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theoilburner

Pessimistic Fuel Gauge

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Is anyone else's Avensis as pessimistic on the fuel gauge as mine? Last night the trip computer showed zero miles range, and I carried on for another 15 miles. The fuel gauge was bouncing off empty for the last 5 miles or so. I ignored it, because I was sure that the 45 odd mpg I was getting multipled by 60 litre tank should mean a range of nearly 600 miles and I'd not quite done 500.

so, I stopped off at the first petrol station, filled up and found I could only squeeze 51 litres in, meaning there was still 9 litres left in the tank...

With the economy I was getting yesterday, I still had at least 90 miles left in it until it really was empty!!

That means the gauge is showing the red warning light with about 150 miles left in the tank, and empty at the point was there's roughly 100 miles left, bonkers!

Are Toyota *that* worried that their customers are going to run out of fuel?

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I would also like to know more about the REAL fuel remaining vs what the dashboard says.

I've only had my 08 D4D 2.0l Avensis since January, and a couple of weeks ago I had it down to single figures on the "miles remaining" indicator. This caused me to get stressed and start driving ultra-conservatively as there wasn't a petrol station for a while.

So could I really have gone on for many more miles? Was I worrying unnecessarily?

What I don't want to do is test it by deliberately running out of fuel, since this would leave me stranded somewhere, and even if I had a spare fuel can on board, I don't think it's good for the engine to allow it to run out.

So how are we supposed to know when we REALLY need to start worrying? I'd much prefer the readout to be accurate than to leave me guessing!

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Is anyone else's Avensis as pessimistic on the fuel gauge as mine? Last night the trip computer showed zero miles range, and I carried on for another 15 miles. The fuel gauge was bouncing off empty for the last 5 miles or so. I ignored it, because I was sure that the 45 odd mpg I was getting multipled by 60 litre tank should mean a range of nearly 600 miles and I'd not quite done 500.

so, I stopped off at the first petrol station, filled up and found I could only squeeze 51 litres in, meaning there was still 9 litres left in the tank...

With the economy I was getting yesterday, I still had at least 90 miles left in it until it really was empty!!

That means the gauge is showing the red warning light with about 150 miles left in the tank, and empty at the point was there's roughly 100 miles left, bonkers!

Are Toyota *that* worried that their customers are going to run out of fuel?

Same experience here. Toyota yellow light to refuel/ low fuel comes up as soon as the fuel goes below 10 liter (in mk2 not sure about others). So in reality 10 liter is the reserve. And its all for the safety of the passengers.

In case if it was lower than that, you would find many people suing Toyota on those basis.

I reckon, its always good to be safe.

My friend has Saab 9-3, and in his car the light comes up when 8 liters are remaining in the tank. Guess what, which car is more safer, if you dont have fuel pump near to you.

Remember that there are many places on the earth, where nearest station can be 40-100 miles away, especially in middle east (my personal experience).

So in those cases, you need something rigid like this to have at least 10 liter as reserve.

I saw that you are using Fuely. The advice I would give you, always fill it to full, never refil your tank when it is half empty or whatever. Thats how you will get the correct figures. :thumbsup:

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I would also like to know more about the REAL fuel remaining vs what the dashboard says.

I've only had my 08 D4D 2.0l Avensis since January, and a couple of weeks ago I had it down to single figures on the "miles remaining" indicator.

Remaining indicator on dashboard is calculated on the basis of your refils. Earlier you start refilling, lower it will go (not lower than minimum set by company)

If you reset your ECU by disconnecting the Battery (I am not anticipating it), all of your dashboard values will go to minimal.

Rely on the light which turns on when you go on reserve. That is the best way to keep an eye on your diesel.

Also dont forget that last 10 liters can be emptied by eco-driver in 60-90 miles, whereas it can be finished by racer boy in 40-50 miles. So stick with reserve light, and have some idea, how many miles you can get from rest of the tank.

