Fuel Gauge Readings
#1
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I have found the following more detailed information in the TCH Repair Manual concerning the fuel remaining in the tank at certain nominal readings of the fuel gauge. Remember that the tank's nominal capacity is 65 L (~17.2 galUS).
Page ME-36:
F(ull) reading corresponds nominally to 62.9 L (~16.6 galUS) in the tank.
Half-full reading corresponds nominally to 35 L (~9.2 galUS) in the tank.
E(mpty) reading corresponds nominally to 7.0 L (~1.8 galUS) in the tank.
Page ME-52:
The fuel light comes on when there is nominally 9.8 L (~2.6 galUS) left in the tank.
From this information, I calculate that each minor division on the fuel gauge (there are 16 of them) corresponds to 3.5 L (~0.9 galUS). Moreover, the half-way mark corresponds nominally to precisely half the difference between F and E. [Since the range from Full to Empty is (F - E) = 62.9 - 7 = 56 L (~14.8 galUS), it follows that the Half-way point should be at 28 L above E, i.e. at 7 + 28 = 35 L, which is indeed what Toyota claims.] My experience is that the fuel gauge does indeed read approximately linearly over this range.
According to Toyota's numbers, this also means that there is ~2.1 L (~0.6 galUS) of "overfill" between the F(ull) mark and the nominal tank capacity of 65 L. At the bottom end, it states that, when reading E(mpty), there's nominally still 7.0 L (~1.8 galUS) left in the tank.
Remember that these are only nominal values, so don't rely absolutely on them! But they do give useful ballpark numbers.
Stan
Page ME-36:
F(ull) reading corresponds nominally to 62.9 L (~16.6 galUS) in the tank.
Half-full reading corresponds nominally to 35 L (~9.2 galUS) in the tank.
E(mpty) reading corresponds nominally to 7.0 L (~1.8 galUS) in the tank.
Page ME-52:
The fuel light comes on when there is nominally 9.8 L (~2.6 galUS) left in the tank.
From this information, I calculate that each minor division on the fuel gauge (there are 16 of them) corresponds to 3.5 L (~0.9 galUS). Moreover, the half-way mark corresponds nominally to precisely half the difference between F and E. [Since the range from Full to Empty is (F - E) = 62.9 - 7 = 56 L (~14.8 galUS), it follows that the Half-way point should be at 28 L above E, i.e. at 7 + 28 = 35 L, which is indeed what Toyota claims.] My experience is that the fuel gauge does indeed read approximately linearly over this range.
According to Toyota's numbers, this also means that there is ~2.1 L (~0.6 galUS) of "overfill" between the F(ull) mark and the nominal tank capacity of 65 L. At the bottom end, it states that, when reading E(mpty), there's nominally still 7.0 L (~1.8 galUS) left in the tank.
Remember that these are only nominal values, so don't rely absolutely on them! But they do give useful ballpark numbers.
Stan
#2
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Interesting info, thanks. I've always been curious about the coolant systems in the car (ie the ICE coolant system vs the hybrid coolant system). Things like which one has more capacity, whether the hybrid system has any kind of thermostat (do electric motors run better at a regulated temp, does it care if it's cold unlike the ICE?), what components are actually temperature controlled, etc. Any interesting info about that in the repair manual?
#3
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Stan, intresting info, thanks!
I am starting to see a trend on my TCH, when I get the low fuel lght, i try very hard to not fill it yet, as I always seem to get to the 0 miles to empty, then only put in 14.1-14.4 gallons US...Yesterday, I decided I would stretch it a little bit...i was reading 8 miles to empty, then in less than 1 mile, it went to 0 left, and never came back up. Also, the guage started showing below E. I am aware of sloshing and such, but it became very nerveracking to drive like that, and I filled up taking only 14.5 gallons. Same station and pump as I usualy use. The computer reported 40.6MPG, and calculated was 40.5MPG I had gone 587 miles...not too shabby I would say.
