I filled the Aspire's tank a few days ago, and I went on a long drive today. The gas gauge was over the full mark after I filled it. This was a mix of city and highway driving, with speed averaging from 35 to 50 mph in and around town, and 60-70 mph on the highway. To make a long story short, The gas gauge hit the E mark at a bit over 400 kilometers on the trip odometer. I don't think I burned the entire 40 liters, it was below the empty mark when I got to a gas station, and 30 liters of gas brought it up to full again. So I figure I burned about 30-32 liters of fuel, does that sound about right? If anyone here is good with math, can they convert all that to miles per gallon for me? I'm curious to see how much fuel the Aspire is burning. One quick question, how far will the gas gauge go below the E mark?
Help me calculate my Aspire's MPG
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Friends don't help friends do metric conversions.
It was easier when the dollar was strong....you could just say everything in Canada was about 62 % of the USA. (well only applies to distance and money)
Another hint, 1 gallon of water = 8.33 lbs/gallon.
1 liter of pure water = 1 kg (1cc=1gram)
Have fun!
It was easier when the dollar was strong....you could just say everything in Canada was about 62 % of the USA. (well only applies to distance and money)
Another hint, 1 gallon of water = 8.33 lbs/gallon.
1 liter of pure water = 1 kg (1cc=1gram)
Have fun!
Bob & Doug McKenzie taught me metric converions a long time ago. Double it and add 30, ah.
30 liters = 7.93 gallons
400KM = 248.55 miles
248.55/7.93 = 31.34 MPG
400/30 = 13.33 KPL
I rented an auto version of this car in 1995. I think it got about 25-27 MPG. It was down in Florida...I was concerned that it wouldn't make it across the state w/o a fuel up, becauseof the small fuel tank.
30 liters = 7.93 gallons
400KM = 248.55 miles
248.55/7.93 = 31.34 MPG
400/30 = 13.33 KPL
I rented an auto version of this car in 1995. I think it got about 25-27 MPG. It was down in Florida...I was concerned that it wouldn't make it across the state w/o a fuel up, becauseof the small fuel tank.
Otherwise identical cars can vary a lot. There is only one way to find out for sure.
31 is pretty good! Gas prices jumped up another 6 cents per liter around here, so a liter of regular now costs $1.129. I sure picked the right time to buy a small car..
"So I figure I burned about 30-32 liters of fuel, does that sound about right?"
yes, that would be approximately correct. I usually fill the tank until the pump shuts off, it gives me a more constant "full" point.
****************
"One quick question, how far will the gas gauge go below the E mark? "
It will go until the car runs out of gas....
seriously, it depends on the car AND it's not accurate at low levels anyway.
You should always calculate based on how much fuel you add since the last time you filled the tank. The guage is only an estimate.
so.....
400km x.6214= 248 ~=250 miles
32 liters x .2642 ~=8.5 gallons
therefore 250 miles / 8.5g ~=29 miles per gallon
not bad but nothing to get excited about. For a car that size I would expect better.
yes, that would be approximately correct. I usually fill the tank until the pump shuts off, it gives me a more constant "full" point.
****************
"One quick question, how far will the gas gauge go below the E mark? "
It will go until the car runs out of gas....
seriously, it depends on the car AND it's not accurate at low levels anyway.
You should always calculate based on how much fuel you add since the last time you filled the tank. The guage is only an estimate.
so.....
400km x.6214= 248 ~=250 miles
32 liters x .2642 ~=8.5 gallons
therefore 250 miles / 8.5g ~=29 miles per gallon
not bad but nothing to get excited about. For a car that size I would expect better.
You need to watch the Saab episode of Seinfeld, to know how low the gauge will go.
Once it is empty, you know the lowest point.
Once it is empty, you know the lowest point.
Some info on "running on empty":
Below is a very long re-post of some information about fuel levels by Jim Hopkins. Mr. Hopkins is retired after a very long and distinguished career as a trainer and troubleshooter for Toyota of North America (I think this is correct - apologies to Mr. Hopkins if I omitted something.) What follows is a long read but may clear up some issues discussed in this thread. =======
Warning: The "low fuel" warning light was NOT put on your car so that you could avoid the embarrassment of having to be rescued by the AAA because your engine quit from fuel starvation (many people somehow think it was put there just for that very purpose). Avoid using it for this purpose. It was never intended to encourage driver neglect. It is not there to release drivers from their responsibilities and encourage bad driving habits. It is there because it was "mandated" by "corporate lawyers" to meet emission control regulations in the early 1980s. That's why it's there!
The law required that all car manufacturers, warranty all emission controls for 5 years to assure compliance with emission control regulations.
Now! The engineers were fully convinced that all the right components ( platinum spark plugs, EGR, fuel injection etc., etc.) would easily meet and surpass all the legal specifications, and warranty requirements for emission controls, with only "TWO" major conditions: #1 absolutely NO leaded fuel (poisons the catalytic converter), and #2 only very limited amounts of raw unburned) fuel should ever be permitted to reach the catalytic converter (overheats the converter).
The unleaded fuel problem was eventually resolved by the installation of a smaller diameter fuel filler inlet into the fuel tank filler neck, and appropriate "unleaded fuel only" customer warning stickers, were strategically placed, With the cooperation
of the fuel suppliers, providing smaller gas pump filler nozzles ONLY for unleaded fuel, consumer mistakes were hopefully minimized.