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OUCH.... you really shouldn't be doing that. The bottom of the fuel tank is where all the "nasties" live. Water, contaminants and solid particles. You really don't want to be dragging these sort of things into your nice modern, extreemly low tolerance fit, fuel system which is full of shiney expensive parts all waiting for that slight scratch or water to rust effect.

It says Empty while it is not quite empty for a thrible of reasons:

To protect the modern injection systems which are fuel lubricated and can therefore sieze if you are moving when you run out.

To keep the crap at the bottom of the tank out of the fuel system.

To stop idiots actually running out of fuel.

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OUCH.... you really shouldn't be doing that. The bottom of the fuel tank is where all the "nasties" live. Water, contaminants and solid particles. You really don't want to be dragging these sort of things into your nice modern, extreemly low tolerance fit, fuel system which is full of shiney expensive parts all waiting for that slight scratch or water to rust effect.

It says Empty while it is not quite empty for a thrible of reasons:

To protect the modern injection systems which are fuel lubricated and can therefore sieze if you are moving when you run out.

To keep the crap at the bottom of the tank out of the fuel system.

To stop idiots actually running out of fuel.

Thanks for putting that up here. I composed it, but took it off from my post, as I am sure lots of people may not agree with it.

Well I would say, do not run your car, if fuel is less than 5 liters.

My personal experience, with my other car, where I had failure of fuel pump, when last few liters were remaining in the tank.

I used about 51-52 liters and get it refilled when 8-9 liters are still there. I hope this is safe.

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I think that thing about gunk at the bottom of the fuel tank is a myth.

The thing with the fuel tank seems to be common with Toyotas; If I refuel as soon as the 1-bar blinker comes on, I can just about get in 35L of fuel. The specs say mine has a 42L tank which means in theory I could do something like 100 miles :lol:

With the D4Ds tho' it is very important not to run the engine dry. You can get away with it with petrol engines, but in a diesel engine it can damage the high pressure rail and the injectors as they rely on the fuel for lubrication. :eek:

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I think that thing about gunk at the bottom of the fuel tank is a myth.

Fuel tanks are vessels that contain fuel and air. They are also very poorly insulated, so when there is an air inside a tank as the fuel level drops (Petrol or Diesel), there is moisture in that air. When you go outside and see the pleasant dew on the grass... don't forget the pleasant dew inside your fuel tank.... unless of course you went out of your way to insulate the tank against such an eventuality. Next, every time you fill you car up do you use a fine mesh strainer followed by a finer woven filter, so that only fully filtered fuel goes into your tank? If not then your putting whatever may be in the tank of the filling station "warts and all" into your fuel tank. You always find the presence of water, paint, rust, sand and grit in the bottom of fuel tanks. If there was no contamination in your fuel tank you would never have to change your fuel filter.

I don't even think myth-busters would have a problem with this one.

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OUCH.... you really shouldn't be doing that. The bottom of the fuel tank is where all the "nasties" live. Water, contaminants and solid particles. You really don't want to be dragging these sort of things into your nice modern, extreemly low tolerance fit, fuel system which is full of shiney expensive parts all waiting for that slight scratch or water to rust effect.

It says Empty while it is not quite empty for a thrible of reasons:

To protect the modern injection systems which are fuel lubricated and can therefore sieze if you are moving when you run out.

To keep the crap at the bottom of the tank out of the fuel system.

To stop idiots actually running out of fuel.

Thhis is a load of crap, and i will explain why...

Firstly, your car sucks fuel from the BOTTOM of the tank, so if there is contamination in there it won't make any difference how much fuel you have left, because the car will ALWAYS take fuel from the bottom of the tank.

Water is heavier than fuel, so if its in your tank, it will be the first thing to make its way to your injectors.

'Gunk' is actually microbialogical contamination, and this is formed at the interface between fuel and water. Thhis takes weeks/months to form, so you would have to have a good couple of litres in your tank and leave the car standing for several months for this to be an issue.

