Help with Fuel Gauge problem...

[br14nh]

Have searched this but can't find info I need; Does anyone know how the Litres in tank is read - is it the sensor, or is it calculated from usage?? If it's the sensor, then I have a doozy of a problem...

The car (VX 1, executive manual V6 wagon) has been running normally in respect of the electrics for at least a year (haven't owned it any longer than that ); after I parked facing up a slight hill, (I knew I had a little under half a tank of juice) - when I got back in & started the car, the low fuel warning activated and display (single window) switched from "trip meter" to "distance left before empty", showing 4Kms. I went about 100 metres & pulled over, switched off completely then switched on using the "up" & "mode" buttons to get me the diagnostic info - cycled through readouts to find it was reading ~30Litres in the tank, which was about what I expected (?!?!)

The Fuel Warning was still active even after this off & on sequence; then I switched off & on to get normal display back, low warning still active, but fuel gauge verrrrrrrrrry gradually climbed back over the next 5 minutes to where it should have been..... WTF?? Haven't driven the car since, but will keep an eye on this now...

1) I would love to know why this is happening but suspect the cause won't be known...
2) How can the Litres read accurately on the display window in diagnostic mode, yet the gauge reading is screwed ?!?!?! - and then gradually changes back to what it should ?!?!?!?!?! - Hopefully a Holden Tech-savvy person can answer that one!!

I have EFI Live on my laptop which I'll be hooking up tomorrow to see what DTC's (if any) exist...

Cheers,
Brian

[KiWi1]

Could be the fuel sender. They tend to go. Was a recall, maybe you missed it?

Dont forget it is a Commodore.

Also, they pick up is at the front, so that could be a why it reads low, on the hill.

I know i had to run at least 1/2 a tank when racing, to stop fuel surge. 1.50 60' can cause many a pickup problem BOOM!!

[VryNeat]

its a sensor in the tank so when its at an angle is missus the tank and does a basic calculation same stuff happens in my mates vz when the computer trips and realizes what happened it fixes itself plus the computers r always faulty many guys on the forum r finding its way out on the digital gauge and thats in there vy's n vz's hope that kinda helps

[Snap-on]

Yeah i've had this problem in my Vt aswell. It does settle down soon after. Also when the tank is low it can have a skits sometimes

[br14nh]

Thanks all, reassuring to know.... what I still don't get though is why the gauge tells me it's empty, but the diagnostic readout says the right amount (30litres)?? - If the gauge is following the sender, how is the 30 litres being measured?

[illlusion]

Hope this explains things
the gauge has been calibrated to not fluctuate when cornering so if you had parked on a hill for a period of time when restarting the car will show less fuel as the gauge thinks there is less fuel the diagnostics is a instanced read out if you where to park in the same spot and go into diagnostics it would show about 6_10 liters on the display this also applies to adding small amounts of petrol to under 20liters wont show up right away

[br14nh]

Got it now, thanks...... from that, it seems the delay on the gauge is a bit extreme.... oh well, at least I know it's behaving "normally"... for a Commodore...

[Full Spectrum]

Just read the book, And illlusion is spot on.. Takes 10min to read because of the cornering, Thats so it wont go up and down and make it seem as though it's lost fuel fast.
It's a good idea, In the VP it can move and shock you, The VT's onwards are designed tyo not register movement cornering hills etc.