I am starting to see a trend on my TCH, when I get the low fuel lght, i try very hard to not fill it yet, as I always seem to get to the 0 miles to empty, then only put in 14.1-14.4 gallons US...Yesterday, I decided I would stretch it a little bit...i was reading 8 miles to empty, then in less than 1 mile, it went to 0 left, and never came back up. Also, the guage started showing below E. I am aware of sloshing and such, but it became very nerveracking to drive like that, and I filled up taking only 14.5 gallons. Same station and pump as I usualy use. The computer reported 40.6MPG, and calculated was 40.5MPG I had gone 587 miles...not too shabby I would say.
#4
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I have found the following more detailed information in the TCH Repair Manual concerning the fuel remaining in the tank at certain nominal readings of the fuel gauge. Remember that the tank's nominal capacity is 65 L (~17.2 galUS).
Page ME-36:
F(ull) reading corresponds nominally to 62.9 L (~16.6 galUS) in the tank.
Half-full reading corresponds nominally to 35 L (~9.2 galUS) in the tank.
E(mpty) reading corresponds nominally to 7.0 L (~1.8 galUS) in the tank.
Page ME-52:
The fuel light comes on when there is nominally 9.8 L (~2.6 galUS) left in the tank.
Page ME-36:
F(ull) reading corresponds nominally to 62.9 L (~16.6 galUS) in the tank.
Half-full reading corresponds nominally to 35 L (~9.2 galUS) in the tank.
E(mpty) reading corresponds nominally to 7.0 L (~1.8 galUS) in the tank.
Page ME-52:
The fuel light comes on when there is nominally 9.8 L (~2.6 galUS) left in the tank.
I have gone as far as 100 miles before the line dropped down to the full mark. When I fill up I don't overfill.
I calculate that I have 2.6 gallons left when I hit empty. I have verified it by filling up at this point, and the tank only took 14.5 gallons.
My light comes on when I have 4.2 gallons left in the tank.
#5
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Good info Stan. As they say your mileage may vary. I just filled up yesterday after stretching out the tank a bit. I went 714 miles, driving 88 miles past E, and only put 16.4 gallons in the tank. That is a bit lower than I really care to take it. Now I'm not so sure if there was a half gallon left or not.
I believe on Edmunds a TCH owner posted about filling up after running out and putting in surpising large quantity of fuel - I think it was 17.5 or so gallons.
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I believe on Edmunds a TCH owner posted about filling up after running out and putting in surpising large quantity of fuel - I think it was 17.5 or so gallons.
#7
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The car really holds a lot of fuel. I can't wait until summer to go for a 700 mile tank!
#8
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Droid13 — Yes, there are indeed other interesting pieces of information in the TCH Repair Manual. The MGs and converter/inverter have a separate temperature monitor and their own water cooling system with a thermostatically controlled electric pump. The attached pages ME-36 to 38 from the Meter section indicates some of the parameters that are being monitored by the various ECUs, and will give you some idea.
Stan
Stan
#9
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More information on the TCH ICE:
Here are two more interesting sections from the "Hybrid Vehicle" section of the TCH Repair Manual. Pages HV-42to49 lists the ICE sensor data that can be accessed (by Toyota's Intelligent Tester) on the CAN bus. Pages HV-75to76 is interesting in that it lists the "history" data that the car keeps track of!
Stan
Here are two more interesting sections from the "Hybrid Vehicle" section of the TCH Repair Manual. Pages HV-42to49 lists the ICE sensor data that can be accessed (by Toyota's Intelligent Tester) on the CAN bus. Pages HV-75to76 is interesting in that it lists the "history" data that the car keeps track of!
Stan
Last edited by SPL; 02-14-2007 at 12:58 PM. Reason: Corrected name of "Intelligent Tester."
#10
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Thanks Stan, the history info is really cool. Talk about "Big Brother". This thing keeps track of all your goof ups. Those of you that like to be a little too aggressive using the shifter or have clumsy pedal feet, you are being WATCHED!
The elapsed run time is interesting, only counts up to a bit over 18 hours. I wonder if you strapped on some NASA diapers and actually managed to drive longer than this would the car have a Y2K type computer issue if it has to roll back to 0.
The elapsed run time is interesting, only counts up to a bit over 18 hours. I wonder if you strapped on some NASA diapers and actually managed to drive longer than this would the car have a Y2K type computer issue if it has to roll back to 0.