Hi all, wanted to share this with you as it's been a bit of a bugger to track down but I *think* it's fixed (if not, the source is known) and it might help people with a similar issue.
In December, driving in the rain, I noticed my fuel gauge was showing '0' but without the 'low fuel' light. I knew the light works as it comes on with power, I had also topped up that evening so knew I had about half a tank.
Once I got home, it was still raining so I put it in the tomorrow problems pile!
Next morning I powered up the car and I had a fuel gauge again and it was showing the correct amount. Drove the car around for a bit, couldn't replicate the issue so assumed it was a gremlin.
Over the next few months it'd do the same thing. I'd start in the morning with correct amount of fuel but then once the car's temp readout got to about 40%, the gauge would go to 0 (with no warning light). If I pulled over and restarted, it'd work again for a few minutes, if I didn't it'd just stay at 0. At all times my car would run perfectly... well, as perfectly as an '07 plate BXE can!
As the air temperature got warmer, the 'zero point' would happen sooner. During the (British) heat of the recent months, I'd get used to <1 minute of readings before it'd zero out and not work again until the engine was cool.
Obviously this situation is fine but not ideal, so I started checking possible causes. My first route was battery off for 20 minutes and that did nothing. Then checking fuses under the dash, followed by cleaning earth points, still no change. Having seen on the Russian sites about dashboards being effected by poor relays, I even tried swapping the famous left-hand 460 relay but this didn't solve it. In my head, it seemed like an electrics issue as it seemed related to engine/outside temperatures.
As you can probably tell, up to this point I was avoiding removing seats or dashboards as I knew both needed me to have good weather to do.
Finally, decided it must be something to do with the sender unit so begrudgingly removed the rear seat (just a couple of blanking trims and 4 bolts) and using the best YouTube tutorials got myself to the sender unit. I noted how the thick layer of dust was dry so at least I don't have a fuel leak!
When I removed the electrical connector, the cause of the fault became very obvious. Inside the collar that's meant to keep the electrical contacts dry was a small amount of liquid. As I have no sense of smell I couldn't tell if it was stagnant water or diesel; either way, a couple of sheets of kitchen roll with careful guiding from a small flat head screwdriver removed the liquid from the pins on the sender.
On the connector itself, it was more kitchen roll to soak up as much as I could (thankfully was on a very warm day so it was drying on it's own too) before blasting both sides with contact cleaner to remove any corrosion and remnants of water.
Once fully dry, got the connector reattached and since then (3 days) have had an accurate fuel gauge again. I am considering removing the seat and checking it again in a couple of weeks to see if the liquid is diesel somehow coming up through where the pins are, but also a big part of me it waiting to see if it goes wrong again and then working out want to do!
TLDR: Intermittent fuel gauge issues, don't be a wally and go straight to the sender unit that is (probably) easier to get to for you than on an Altea!
In December, driving in the rain, I noticed my fuel gauge was showing '0' but without the 'low fuel' light. I knew the light works as it comes on with power, I had also topped up that evening so knew I had about half a tank.
Once I got home, it was still raining so I put it in the tomorrow problems pile!
Next morning I powered up the car and I had a fuel gauge again and it was showing the correct amount. Drove the car around for a bit, couldn't replicate the issue so assumed it was a gremlin.
Over the next few months it'd do the same thing. I'd start in the morning with correct amount of fuel but then once the car's temp readout got to about 40%, the gauge would go to 0 (with no warning light). If I pulled over and restarted, it'd work again for a few minutes, if I didn't it'd just stay at 0. At all times my car would run perfectly... well, as perfectly as an '07 plate BXE can!
As the air temperature got warmer, the 'zero point' would happen sooner. During the (British) heat of the recent months, I'd get used to <1 minute of readings before it'd zero out and not work again until the engine was cool.
Obviously this situation is fine but not ideal, so I started checking possible causes. My first route was battery off for 20 minutes and that did nothing. Then checking fuses under the dash, followed by cleaning earth points, still no change. Having seen on the Russian sites about dashboards being effected by poor relays, I even tried swapping the famous left-hand 460 relay but this didn't solve it. In my head, it seemed like an electrics issue as it seemed related to engine/outside temperatures.
As you can probably tell, up to this point I was avoiding removing seats or dashboards as I knew both needed me to have good weather to do.
Finally, decided it must be something to do with the sender unit so begrudgingly removed the rear seat (just a couple of blanking trims and 4 bolts) and using the best YouTube tutorials got myself to the sender unit. I noted how the thick layer of dust was dry so at least I don't have a fuel leak!
When I removed the electrical connector, the cause of the fault became very obvious. Inside the collar that's meant to keep the electrical contacts dry was a small amount of liquid. As I have no sense of smell I couldn't tell if it was stagnant water or diesel; either way, a couple of sheets of kitchen roll with careful guiding from a small flat head screwdriver removed the liquid from the pins on the sender.
On the connector itself, it was more kitchen roll to soak up as much as I could (thankfully was on a very warm day so it was drying on it's own too) before blasting both sides with contact cleaner to remove any corrosion and remnants of water.
Once fully dry, got the connector reattached and since then (3 days) have had an accurate fuel gauge again. I am considering removing the seat and checking it again in a couple of weeks to see if the liquid is diesel somehow coming up through where the pins are, but also a big part of me it waiting to see if it goes wrong again and then working out want to do!
TLDR: Intermittent fuel gauge issues, don't be a wally and go straight to the sender unit that is (probably) easier to get to for you than on an Altea!