Lastly, the level of quality control on fuel these days is very high!

I spent 6 years refuelling helicopters all over the world for the RAF, and part of my job was to receipt the fuel and check its quality every 3 hours (if there was no movement of the fuel). Thhis included samples of all water filters, the tanks, and all hose ends, and weekly checks of the particle filters at the end of every nozzle.

I'm not saying that fuel forecourts send someone out every 3 hours to do the same, but considering they use a lot more fuel on a daily basis, the fuel is not sat around long enough to require this level of checks, but you can be assured that each fuel should be thoroughly tested before the driver connects his lorry to the tank.

The ONLY reason you should keep your fuel level from getting too low is to keep the fuel pump submerged so it doesn't overheat and start to break down.

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Thhis is a load of crap, and i will explain why...

Firstly, your car sucks fuel from the BOTTOM of the tank, so if there is contamination in there it won't make any difference how much fuel you have left, because the car will ALWAYS take fuel from the bottom of the tank.

Water is heavier than fuel, so if its in your tank, it will be the first thing to make its way to your injectors.

'Gunk' is actually microbialogical contamination, and this is formed at the interface between fuel and water. Thhis takes weeks/months to form, so you would have to have a good couple of litres in your tank and leave the car standing for several months for this to be an issue.

Lastly, the level of quality control on fuel these days is very high!

I spent 6 years refuelling helicopters all over the world for the RAF, and part of my job was to receipt the fuel and check its quality every 3 hours (if there was no movement of the fuel). Thhis included samples of all water filters, the tanks, and all hose ends, and weekly checks of the particle filters at the end of every nozzle.

I'm not saying that fuel forecourts send someone out every 3 hours to do the same, but considering they use a lot more fuel on a daily basis, the fuel is not sat around long enough to require this level of checks, but you can be assured that each fuel should be thoroughly tested before the driver connects his lorry to the tank.

The ONLY reason you should keep your fuel level from getting too low is to keep the fuel pump submerged so it doesn't overheat and start to break down.

Yes I am quite sure you did spend 6 year refuelling helicopters. Avgas and Avcat are produced, stored, transported and centrifuged, then filtered. This is quality controlled and to exacting and legal standard. Aviation fuel is sampled and tested at every storage point and transport point on its journey from the refinery to the Aircraft. It is also tested before from the aircraft fuel tanks before every flight. Basically if you find any contamination in aviation fuel, someone is not doing their job properly. How often do you open the test valve at the bottom of your car fuel tank, to test the fuel and drain away the water? Did I mention that I am also a Pilot?

'Gunk' is actually microbialogical contamination, and this is formed at the interface between fuel and water. Thhis takes weeks/months to form, so you would have to have a good couple of litres in your tank and leave the car standing for several months for this to be an issue.

MBG grows at a slow rate and will form from a single drop of water. Modern fungicide additives help to keep this in check, but MBG is a feisty little bugger and will eventually form in most tanks. Amongst the things it produces are fibrous growths which like to block up fuel filters, usually the black crap you see on you nice (used to be white) filter. Also it produces pitting in the fuel tank inner skin, which will eventually lead to rust spots and as the car ages this rust will also make its way to the bottom of the tank.

A lot of the issues here cover modern cars, where the long term problems with fuel storage have yet to get a grip. But it only takes one dodgy fill-up.

My car does not suck fuel from the bottom of the tank. It sucks it from very near the bottom. The volume of air in the tank holds the same amount of moisture as the air outside at the time that the air was drawn into the tank. The volume of air is smaller inside the tank than the volume of air outside the tank, however the same laws apply just on a vastly smaller scale. You will get water inside your tank from the moisture in the air within it. We are talking drops, not buckets.

The ONLY reason you should keep your fuel level from getting too low is to keep the fuel pump submerged so it doesn't overheat and start to break down

I can think of a few reasons and getting home is only one of them.

Thhis is a load of crap

And we were getting along so nicely.