However, the raw fuel problem was much more difficult to resolve since "fuel starvation" (misfire) causes unburned fuel to enter the catalytic converter.
If there ever is "NO" fuel available at the fuel pump pickup inlet inside the fuel tank, the fuel pump simply cannot pump any fuel! That's just elementary! With a loss of fuel delivery, the fuel rail "residual" pressure is quickly depleted, especially if the engine's demands for fuel are high, This fuel pressure drop causes a drastic reduction in the amount of fuel delivered by the injectors by each fuel pulse. The fuel mixture then becomes very "lean" (the same amount of intake air, combined with less fuel). "Lean" fuel mixtures burn much "hotter" than rich fuel mixtures, and must therefore be avoided, especially at high engine loads, and high engine RPM (more power pulses per minute) to prevent overheating the combustion chamber, and burning the valves, etc. (also exhaust emissions can increase). Lean burning is the first stage of fuel starvation.
If the mixture becomes even "leaner" ignition suddenly becomes impossible, and "lean combustion" instantly becomes "lean misfire". If a fuel charge fails to ignite the unburned gasoline and air mixture then passes right through the engine combustion chamber completely unburned. This mixture rapidly cools the overheated combustion chamber, and continues right on through the exhaust manifold, and reaches the catalytic converter, where the mixture is then burned, likely causing the converter to overheat in it’s attempts to prevent tailpipe emissions.
Now! The if fuel pump constantly delivers several times as much fuel as the engine could possibly ever use to generate it's maximum rated horsepower, fuel starvation under high loads is virtually impossible. Only if someone has somehow outrageously tricked up the engine with larger fuel injectors, overridden the computers RPM limiter, force fed the engine (turbo-super charger), etc. etc. etc.
doubling the engine's rated horsepower, or restricted the fuel pressure line or fuel filter, installed an ultra strong drive line and tires with colossal tire grip, etc. etc., could they ever create an engine load that even approach the limits of the fuel pump
delivery capacity to supply. So, forget larger fuel pumps promising increased horsepower. I have seen mechanics quickly drain a fuel tank just by opening a fuel line and directing it into a storage tank , and then running the fuel pump (a neat trick). I will explain how to do this later on in this post. Only a drag racer
could ever consume fuel that rapidly. Don't buy a larger fuel pump to increase performance.
Since fuel starvation will ALWAYS occur when the fuel in the fuel tank becomes DEPLEATED. The design engineer is very limited in what he can do to prevent this "driver" initiated problem. A larger fuel tank will only delay the problem, as eventually all cars will run out of fuel (even solar powered cars, when the sun doesn't shine). This ultimately always becomes a driver education problem, and not really an engineering design problem. Driver education is however very, very difficult!
Fuel starvation occurs long, long before the fuel in the tank is ever actually exhausted. The fuel pump pick up cannot be located at the very bottom of the fuel tank, as it would then suck in water and sediment, etc. So, the fuel sloshes merrily around (in spite of baffles) up the sides of the fuel tank every time the vehicle is
affected by any inertia forces, leaving the fuel pump pickup pipe high and dry. Way before you ever actually "run out of fuel" your engine can suffer real fuel starvation, misfire. etc., and dump a lot of your costly fuel right down the exhaust manifold and into the catalytic converter to be converted into wasted heat (so that at least it won't pollute the environment).
An engine turning even 2000 RPM fires 1000 times in a minute, so the driver will probably never even notice 50 misfires (5%) per minute. But the driver looses 5% of the engine's horsepower, and wastes 5% of his fuel. Note: Low fuel levels in the fuel tank will "NOT" cause lean misfire at idle (when the car is stationary / no inertia forces), where engine misfire is usually easily detected. Also fuel starvation will not show up at emission control test stations because they test on a rolling road (no inertia forces) Always keep the TOP half of your fuel tank full!
If you don't believe me, just try holding an open cup of coffee (even a quarter full) while the driver weaves around through busy traffic, over potholes, rounds curves etc. (without spilling any coffee). Imagine what is happening inside the car's fuel tank, as the fuel pump pick up pipe gasps for fuel. Fuel also runs to the rear of the fuel tank when ascending hills, further aggravating fuel starvation. A lot of poor fuel economy is caused by fuel starvation. as well, as contributing to catalytic converter overheating. Always keep the TOP half of your fuel tank full!
Inertia forces from rough roads can be reduced by: smoothing the road surface (municipal problem), softening the suspension (an engineering compromise), reducing vehicle speed (driver education). These inertia forces are very difficult to predict. When driving on rough "back country" roads always keep the TOP half of your fuel tank full!
Braking can generate very large inertia forces, but when the throttle closes (very likely under hard braking), fuel injection is completely terminated by the engine computer until the engine RPM slows down to near idle speed. Then at idle, so little fuel is injected that any air entrained in the rapidly circulating fuel stream is quickly released back into the fuel tank with very little consequence. So braking inertia (although very high) is not really a fuel starvation factor.
Cornering forces can be very high and can easily cause fuel starvation (just ask NASCAR drivers). Acceleration forces are particularly nasty for fuel starvation. Acceleration forces are limited by both engine torque and tire adhesion (two wheels) , and are therefore much lower than braking forces (four wheels). Acceleration forces are usually of much shorter duration than cornering forces because they cannot be sustained, but since, acceleration forces correspond directly with a very high fuel demand by the engine, they are therefore very, very likely to cause fuel starvation and lean misfire. When both acceleration and cornering forces are combined on a rough road, chances of fuel starvation greatly increase. For aggressive driving, always keep the TOP half of your fuel tank full!
