because if i actuate the fuel guage it completes the full cycle.
NinoB
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Re: my fuel guage goes up when i top up but never goes down

Post by NinoB »

Does instrument cluster have memory.. Or is there anyway i can reset it..? Was thinking maybe the fuel guage on instrument cluster is not holding memory..
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Doggy
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Re: my fuel guage goes up when i top up but never goes down

Post by Doggy »

I don't think so. I believe the BSI receives the 'raw' reading from the tank sender unit and sends a 'smoothed' version to the clocks.
You might simply have a bad connection causing the BSI to 'see' intermittent maximum readings.
Maybe you could monitor it using a DVM with a max hold function?
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
NinoB
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Re: my fuel guage goes up when i top up but never goes down

Post by NinoB »

Please what's dvm.. And how will i do it?
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Doggy
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Re: my fuel guage goes up when i top up but never goes down

Post by Doggy »

Sorry, digital volt meter. :oops:
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
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