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Blimey.

Game set and match perhaps......

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Wow, this thread sat silent since last August, but it's really "taken off" since I revived it yesterday! (Pun intended for you aviation-type people!)

Anyway, thanks for the insight and the (varying) opinions.

I think the general message I've taken from this is:

1. No need to panic as soon as the light comes on or the trip computer says there's only a few miles left. There will be at least 40 miles of grace to let me find a petrol station.

2. But in general, refuel at the next opportunity once the light comes on. Because if any of the risks suggested above ARE true, why take the risk?

Cheers!

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:) Looks likes the biggest risk to running a tank to nearly empty, is getting "Flamed" on here. :)

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At the risk of being shot down in flames :D any contamination like water in you tank will stop the engine very quickly whether full or empty as an example my wifes petrol car had about 20 ltrs left in the tank and I filled the tank up at a Sainsburys garage, drove away and 100 meters later the car cut out, I had the car recovered and I found after draining the tank it contained 10 ltrs of water and 50 ltrs of petrol. This also happened to a few more customers, what I'm saying here is that full or empty the contamination if water based will always be at the bottom where the fuel pump sits and be drawn into the system immediately then hopefully in the case of a diesel car be caught in the fuel filter/water separator which can be drained off later if the volume of water wasn't to large, too much would obviously stop the engine, most petrol cars don't separate the water out so the effect will be felt much faster than a diesel.

Pete.

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this supposed crap at the bottom of the tank wont always be at the bottom of the tank,say when going around corners etc it will be sloshing all over the place so just as easely being picked up aa any other time as its not getting a chance to settle.bit different when a car is stationary though.

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That's a good point Pete. I totally agree that any substantial amount of water will cause instant problems. I am talking about a miniscule amount of water, maybe a couple of teaspoons.

Tanks will have a curve or slight incline or slight sump where very small amounts of water and other interested parties can safely accumulate. The fuel pumps never draw directly from the bottom of this area but from a slightly higher point. Tanks are designed to take this into account. Although the pump may draw from where it sits. This point is never at the lowest part of the Tank.

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This subject reminds me of any car a salesman has ever driven!

Salesman (and women) have a habit of running their cars on fumes, it all comes from them getting into different cars on a regular basis and never want to put fuel in, just in case they go home in a different car tomorrow :rolleyes:

Many a time I have got into a car where the warning light has been burning your eyeballs out, only for the salesman to say "i could do 50 miles on whats left in there" :eek:

My point is...........why would you ever want to test how many miles you have left in the tank, is it worth the hassle of running out?

Lupidog: Didnt that 777 that just managed to land at Heathrow have some crud in its tanks? Seem to remember some bits and bobs from manufacture were found in the tanks. Not what you want you want on a final approach to all of a sudden find the throttles dont work :fear:

Kingo :thumbsup:

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Some years ago i a Ford capri,it had done about 30000 miles.i filled up with petrol a ESSO garage in tottenham and on the way home i was getting a misfire every now and then.i suspected fuel starvation so checked the fuel cap breather for blokage (different sytstem those days) but could not fault it.as i suspected the fuel i brought.

the fuel tank on the capri was at the back of the boot and not too bad to remove.there was a coubik mesh filter on the end of the pick up pipe that i could see was covered with something.so after draining the tank and filtering the fuel thrrough some muslin cloth i had about a pound of what appered like tea leaves.

i gave the tank a good clean out.there was no sign of any other rubbish in the fuel other than tea leaves.

the muslin filter was so good at cleaning the fuel i was happy to refill the tank with this cleaned fuel.

after this i ftted ia in line fuel filter.

the fuel pick pipe for the fuel pumps at garages are well clear of the bottom of the tank and anything in there that should not be, has plenty of room to settle and not be dispensed withe the fuel.the fuel i got at the Esso garage must have been introduced by a tanker.maybe the garage tank had only just been filled when i arrived on the forercour.

as for water in tanks,well i had 5 diesel cars over 20 od years.and every 6 months i would drein the fuel from the fuel filter into jam jar and check for water.not once have i ever found any sign of water, or for that matter no other foreign bodies.

there will be the odd case,as in my experiance,but to think your fuel tank is awash with water and debri and if you let the level get too low you are going to introduce lots of nasties into your fuel systems is far from a fact.