If you have installed stiffer shock absorbers, stickier tires, increased your engine's power, or drive more briskly than normal, you are very likely to experience even more fuel starvation and lean engine misfire from inertia displacement of fuel inside the fuel tank. "Savvy" street racers often challenge a competitor if they
spot a low fuel gauge reading in his car. With a full fuel tank, they likely have an advantage. Always keep the TOP half of your fuel tank full!
The design engineers ESTIMATE the fuel level at which "THEY" anticipate fuel starvation "MAY" become problematic and lead to catalytic converter overheating. They consider the vehicles intended use (family sedan, sports car, etc.), engine horsepower, tire adhesion , etc. Based on this (original equipment) prediction, they appropriately locate a fuel level sensor inside the fuel tank to monitor the "low fuel" warning level. This "low fuel sensor is located very near the fuel pump pickup as this is the point requiring monitoring.
A float gauge (as is the fuel gauge) would not work, since it would be all over the place as the fuel sloshed around in the tank, and would need very heavy damping (like a normal fuel level gauge), which would make it very slow to respond and too inaccurate.
Instead a tiny electrical resistor, encapsulated in a plastic cover is used as a "low fuel level" warning sensor. This resistor is continually (ignition on) fed a very small voltage, which causes the resistor to heat up, as the resistor heats, it's resistance increases, when it's resistance increases it's current flow decreases because the applied voltage is kept constant. Therefore it's current flow reflects it's temperature.
As long as this sensor remains submerged underneath the fuel inside the fuel tank, it's heat is continuously absorbed by the surrounding fuel, so it cannot heat up and it's current draw will remain relatively high.
Should the fuel level drop, exposing the sensor to the air inside the fuel tank, the resistor will soon heat up, causing it's resistance to increase, less current will now flow, and the computer will interpret the low current flow as an indication of a low fuel level in the fuel tank, and respond by turning on the "low fuel" warning light. This light will never come on at start up, even if the fuel level is low, because it requires several seconds for the sensor to warm up sufficiently to signal the computer to turn on the warning light. This process will take a little longer on a very cold morning.
While rounding a very long curve at high speed you may have noticed the light come on after a few seconds delay as the fuel is drained away from the sensor by inertia allowing it to heat up, and turn on the warning light, to warn the driver of impending fuel starvation (do you always heed this warning?). As the car then resumed a straighter, stable course the sloshing fuel returned to a more tranquil state, quenched the sensors heat and extinguished the warning light. Did you then forget about the warning? This process will occur much more rapidly if the fuel in the tank has been previously heated by engine heat absorbed from the engine fuel rail.
Most people assume that the owner's manual says "Warning! You can only drive about 50 km more before you run out of fuel" It DOESN'T!" Check your owner's manual. What is printed there???
It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on. Car manufacturers assume no legal liability whatever for any damage to the vehicle's engine or emission control components etc. caused by owners who do not heed this warning light. It is considered, driver neglect! Read your owner's manual "very"
carefully, and always keep the TOP half of your fuel tank full!
Catalytic converters are engine garbage disposals. Don't risk turning your costly fuel into garbage, and tossing it away into the catalytic converter for disposal! Always keep the TOP have of your fuel tank full!
I have actually fielded owner complaints that their "low fuel" warning light was incorrectly calibrated at the factory, because (they assured me) there was still lots of fuel remaining in the fuel tank after the light came on. They complained that they found the warning light very annoying, and distracting while they proceeded to consume all of the fuel remaining inside the fuel tank. Have you ever felt this way about your low fuel warning light? Better change!
Not only are you at great risk of inducing fuel starvation, but the fuel remaining inside the fuel tank is also at greater risk of being overheated and vaporizing etc. Also, there is much greater air space inside a fuel tank with a low fuel level for water vapors to condense, causing water to collect in the bottom of the tank to freeze in fuel lines, etc. Add a half cup of methyl hydrate once or twice a year, and keep the TOP half of your fuel tank full!
If you must continue to drive with the "low fuel" warning light on, drive at reduced speeds, avoid sudden maneuvers etc. and fuel up "just as soon" as you possibly can. If you are an exuberant driver fill up much, much sooner. In hot weather, on long fast drives, fill up much sooner. If you have modified your car to achieve more cornering "Gs" fill up much, much sooner. If you experience any loss of power during hard acceleration, fill up "immediately". If the "low fuel warning light ever comes on
during hard acceleration, your fuel is probably both too hot, and too low, so forget any racing till you fill up your fuel tank.
Many a Sunday drag racer has been defeated by much lesser cars because the fuel in his fuel tank simply flowed away from the fuel pump pick up under hard acceleration, or taking a fast corner. Many street racers experience fuel starvation and are then sold "humongous", expensive fuel pumps as an "upgrade". They then fill up their fuel tanks, and will swear that it was their trick fuel pump installation etc. that delivered a terrific performance improvement. That is, until the next time they race with a low fuel level.
