Fuel level gage misbehaving

[helston90]

So my fuel level was going down slower than usual- but having just had a new bearing on one that was dragging, new handbrake pads put on and a new air filter didn't worry too much as there was always going to be some difference- however....

I then went to put in £20 when the distance showed 80 miles left and nearly into the red, got back in, switched on and it still says 80 miles left and nearly in the red. eh?

So is the level sender serviceable? could it just need a bit of a strip down clean and rebuild? I've already had the lift pump replaced through under the rear seat (the previous owner saw to it that access could be gained from above).

When I unplug and re-plug in the wires on the pump the level drops to nothing and goes back to 80 miles accordingly so I'm happy it's not wiring/ ECU problem- maybe just float is stuck?

Any thoughts would be great.

[steve_earwig]

I didn't really need to check which engine you have, HDi fuel level gauges are a law unto themselves. I don't think there's much you can do with it and, unless yours is Siemens, the sender is part of the lift pump.

[PeterN]

Has this only occurred since the pump was replaced? If so it could be that the level sensor arm is bent, I have had problems with mine since I took the pump out only mine ran out about 5 miles after the light came on!

Peter

[helston90]

^ not really- the fuel pump was replaced approx 20k miles ago and has been spot on ever since, this is the first time it's done it completely randomly.

My mechanic who installed it said it was all one unit so wouldn't be able to work on it- and need to try a whole new (used) unit- how can I now find out exactly the type/ spec/ model to start hunting for?

[helston90]

Well my fuel light came on despite there being around 14 litres in there, so I swung in and stuck in a tenner as a safety cushion, then as soon as I hit the ignition the needle shot up to half way and a claimed 300+ miles in the tank.
I will keep an eye on it over the next few weeks and see what happens, hopefully it was just a blip- but will I even truly trust it again?

[hasler88]

Have you tried brimming the tank and running it down, don't know if it will work but that's the only thing left to do on mine (when I have a spare £100) before replacing parts or not using the gauge anymore

[benczuk]

As stated, its a HDI 'feature'. Mine does similar tricks. After a full tank, when it gets to about a 1/4 tank I often get back in to find the fuel fairies have been and filled it back to 1/2 a tank!

On the plus side though it *seems* to read ok or under when close to empty so I don't think there is much chance of it showing fuel when you have none and leaving you stranded.

[ZilogJones]

I have a similar issue - it usually works fine after filling until it gets down to about 1/3 - 1/4, then will randomly shoot back up to just under half-full. I have a Siemens version, so no lift pump.

I've seen here and elsewhere that it is down to dodgy solder joints in the instrument cluster. I can solder but not sure it's worth the hassle of dismantling the thing.

My solution: Always fill the tank, reset the trip counter, and start worrying the closer you get to 600 miles

[rwb]

Was exactly the same on mine. The extra third of a tank of free diesel was always a nice surprise

It also had a phase of consistently under-reading by about a quarter of a tank. It was a bit scary driving round with the fuel light on for days. That stopped by itself, but since then the gauge never quite got to the top.

My solution: Always fill the tank, reset the trip counter, and start worrying the closer you get to 600 miles

Yep. Fill it fun and run it to 600 miles.