.

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My Parents (sadly now deceased) lived on the Isle of Wight.

One very late night some years ago we got a phone call 'Dad has been taken into hospital with a stroke'

Leaving home in Essex with less than a quarter of a tank of petrol the intention was to fill up at our local Tesco on the way (half a mile away)

You guessed it.... they were shut for maintainance!

The only garage between us and the M25 was therefore the BP station on the A13 at Stanford le Hope.... again shut (they update their tills between 1am and 3am....)

so... quarter of a tank in a 2 litre Avensis - Clacketts Lane on the M25 was the next option - paid an arm and a leg for petrol.

The moral of this story, and something I have stuck to ever since, fill up at half a tank - you never know when you could get stuck..... and half a tank will get you on most journeys and give you a choice of filling stations

:thumbsup:

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My Parents (sadly now deceased) lived on the Isle of Wight.

One very late night some years ago we got a phone call 'Dad has been taken into hospital with a stroke'

Leaving home in Essex with less than a quarter of a tank of petrol the intention was to fill up at our local Tesco on the way (half a mile away)

You guessed it.... they were shut for maintainance!

The only garage between us and the M25 was therefore the BP station on the A13 at Stanford le Hope.... again shut (they update their tills between 1am and 3am....)

so... quarter of a tank in a 2 litre Avensis - Clacketts Lane on the M25 was the next option - paid an arm and a leg for petrol.

The moral of this story, and something I have stuck to ever since, fill up at half a tank - you never know when you could get stuck..... and half a tank will get you on most journeys and give you a choice of filling stations

:thumbsup:

that makes a lot of sense.you never know when yor going to have an emergency.

its sods law it will happen at night,when most fuel outlets are closed.

use to keep a 25 ltr can of diesel in the shed for emergency use.dont know if ive still got it.would be no use in my vvti engine though.anyone wont to swop 25 lltr diesel for petrol.

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Easiest way to see how low your fuel tank can go is to lend your car to your son.

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Easiest way to see how low your fuel tank can go is to lend your car to your son.

lol No B***dy fear - they're both lunatics!!!

:yahoo:

ps - Acetip, I'm up your way this weekend - driving a steam train on the NNR....

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At the risk of being shot down in flames :D any contamination like water in you tank will stop the engine very quickly whether full or empty as an example my wifes petrol car had about 20 ltrs left in the tank and I filled the tank up at a Sainsburys garage, drove away and 100 meters later the car cut out, I had the car recovered and I found after draining the tank it contained 10 ltrs of water and 50 ltrs of petrol. This also happened to a few more customers, what I'm saying here is that full or empty the contamination if water based will always be at the bottom where the fuel pump sits and be drawn into the system immediately then hopefully in the case of a diesel car be caught in the fuel filter/water separator which can be drained off later if the volume of water wasn't to large, too much would obviously stop the engine, most petrol cars don't separate the water out so the effect will be felt much faster than a diesel.

Pete.

Informative, now I know why there is water separator below fuel filter. Pete would you like to explain in dept, what does it do, and when?

Does it work when car is switched off? or when its running?

Good to know such stuff.

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Easiest way to see how low your fuel tank can go is to lend your car to your son.

:lol: that reminded me when I used to drive my dad's car... and hardly ever filled it. :D

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Easiest way to see how low your fuel tank can go is to lend your car to your son.

lol No B***dy fear - they're both lunatics!!!

:yahoo:

ps - Acetip, I'm up your way this weekend - driving a steam train on the NNR....

dont forget your seatbelt.

its not the OLIVER CROMWELL is it.

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