Few racers like to admit that their tricked out car, lost out simply because they neglected to fill up the fuel tank, and they just ran out of gas under hard acceleration. A new key ring would probably have done as much for their performance as a the " humongous" fuel pump! The cheapest performance "upgrade you can ever make to your car is to keep the TOP half of your fuel tank full!
If you really must race with low fuel levels, change your fuel tank over to one engineered specifically for racing. It may not sound as sexy as many other highly advertised performance products as a racing fuel tank cannot promise more power, but it is the best cure for fuel starvation. Do not install racing fuel tanks with a much smaller fuel capacity, unless you install an appropriate fuel heat exchanger on the fuel pressure regulator return line to the fuel tank. Make sure your replacement fuel tank installation is safe and has the appropriate openings for fuel vapor collection, etc.
I am sure many people reading this are wondering why on earth, I have devoted so much time detailing what seemingly appears to them to be the obvious. However, when I am asked by people for a good tip on maintaining their cars I often reply: "Keep the TOP half of your fuel tank full!". They usually look amazed and just snicker, and reply: "Oh I know all about that, I once ran out of gas about 3 years ago, but lately I have been very lucky. A few close calls. But I haven't run right out of fuel!" for along. "Now! Tell me something exotic, and exciting, like: How to get more power and acceleration, better handling, better gas mileage, how to make it start faster in hot weather, what additives to use to clean my fuel injectors, etc., etc."
Then I tell them that I have just told them how to do this, but they just didn't understand why I said it, and obviously, a much more in depth and detailed explanation is required for them to fully appreciate the full significance of this advice. This advice is very well known, but very few people will ever give you this detailed an explanation, probably because it serves no commercial market, and may even adversely impact on their future sales. Yet, I think it is necessary information, in order for a drivers to FULLY appreciate the full consequences of their neglect. How many times do drivers breathe a sigh of relief as they reach a service station just in time, and then congratulate themselves for getting away with it. Truth is, they probably really didn't get away with it! They just think they did! Actually they probably unwittingly cheated themselves out of some "free "gasoline.
I can also, positively guarantee that if you always keep the "TOP" half of your fuel tank full, you will NEVER, ever "run out of gas". I can also guarantee that it will cost you much less money to keep the TOP half of your fuel tank full than the bottom half. You have my word on it! If you have any friends that you think would benefit from this information, please pass it along. I always hate to see people senselessly dumping their good fuel down their catalytic converters.
I’ll bet when you refueled on a hot day, the fuel cap went "whoosh" releasing the high pressure built up by the hot vaporizing fuel during your long drive, both by the sun’s heat and that carried away from the engine by the rapidly circulating fuel combined. Now, at a constant fuel temperature a slight vacuum would always be left behind as the fuel vacates the tank. That "whoosh" however, is a good sign that the fuel storage system is well sealed and that fuel vapors inside the tank, are being effectively controlled, but it is also a sign of very "HOT" fuel inside the fuel tank. Note: The evaporative emission control (EVAP) will allow quite a high , but limited amount of pressure to develop inside the fuel tank before fuel vapors are allowed to escape out into the charcoal canister, this residual fuel tank pressure reduces the formation of even more fuel vapors under hot fuel conditions.
Should a vacuum develop as the fuel cools or as fuel is used up, with no temperature increase, the "fuel tank cap" has a little valve in it to let atmospheric air into the fuel tank, so that the tank is not crushed by atmospheric pressure. This valve also requires a little vacuum to open it, so it is not unusual to sometimes find a slight vacuum inside the fuel tank, if fuel temperatures are fairly stable. This slight vacuum "hiss" is also the sign of a good fuel tank cap when refueling.
Remember to always tighten the fuel filler cap till it "clicks" to assure a positive fuel filler cap seal. If you never hear a "whoosh" or "hiss" replace the fuel filler cap, or cap gasket, immediately, because, you are wasting the fuel you have paid for and are just polluting the atmosphere with it.
Below is a very long re-post of some information about fuel levels by Jim Hopkins. Mr. Hopkins is retired after a very long and distinguished career as a trainer and troubleshooter for Toyota of North America (I think this is correct - apologies to Mr. Hopkins if I omitted something.) What follows is a long read but may clear up some issues discussed in this thread. =======
Warning: The "low fuel" warning light was NOT put on your car so that you could avoid the embarrassment of having to be rescued by the AAA because your engine quit from fuel starvation (many people somehow think it was put there just for that very purpose). Avoid using it for this purpose. It was never intended to encourage driver neglect. It is not there to release drivers from their responsibilities and encourage bad driving habits. It is there because it was "mandated" by "corporate lawyers" to meet emission control regulations in the early 1980s. That's why it's there!
The law required that all car manufacturers, warranty all emission controls for 5 years to assure compliance with emission control regulations.
Now! The engineers were fully convinced that all the right components ( platinum spark plugs, EGR, fuel injection etc., etc.) would easily meet and surpass all the legal specifications, and warranty requirements for emission controls, with only "TWO" major conditions: #1 absolutely NO leaded fuel (poisons the catalytic converter), and #2 only very limited amounts of raw unburned) fuel should ever be permitted to reach the catalytic converter (overheats the converter).
The unleaded fuel problem was eventually resolved by the installation of a smaller diameter fuel filler inlet into the fuel tank filler neck, and appropriate "unleaded fuel only" customer warning stickers, were strategically placed, With the cooperation
of the fuel suppliers, providing smaller gas pump filler nozzles ONLY for unleaded fuel, consumer mistakes were hopefully minimized.
