Fuel gauge problem
Discussion
Had a quick search on the forum, and can't find any mention of this (other than a report of gauges showing 1/4 tank when it's really empty).
On my C5, sometimes on start-up, with a full tank of fuel, the gauge will show half full. Gradually, over 20-30 miles, it'll rise to show the correct level. If I leave the DIC on range, it'll start at around 200 miles and go up at the same rate as the gauge. Other times, it'll behave perfectly.
This site...
www.honestjohn.co.uk/carbycar/index.htm
mentions that it's a known problem, and can be overcome by using Chevron Techron.
This only started happening a couple of weeks ago. It's not really a problem, as I always zero the trip, but it'd be nice to sort it without getting too invasive. Anyone used the Chevron stuff or got any comments/ideas?
On my C5, sometimes on start-up, with a full tank of fuel, the gauge will show half full. Gradually, over 20-30 miles, it'll rise to show the correct level. If I leave the DIC on range, it'll start at around 200 miles and go up at the same rate as the gauge. Other times, it'll behave perfectly.
This site...
www.honestjohn.co.uk/carbycar/index.htm
mentions that it's a known problem, and can be overcome by using Chevron Techron.
This only started happening a couple of weeks ago. It's not really a problem, as I always zero the trip, but it'd be nice to sort it without getting too invasive. Anyone used the Chevron stuff or got any comments/ideas?
we had the problem once, driving along all of a sudden the fuel gauge read empty and all the low fuel, reserve fuel etc alarms went off, i though we had reached defcon 1 with all the alarms, well it did the same for a few more ignition cycles some times no fuel others under reading, seem to recall it being sluggish to read full after a fill up as well but then it just went away and hasn't happened since (please don't jinx it). I would definitely leave it for a while to see of it goes away, make sure your battery is charged and possibly change fuel supplyer but if you have been using the same one previously with no probs it could just be they had a bad/different batch. we didn't particularly change when we had the problem as we usually got fuel from one of two places and still do.
Not had the problem but it's a common occurence. It may be worth switching petrol supplier for a while. I've run Techron through and it didn't make much difference but it didn't harm it either. I don't use Chevron gas normally. Some members on the Corvette Forunm swear by it to fix the flakey fuel guage. This thread is worth a look as it has some pics of the offender:
http://forums.corvetteforum.com/showt
http://forums.corvetteforum.com/showt
Yep, they're all classic sypmtoms. I read that the problem was related to the sulphur content of some brands of petrol interfering with the petrol tank sensors. Most often for me was that the gauge would sometimes dive to zero from 1/4 full. It can also stick at about 1/3 to 1/4 full and stay that way till you run out, I never had that happen to me as I'm one of those who monitors the trip counter - partly out of habit due to riding motorcycles.
Of course as Techron isn't available around here another solution is needed. I used Redline's fuel system cleaner (e.g here) and found a bottle of that in the tank got rid of the problems for about 10,000 miles. I also found that Redex’s version worked, but not as effectively. I have recently followed the “don’t fill up twice in a row with the same brand of fuel” theory and haven’t had the problem for about 15,000 miles. Though I have a feeling that the problem occurred more often when I’d been using Esso and Shell fuels so have tried to avoid them too.
Of course as Techron isn't available around here another solution is needed. I used Redline's fuel system cleaner (e.g here) and found a bottle of that in the tank got rid of the problems for about 10,000 miles. I also found that Redex’s version worked, but not as effectively. I have recently followed the “don’t fill up twice in a row with the same brand of fuel” theory and haven’t had the problem for about 15,000 miles. Though I have a feeling that the problem occurred more often when I’d been using Esso and Shell fuels so have tried to avoid them too.
te51cle said:
Most often for me was that the gauge would sometimes dive to zero from 1/4 full.
Same here. Gets your attention when it happens the first time on a motorway late at night out in the boonies! Thought I must have a hole in the petrol tank as the "distance to empty" on DIC also dropped to zilch.Glad it's not just me then. Looks like the Chevron kit isn't available over here (I've got a mate who commutes to US every three weeks, but given the current status of airline security, I'll not ask him just yet), so I'll give the Redline stuff a try.
I guess the sensor must work in a different way to the old float/rheostat type from a few years ago if the contacts are exposed to the fuel itself. I had a look on the parts microfiche, but it's not clear how levels are sensed.
Thanks for the advice; if you see a silver C5 out of fuel on at the side of the road, that'll be me then.....
I guess the sensor must work in a different way to the old float/rheostat type from a few years ago if the contacts are exposed to the fuel itself. I had a look on the parts microfiche, but it's not clear how levels are sensed.
Thanks for the advice; if you see a silver C5 out of fuel on at the side of the road, that'll be me then.....
Your not alone.
Its happened twice to us and beleive it or not first time was before we attend the ASDA track day at Bruntingthorpe (last year) which I put down to putting 97 octane in tank just before, the second time was again on way to Bruntingthorpe this year for same event, but this time we did not put in 97 octane in fact we did not fill up anywhere near Bruntingthorpe. So how spooky was that and we have owned car over 3 1/2 years and thats the only times its happened.
