Bi-fuel fuel gauge

reggit · Jun 12th, 2013, 07:56

Just a minor issue that has just appeared on my 2002 factory bi-fuel, which I possibly might fix at some point if I can find out what's wrong and I get bored enough!

The LPG gauge has started taking ages to respond when I re-fuel, like 30+ miles to get an accurate reading. Just wondering if anyone can shed a bit of light as to the reasons?

Pete_c20 · Jun 14th, 2013, 11:33

Even from new the LPG gauge on my 2002 factory bi-fuel sometimes has been slow to respond. Sometimes it would read full immediately after filling. Sometimes it was sluggish, taking about 5 mins to read correctly. And sometimes, but not very often, it would take an age to come up, like maybe 10-15 minutes, or like you say a good few miles.

I've always thought, but never checked, that it was something to do with the damping of the tank output sensor due to the sensor being a float, and the damping smoothed the output when the LPG sloshed about in the tank?

Edited to add: I've never noticed anything that effected this sluggishness, except maybe only that it seems to happen more when filling from empty.

SteveV40 · Jun 16th, 2013, 21:32

My experience on my 2002 V40 are similar to yours Reggit and Pete, with the gauge taking some time to register "full". In fact, the only time it goes full straight away is when the pump cut off doesnt work properly and I overfill it (just a bit!). Pumps vary hugely in my experience, and the cut off point can vary a lot. Maybe part of the reason is due to temperature stabilisation after the fill, but I am only guessing there. I have just become used to seeing the gauge start at about 8/10 full and progress to full after 15 minutes or so, although not usually as far as 30 miles I have to admit. I get almost the opposite to that, with the gauge only registering downward after about 30 miles, when it moves wuite quickly. Again, I have grown used to this, and treat the gauge as a rough guide only, although I know I will get about 180 miles out of a tank on average.

CNGBiFuel · Jun 30th, 2013, 01:26

Guages measuring gas, particulary LPG at such low pressure are never going to be truly accurate so act as no better than a guide. I'm running CNG so my guage works on pressure, so need be less sensitive that yours on LPG which I think will work on a level, but still I use my trip.

Of course in the case of LPG each fil-up cut-out could be differnt to the next filling station, so you'll never really know what you've got. Sadly there they have you.

Ultimately you're guessing. Do what i do, stick a finger in the wind, and whislte a tune of your choice.

Jun 12th, 2013, 07:56	#1
reggit Premier Member Last Online: Yesterday 21:45 Join Date: Feb 2012 Location: Preston	Bi-fuel fuel gauge Just a minor issue that has just appeared on my 2002 factory bi-fuel, which I possibly might fix at some point if I can find out what's wrong and I get bored enough! The LPG gauge has started taking ages to respond when I re-fuel, like 30+ miles to get an accurate reading. Just wondering if anyone can shed a bit of light as to the reasons? __________________ 2009 Volvo V70 D5 (Polestar 225bhp) r-design 180,000 miles

Jun 14th, 2013, 11:33	#2
Pete_c20 Junior Member Last Online: Oct 25th, 2014 17:39 Join Date: Jul 2010 Location: Manchester	Even from new the LPG gauge on my 2002 factory bi-fuel sometimes has been slow to respond. Sometimes it would read full immediately after filling. Sometimes it was sluggish, taking about 5 mins to read correctly. And sometimes, but not very often, it would take an age to come up, like maybe 10-15 minutes, or like you say a good few miles. I've always thought, but never checked, that it was something to do with the damping of the tank output sensor due to the sensor being a float, and the damping smoothed the output when the LPG sloshed about in the tank? Edited to add: I've never noticed anything that effected this sluggishness, except maybe only that it seems to happen more when filling from empty. Last edited by Pete_c20; Jun 14th, 2013 at 11:35. Reason: add more info

Jun 30th, 2013, 01:26	#4
CNGBiFuel Classic P80 1999 BiFuel Last Online: Mar 6th, 2024 00:34 Join Date: Aug 2012 Location: 48mph Middle Lane M4	Guages measuring gas, particulary LPG at such low pressure are never going to be truly accurate so act as no better than a guide. I'm running CNG so my guage works on pressure, so need be less sensitive that yours on LPG which I think will work on a level, but still I use my trip. Of course in the case of LPG each fil-up cut-out could be differnt to the next filling station, so you'll never really know what you've got. Sadly there they have you. Ultimately you're guessing. Do what i do, stick a finger in the wind, and whislte a tune of your choice. __________________ Bifuel V70 Classic 1999 [The Old Grumpy in the Corner, "When I was a lad... blah, bl*dy blah."] Last edited by CNGBiFuel; Jun 30th, 2013 at 02:23.*

Jun 16th, 2013, 21:32	#3
SteveV40 Junior Member Last Online: Oct 4th, 2017 20:18 Join Date: Jul 2011 Location: Mansfield, Notts	My experience on my 2002 V40 are similar to yours Reggit and Pete, with the gauge taking some time to register "full". In fact, the only time it goes full straight away is when the pump cut off doesnt work properly and I overfill it (just a bit!). Pumps vary hugely in my experience, and the cut off point can vary a lot. Maybe part of the reason is due to temperature stabilisation after the fill, but I am only guessing there. I have just become used to seeing the gauge start at about 8/10 full and progress to full after 15 minutes or so, although not usually as far as 30 miles I have to admit. I get almost the opposite to that, with the gauge only registering downward after about 30 miles, when it moves wuite quickly. Again, I have grown used to this, and treat the gauge as a rough guide only, although I know I will get about 180 miles out of a tank on average.

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