However, the raw fuel problem was much more difficult to resolve since "fuel starvation" (misfire) causes unburned fuel to enter the catalytic converter.
If there ever is "NO" fuel available at the fuel pump pickup inlet inside the fuel tank, the fuel pump simply cannot pump any fuel! That's just elementary! With a loss of fuel delivery, the fuel rail "residual" pressure is quickly depleted, especially if the engine's demands for fuel are high, This fuel pressure drop causes a drastic reduction in the amount of fuel delivered by the injectors by each fuel pulse. The fuel mixture then becomes very "lean" (the same amount of intake air, combined with less fuel). "Lean" fuel mixtures burn much "hotter" than rich fuel mixtures, and must therefore be avoided, especially at high engine loads, and high engine RPM (more power pulses per minute) to prevent overheating the combustion chamber, and burning the valves, etc. (also exhaust emissions can increase). Lean burning is the first stage of fuel starvation.
If the mixture becomes even "leaner" ignition suddenly becomes impossible, and "lean combustion" instantly becomes "lean misfire". If a fuel charge fails to ignite the unburned gasoline and air mixture then passes right through the engine combustion chamber completely unburned. This mixture rapidly cools the overheated combustion chamber, and continues right on through the exhaust manifold, and reaches the catalytic converter, where the mixture is then burned, likely causing the converter to overheat in it’s attempts to prevent tailpipe emissions.
Now! The if fuel pump constantly delivers several times as much fuel as the engine could possibly ever use to generate it's maximum rated horsepower, fuel starvation under high loads is virtually impossible. Only if someone has somehow outrageously tricked up the engine with larger fuel injectors, overridden the computers RPM limiter, force fed the engine (turbo-super charger), etc. etc. etc.
doubling the engine's rated horsepower, or restricted the fuel pressure line or fuel filter, installed an ultra strong drive line and tires with colossal tire grip, etc. etc., could they ever create an engine load that even approach the limits of the fuel pump
delivery capacity to supply. So, forget larger fuel pumps promising increased horsepower. I have seen mechanics quickly drain a fuel tank just by opening a fuel line and directing it into a storage tank , and then running the fuel pump (a neat trick). I will explain how to do this later on in this post. Only a drag racer
could ever consume fuel that rapidly. Don't buy a larger fuel pump to increase performance.
Since fuel starvation will ALWAYS occur when the fuel in the fuel tank becomes DEPLEATED. The design engineer is very limited in what he can do to prevent this "driver" initiated problem. A larger fuel tank will only delay the problem, as eventually all cars will run out of fuel (even solar powered cars, when the sun doesn't shine). This ultimately always becomes a driver education problem, and not really an engineering design problem. Driver education is however very, very difficult!
Fuel starvation occurs long, long before the fuel in the tank is ever actually exhausted. The fuel pump pick up cannot be located at the very bottom of the fuel tank, as it would then suck in water and sediment, etc. So, the fuel sloshes merrily around (in spite of baffles) up the sides of the fuel tank every time the vehicle is
affected by any inertia forces, leaving the fuel pump pickup pipe high and dry. Way before you ever actually "run out of fuel" your engine can suffer real fuel starvation, misfire. etc., and dump a lot of your costly fuel right down the exhaust manifold and into the catalytic converter to be converted into wasted heat (so that at least it won't pollute the environment).
An engine turning even 2000 RPM fires 1000 times in a minute, so the driver will probably never even notice 50 misfires (5%) per minute. But the driver looses 5% of the engine's horsepower, and wastes 5% of his fuel. Note: Low fuel levels in the fuel tank will "NOT" cause lean misfire at idle (when the car is stationary / no inertia forces), where engine misfire is usually easily detected. Also fuel starvation will not show up at emission control test stations because they test on a rolling road (no inertia forces) Always keep the TOP half of your fuel tank full!
If you don't believe me, just try holding an open cup of coffee (even a quarter full) while the driver weaves around through busy traffic, over potholes, rounds curves etc. (without spilling any coffee). Imagine what is happening inside the car's fuel tank, as the fuel pump pick up pipe gasps for fuel. Fuel also runs to the rear of the fuel tank when ascending hills, further aggravating fuel starvation. A lot of poor fuel economy is caused by fuel starvation. as well, as contributing to catalytic converter overheating. Always keep the TOP half of your fuel tank full!
Inertia forces from rough roads can be reduced by: smoothing the road surface (municipal problem), softening the suspension (an engineering compromise), reducing vehicle speed (driver education). These inertia forces are very difficult to predict. When driving on rough "back country" roads always keep the TOP half of your fuel tank full!
Braking can generate very large inertia forces, but when the throttle closes (very likely under hard braking), fuel injection is completely terminated by the engine computer until the engine RPM slows down to near idle speed. Then at idle, so little fuel is injected that any air entrained in the rapidly circulating fuel stream is quickly released back into the fuel tank with very little consequence. So braking inertia (although very high) is not really a fuel starvation factor.
Cornering forces can be very high and can easily cause fuel starvation (just ask NASCAR drivers). Acceleration forces are particularly nasty for fuel starvation. Acceleration forces are limited by both engine torque and tire adhesion (two wheels) , and are therefore much lower than braking forces (four wheels). Acceleration forces are usually of much shorter duration than cornering forces because they cannot be sustained, but since, acceleration forces correspond directly with a very high fuel demand by the engine, they are therefore very, very likely to cause fuel starvation and lean misfire. When both acceleration and cornering forces are combined on a rough road, chances of fuel starvation greatly increase. For aggressive driving, always keep the TOP half of your fuel tank full!