TW
Its happened twice to us and beleive it or not first time was before we attend the ASDA track day at Bruntingthorpe (last year) which I put down to putting 97 octane in tank just before, the second time was again on way to Bruntingthorpe this year for same event, but this time we did not put in 97 octane in fact we did not fill up anywhere near Bruntingthorpe. So how spooky was that and we have owned car over 3 1/2 years and thats the only times its happened.
TW
Correct me if I am wrong but I dont think we have read the post properly. This is not about the fuel guage dropping to zero, which is a well known and documented problem and one which a number of us on the list have suffered. This is about the guage reading low and creeping up over time. I have not seen this problem posted anywhere - which is not to say it does not exist elsewhere, but that was the posted problem.It cannot be the same. The suplhur content point causes one of the two sensors to malfunction and because the computer cannot determine the balance between the 2 tanks, it drops the guage to zero as way of warning the driver; this is a deliberate design funtion by the engineers.
yellowshark454 said:
Correct me if I am wrong but I dont think we have read the post properly. This is not about the fuel guage dropping to zero, which is a well known and documented problem and one which a number of us on the list have suffered. This is about the guage reading low and creeping up over time. I have not seen this problem posted anywhere - which is not to say it does not exist elsewhere, but that was the posted problem.It cannot be the same. The suplhur content point causes one of the two sensors to malfunction and because the computer cannot determine the balance between the 2 tanks, it drops the guage to zero as way of warning the driver; this is a deliberate design funtion by the engineers.
You're right, Yellowshark, my original post was about reading low and increasing over time. I was assuming that this could have been another manifestation of the same problem.
I don't know how the DIC computer calculates the range, but would assume that it works on a voltage reading, probably the same as the reading that the gauge itself uses. It's an intermittent fault; once up at the correct point, if you turn off and on again, it'll sometimes be correct, other times not. I'll try the fuel system cleaner anyway. I don't suppose it'll hurt, one way or another.
Adetuono said:
You're right, Yellowshark, my original post was about reading low and increasing over time. I was assuming that this could have been another manifestation of the same problem.
Yes, I have had that too, I believe it is just another symptom but probably one people don't notice as much.
Pretty certain I had the funny readings, slow to read full/never getting there after a fill up, around the same time we had it do the sudden empty thing so I think it is a symptom of the same issue.
For us though it wasn’t really a persistent problem and I didn’t get around to doing anything to actively fix it other than search the web because it went away, so have just put it down to a bad batch of fuel.
Of course this is just my experience so I am not saying the OP doesn’t have a real problem with the fuel sender or gauge just that funny fuel readings are a known issue and seem to be down to funny fuel that can be fixed by going elsewhere or using additives rather than tearing the car apart to replace parts with ones of an equally dodgy design.
For us though it wasn’t really a persistent problem and I didn’t get around to doing anything to actively fix it other than search the web because it went away, so have just put it down to a bad batch of fuel.
Of course this is just my experience so I am not saying the OP doesn’t have a real problem with the fuel sender or gauge just that funny fuel readings are a known issue and seem to be down to funny fuel that can be fixed by going elsewhere or using additives rather than tearing the car apart to replace parts with ones of an equally dodgy design.
Edited by viperdave on Tuesday 12th September 10:13
Well, I've had another Google session, and apparently, this....
www.performanceoilsltd.co.uk/performance_improver_pi.html
...is recommended. I've spoken to the Amsoil rep, and he confirms that it's pretty much equivalent to the Techron. I'll order some up and let you all know whether it does the trick.
www.performanceoilsltd.co.uk/performance_improver_pi.html
...is recommended. I've spoken to the Amsoil rep, and he confirms that it's pretty much equivalent to the Techron. I'll order some up and let you all know whether it does the trick.
Is this a jinx thread ?? Having not had the problem for 2 years I suddenly had the gauge plunge to zero from 1/2 full accompanied by the usual alarm and red light !! Oh well, I needed to get some metal polish for the bike anyway so while I'm at Halfords I'll pick up some fuel system cleaner. If its of any significance I last filled up with BP in Bridgend, don't know if its the brand or whether someone's been slipping some coal in the petrol !
While I was in Halfords some thieving little git stole a chrome bar end from my motorcycle.
It was only a cheap chrome plastic thing but will probably cost £15 to replace the pair. 
While I was in Halfords some thieving little git stole a chrome bar end from my motorcycle.
It was only a cheap chrome plastic thing but will probably cost £15 to replace the pair. Edited by te51cle on Monday 18th September 17:47
adetuono said:
Well, I've had another Google session, and apparently, this....
www.performanceoilsltd.co.uk/performance_improver_pi.html
...is recommended. I've spoken to the Amsoil rep, and he confirms that it's pretty much equivalent to the Techron. I'll order some up and let you all know whether it does the trick.
www.performanceoilsltd.co.uk/performance_improver_pi.html
...is recommended. I've spoken to the Amsoil rep, and he confirms that it's pretty much equivalent to the Techron. I'll order some up and let you all know whether it does the trick.
Chucked a couple of bottles in the tank at my last fill-up a few days ago and all seems OK now. Must be magic.
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