2009 Autosleeper Warwick ( 2.2 Boxer ) faulty fuel reading (1 Viewer)

[DM14742]

I was happily trundling along the M42 the other day when to my horror the fuel gauge suddenly dropped from three quarters full to empty with the flashing warning light giving it big licks. My first thought was a catastrophic leak from the fuel tank but there was no sign of anything untoward in my mirrors and the Van was happily continuing along with no other symptoms.
I stopped soon after to check things out but couldn't see anything, I fired the Van up again and low and behold the gauge worked, well it did for a while and then the same thing happened. To cut a long story short I am getting a range of readings on the gauge varying between what I believe is the correct fuel level, occasionally it shows obviously incorrect contents on the low side and progressively more occasions when it's showing totally empty.
Does anyone know if the fuel tank has a float inside that might be sticking or any other ideas would be welcome.
Thanks in advance
Edit: it seems okay initially (from cold) but gets progressively worse the longer the drive.

 

[Derbyshire wanderer]

The fuel and water gauges usually have a 5v supply so that the 12v system doesn't fluctuate due to the charging system.
Often the 5v supply is from a voltage dropper on the instrument panel.
Possibly it fails when warm or has a bad connection from the dropper to the gauge or sender unit

 

[DM14742]

The fuel and water gauges usually have a 5v supply so that the 12v system doesn't fluctuate due to the charging system.
Often the 5v supply is from a voltage dropper on the instrument panel.
Possibly it fails when warm or has a bad connection from the dropper to the gauge or sender unit

Thanks for that. I assume all this goes on behind the instrument panel and the 5v wire then goes to the sender unit at the fuel tank? Would I be likely to find it maybe with a wiring diagram or is it a case of booking it in the Garage as I'm no auto electrician !

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[tonyidle]

Thanks for that. I assume all this goes on behind the instrument panel and the 5v wire then goes to the sender unit at the fuel tank? Would I be likely to find it maybe with a wiring diagram or is it a case of booking it in the Garage as I'm no auto electrician !

Old mechanical regulators used to cause what you are experiencing but on a modern instrument pack everything works on the same regulated voltage. Unless the entire panel has gone haywire it won't be the regulator. It's most likely the tank sender failing or (quite likely) the connection to it.

 

[DM14742]

Old mechanical regulators used to cause what you are experiencing but on a modern instrument pack everything works on the same regulated voltage. Unless the entire panel has gone haywire it won't be the regulator. It's most likely the tank sender failing or (quite likely) the connection to it.

Thanks, is that inside the tank?

 

[TheBig1]

this sounds like the binnacle cluster has failed. when cartronix refurbish them they replace the gauge controllers and the leds. costs £150

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[TheBig1]

this sounds like the binnacle cluster has failed. when cartronix refurbish them they replace the gauge controllers and the leds. costs £150

 

[dave newell]

Could be sender in tank, bsi unit or instrument cluster. No way to be certain other than in depth diagnostics or fire the parts cannon at it. You need a workshop that has good diagnostics kit and a technician who knows what he's doing.

D.

 

[Derbyshire wanderer]

Thanks for that. I assume all this goes on behind the instrument panel and the 5v wire then goes to the sender unit at the fuel tank? Would I be likely to find it maybe with a wiring diagram or is it a case of booking it in the Garage as I'm no auto electrician !

The instrument panel is very complex and unless it's a simple loose connection between the panel and the sender unit in the tank you will struggle to repair it without specialist help

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[dave newell]

The sender does not feed directly to the panel, it feeds to the BSI unit which in turn drives the instrument panel. This is why I said it could be sender, BSI or inst panel but without in depth diagnostics its impossible to tell.

D.

 

[Gaston aires]

You could use a dipstick ? (like me) Hope you get it fixed.
Best wishes
Phil

 

[Pausim]

Some vehicles only take a fuel tank reading when you first start up, the fuel gauge is then adjusted as you drive by the computer monitoring engine revs throttle position etc. The symptoms here would be consistent with that set up.

I first discovered this when I was driving a Citroen that had an lpg conversion. On long runs using lpg the petrol gauge would also drop steadily but as soon as I stopped and restarted the petrol gauge would go back to where it belonged.

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[DM14742]

Could be sender in tank, bsi unit or instrument cluster. No way to be certain other than in depth diagnostics or fire the parts cannon at it. You need a workshop that has good diagnostics kit and a technician who knows what he's doing.

D.

It turned out to be a faulty micro switch in the sender.
Problem is you have to purchase the whole unit including pump which including VAT was over £300 .
My Garage didn't charge me for labour so I could easily have been looking at £500.
This is apparently a common fault and it took the mechanic the best part of a week to receive it from Peugeot.
I am going to contact Peugeot to complain, this is a known common fault and could be easily fixed with a replacement two pence halfpenny micro switch, daylight robbery Imo.

 

[dave newell]

To the best of my knowledge there is no micro switch in the sender unit, there is a pump and a float that works a variable resistor but as far as I'm aware no microswitch. I could always be mistaken though.

D.