If you have installed stiffer shock absorbers, stickier tires, increased your engine's power, or drive more briskly than normal, you are very likely to experience even more fuel starvation and lean engine misfire from inertia displacement of fuel inside the fuel tank. "Savvy" street racers often challenge a competitor if they
spot a low fuel gauge reading in his car. With a full fuel tank, they likely have an advantage. Always keep the TOP half of your fuel tank full!
The design engineers ESTIMATE the fuel level at which "THEY" anticipate fuel starvation "MAY" become problematic and lead to catalytic converter overheating. They consider the vehicles intended use (family sedan, sports car, etc.), engine horsepower, tire adhesion , etc. Based on this (original equipment) prediction, they appropriately locate a fuel level sensor inside the fuel tank to monitor the "low fuel" warning level. This "low fuel sensor is located very near the fuel pump pickup as this is the point requiring monitoring.
A float gauge (as is the fuel gauge) would not work, since it would be all over the place as the fuel sloshed around in the tank, and would need very heavy damping (like a normal fuel level gauge), which would make it very slow to respond and too inaccurate.
Instead a tiny electrical resistor, encapsulated in a plastic cover is used as a "low fuel level" warning sensor. This resistor is continually (ignition on) fed a very small voltage, which causes the resistor to heat up, as the resistor heats, it's resistance increases, when it's resistance increases it's current flow decreases because the applied voltage is kept constant. Therefore it's current flow reflects it's temperature.
As long as this sensor remains submerged underneath the fuel inside the fuel tank, it's heat is continuously absorbed by the surrounding fuel, so it cannot heat up and it's current draw will remain relatively high.
Should the fuel level drop, exposing the sensor to the air inside the fuel tank, the resistor will soon heat up, causing it's resistance to increase, less current will now flow, and the computer will interpret the low current flow as an indication of a low fuel level in the fuel tank, and respond by turning on the "low fuel" warning light. This light will never come on at start up, even if the fuel level is low, because it requires several seconds for the sensor to warm up sufficiently to signal the computer to turn on the warning light. This process will take a little longer on a very cold morning.
While rounding a very long curve at high speed you may have noticed the light come on after a few seconds delay as the fuel is drained away from the sensor by inertia allowing it to heat up, and turn on the warning light, to warn the driver of impending fuel starvation (do you always heed this warning?). As the car then resumed a straighter, stable course the sloshing fuel returned to a more tranquil state, quenched the sensors heat and extinguished the warning light. Did you then forget about the warning? This process will occur much more rapidly if the fuel in the tank has been previously heated by engine heat absorbed from the engine fuel rail.
Most people assume that the owner's manual says "Warning! You can only drive about 50 km more before you run out of fuel" It DOESN'T!" Check your owner's manual. What is printed there???
It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on. Car manufacturers assume no legal liability whatever for any damage to the vehicle's engine or emission control components etc. caused by owners who do not heed this warning light. It is considered, driver neglect! Read your owner's manual "very"
carefully, and always keep the TOP half of your fuel tank full!
Catalytic converters are engine garbage disposals. Don't risk turning your costly fuel into garbage, and tossing it away into the catalytic converter for disposal! Always keep the TOP have of your fuel tank full!
I have actually fielded owner complaints that their "low fuel" warning light was incorrectly calibrated at the factory, because (they assured me) there was still lots of fuel remaining in the fuel tank after the light came on. They complained that they found the warning light very annoying, and distracting while they proceeded to consume all of the fuel remaining inside the fuel tank. Have you ever felt this way about your low fuel warning light? Better change!
Not only are you at great risk of inducing fuel starvation, but the fuel remaining inside the fuel tank is also at greater risk of being overheated and vaporizing etc. Also, there is much greater air space inside a fuel tank with a low fuel level for water vapors to condense, causing water to collect in the bottom of the tank to freeze in fuel lines, etc. Add a half cup of methyl hydrate once or twice a year, and keep the TOP half of your fuel tank full!
If you must continue to drive with the "low fuel" warning light on, drive at reduced speeds, avoid sudden maneuvers etc. and fuel up "just as soon" as you possibly can. If you are an exuberant driver fill up much, much sooner. In hot weather, on long fast drives, fill up much sooner. If you have modified your car to achieve more cornering "Gs" fill up much, much sooner. If you experience any loss of power during hard acceleration, fill up "immediately". If the "low fuel warning light ever comes on
during hard acceleration, your fuel is probably both too hot, and too low, so forget any racing till you fill up your fuel tank.
Many a Sunday drag racer has been defeated by much lesser cars because the fuel in his fuel tank simply flowed away from the fuel pump pick up under hard acceleration, or taking a fast corner. Many street racers experience fuel starvation and are then sold "humongous", expensive fuel pumps as an "upgrade". They then fill up their fuel tanks, and will swear that it was their trick fuel pump installation etc. that delivered a terrific performance improvement. That is, until the next time they race with a low fuel level.
Few racers like to admit that their tricked out car, lost out simply because they neglected to fill up the fuel tank, and they just ran out of gas under hard acceleration. A new key ring would probably have done as much for their performance as a the " humongous" fuel pump! The cheapest performance "upgrade you can ever make to your car is to keep the TOP half of your fuel tank full!
If you really must race with low fuel levels, change your fuel tank over to one engineered specifically for racing. It may not sound as sexy as many other highly advertised performance products as a racing fuel tank cannot promise more power, but it is the best cure for fuel starvation. Do not install racing fuel tanks with a much smaller fuel capacity, unless you install an appropriate fuel heat exchanger on the fuel pressure regulator return line to the fuel tank. Make sure your replacement fuel tank installation is safe and has the appropriate openings for fuel vapor collection, etc.
I am sure many people reading this are wondering why on earth, I have devoted so much time detailing what seemingly appears to them to be the obvious. However, when I am asked by people for a good tip on maintaining their cars I often reply: "Keep the TOP half of your fuel tank full!". They usually look amazed and just snicker, and reply: "Oh I know all about that, I once ran out of gas about 3 years ago, but lately I have been very lucky. A few close calls. But I haven't run right out of fuel!" for along. "Now! Tell me something exotic, and exciting, like: How to get more power and acceleration, better handling, better gas mileage, how to make it start faster in hot weather, what additives to use to clean my fuel injectors, etc., etc."
Then I tell them that I have just told them how to do this, but they just didn't understand why I said it, and obviously, a much more in depth and detailed explanation is required for them to fully appreciate the full significance of this advice. This advice is very well known, but very few people will ever give you this detailed an explanation, probably because it serves no commercial market, and may even adversely impact on their future sales. Yet, I think it is necessary information, in order for a drivers to FULLY appreciate the full consequences of their neglect. How many times do drivers breathe a sigh of relief as they reach a service station just in time, and then congratulate themselves for getting away with it. Truth is, they probably really didn't get away with it! They just think they did! Actually they probably unwittingly cheated themselves out of some "free "gasoline.
I can also, positively guarantee that if you always keep the "TOP" half of your fuel tank full, you will NEVER, ever "run out of gas". I can also guarantee that it will cost you much less money to keep the TOP half of your fuel tank full than the bottom half. You have my word on it! If you have any friends that you think would benefit from this information, please pass it along. I always hate to see people senselessly dumping their good fuel down their catalytic converters.
I’ll bet when you refueled on a hot day, the fuel cap went "whoosh" releasing the high pressure built up by the hot vaporizing fuel during your long drive, both by the sun’s heat and that carried away from the engine by the rapidly circulating fuel combined. Now, at a constant fuel temperature a slight vacuum would always be left behind as the fuel vacates the tank. That "whoosh" however, is a good sign that the fuel storage system is well sealed and that fuel vapors inside the tank, are being effectively controlled, but it is also a sign of very "HOT" fuel inside the fuel tank. Note: The evaporative emission control (EVAP) will allow quite a high , but limited amount of pressure to develop inside the fuel tank before fuel vapors are allowed to escape out into the charcoal canister, this residual fuel tank pressure reduces the formation of even more fuel vapors under hot fuel conditions.
Should a vacuum develop as the fuel cools or as fuel is used up, with no temperature increase, the "fuel tank cap" has a little valve in it to let atmospheric air into the fuel tank, so that the tank is not crushed by atmospheric pressure. This valve also requires a little vacuum to open it, so it is not unusual to sometimes find a slight vacuum inside the fuel tank, if fuel temperatures are fairly stable. This slight vacuum "hiss" is also the sign of a good fuel tank cap when refueling.
Remember to always tighten the fuel filler cap till it "clicks" to assure a positive fuel filler cap seal. If you never hear a "whoosh" or "hiss" replace the fuel filler cap, or cap gasket, immediately, because, you are wasting the fuel you have paid for and are just polluting the atmosphere with it.
So in a nutshell, when the little red light comes on get some more gas, for, uhm, whatever reason....
actually I've heard this many times before, but always from the same person.
Has anyone ever met this fellow?
Has Toyota ever verified his existance?
Has this same info ever come from a separate and independent source?
I can't argue with any of his statements but that hardly qualifies it as my endorsement. Like it would mean much anyway.
curiosity:
Most euro contries (via the EU in particular) disallow the use of a red light/LED/etc as an indicator unless there is physical danger to the operator or other persons. I'm not sure fuel starvation qualifies. Running out of fuel in freezing temps might.
actually I've heard this many times before, but always from the same person.
Has anyone ever met this fellow?
Has Toyota ever verified his existance?
Has this same info ever come from a separate and independent source?
I can't argue with any of his statements but that hardly qualifies it as my endorsement. Like it would mean much anyway.
curiosity:
Most euro contries (via the EU in particular) disallow the use of a red light/LED/etc as an indicator unless there is physical danger to the operator or other persons. I'm not sure fuel starvation qualifies. Running out of fuel in freezing temps might.
holy crap
"Most people assume that the owner's manual says "Warning! You can only drive about 50 km more before you run out of fuel" It DOESN'T!" Check your owner's manual. What is printed there???
It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on. Car manufacturers assume no legal liability whatever for any damage to the vehicle's engine or emission control components etc. caused by owners who do not heed this warning light. It is considered, driver neglect! Read your owner's manual "very"
carefully, and always keep the TOP half of your fuel tank full!"
Actually, most car owners manuals say it's safe to drive with the low fuel light on, just fill up at the next gas station you come across. I've driven 60 miles or more in my 88 Celica with the low fuel light on and I could have gone further too.
It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on. Car manufacturers assume no legal liability whatever for any damage to the vehicle's engine or emission control components etc. caused by owners who do not heed this warning light. It is considered, driver neglect! Read your owner's manual "very"
carefully, and always keep the TOP half of your fuel tank full!"
Actually, most car owners manuals say it's safe to drive with the low fuel light on, just fill up at the next gas station you come across. I've driven 60 miles or more in my 88 Celica with the low fuel light on and I could have gone further too.
31 MPG is not that great for an Aspire.
another curiosity:
the low fuel light is NOT covered by ANY part of the Toyota emissions warranties. All other emissions related parts are covered by a separate (or several separate) emissions-related conmponent warranties as mandated by Federal law.
2 dealers here can't find the light or the tank sensor on any emissions related warranty lists.
If it is required to meet emissions, why isn't it covered?
the low fuel light is NOT covered by ANY part of the Toyota emissions warranties. All other emissions related parts are covered by a separate (or several separate) emissions-related conmponent warranties as mandated by Federal law.
2 dealers here can't find the light or the tank sensor on any emissions related warranty lists.
If it is required to meet emissions, why isn't it covered?
EPA rated the 94 automatic Aspire as getting 34 MPG, highway. We all know how accurate those numbers are..
They should ask Ford how they managed to get a low fuel light to work on the 1988 Ford Mustang using a float gauge (the same one as for the fuel gauge) as the input.
And why, if it's required, are there many vehicles made since the early 80s without a low fuel light?
and just to throw another log on the fire, the owner's manual of my 97 camry makes no mention of performance or warranty or emmisions in reference to the light.
It says ..."It is a good idea to keep the tank over 1/4 full."
"If the fuel level approaches "E" or the fuel level warning light comes on, fill the fuel tank as soon as possible.
If the fuel tank is completely empty, the malfunction indicator lamp comes on. Fill the fuel tank immediately."
(note the malfunction indicator is a separate issue and not the Low Fuel Warning light. even here it just mentions it being reset by the dealer or "by driving several times" certainly casting further doubt on the "not driving" part. I will assume I can drive it to the dealer to have it reset....)
The Toyota shop manual makes no mention of this being emissions related. It gives a simple test procedure and none the diagnostics indicate this sensor as a source fault. The only time it appears to be called for inspection is if the light doesn't come on or if it fails to go off after filling the tank or "driving around"! No diagnostic codes indicate "inspect or r/r sending unit."
As far how it works, it works just like he says. It is not a mechanical float switch.
But as to: "It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on." "
I find this nowhere in ANY of my Toyota manuals (97 camry, 93 camry, 02 Highlander.)
This may be one of those very legit writings that at one point in time was 100% accurate and factual. However, as in much netlore, it has been "enhanced" by well-meaning persons to the point of introducing factual errors and editors' opinions so much that the entire writing is now somewhat in doubt.
Mr Hopkins, if he ever existed, may be amazed at the life his writing has spawned.
Sorry for taking us so far OT, and forgive my crusading but I do deal with this type of thing daily.
It may be time to send this one to Urban Legends.....
It says ..."It is a good idea to keep the tank over 1/4 full."
"If the fuel level approaches "E" or the fuel level warning light comes on, fill the fuel tank as soon as possible.
If the fuel tank is completely empty, the malfunction indicator lamp comes on. Fill the fuel tank immediately."
(note the malfunction indicator is a separate issue and not the Low Fuel Warning light. even here it just mentions it being reset by the dealer or "by driving several times" certainly casting further doubt on the "not driving" part. I will assume I can drive it to the dealer to have it reset....)
The Toyota shop manual makes no mention of this being emissions related. It gives a simple test procedure and none the diagnostics indicate this sensor as a source fault. The only time it appears to be called for inspection is if the light doesn't come on or if it fails to go off after filling the tank or "driving around"! No diagnostic codes indicate "inspect or r/r sending unit."
As far how it works, it works just like he says. It is not a mechanical float switch.
But as to: "It reads "Warning! "DO NOT DRIVE" when the "low fuel" warning light is on." "
I find this nowhere in ANY of my Toyota manuals (97 camry, 93 camry, 02 Highlander.)
This may be one of those very legit writings that at one point in time was 100% accurate and factual. However, as in much netlore, it has been "enhanced" by well-meaning persons to the point of introducing factual errors and editors' opinions so much that the entire writing is now somewhat in doubt.
Mr Hopkins, if he ever existed, may be amazed at the life his writing has spawned.
Sorry for taking us so far OT, and forgive my crusading but I do deal with this type of thing daily.
It may be time to send this one to Urban Legends.....
low fuel warning light???? never have had a car with one! sure glad I learned how to read a fuel gauge!!
That could be an indication that the guy who wrote this actually did work for Toyota (and wasn't aware of how other automakers approached and solved the problem).
Actually, EPA says:
MT = 36/42
AT = 29/34
I think he is doing just fine, at 31, given the age and condition.
Like i said, I rented an AT version of these for a month in 1995. Best it got was 27, with hurricane tail wind out in the flats in the swamp. 22/25 was more the order. I remember this vividly because I was surprised of the poor mileage the 1.3 returned.
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