MPG info display

[georgec]

I just purchased a 2005 Camry XLE. Great car!!!

I'm sort of a geek. I really like the information display (MPG, elapsed time, average speed). On my first two fuel fill-ups, I checked the accuracy of the average MPG; is it way off. For example, on a trip, the info showed 39.2 average MPG, but the actual fuel and miles driven gave a calculation of 33.1. Also, the estimated remaining driving distance (before a fill-up is needed) is very inaccurate.

Does anybody know whether the info display can be calibrated or adjusted to be more accurate?

Thanks

georgec

[SmokingTires]

Maybe your calculations are off?


Otherwise, take it to the dealer ship and have them check it. They can probably fix it for you. And I bet it is covered under your warrenty too

[terrastrife]

ya know you do have quite a big bit of fuel tank after the Empty mark

[anuthaCamry]

wait till you put some miles on it first, and break in the engine a lil. when you fill up reset the avg mpg, avg mph, and driving time. instantaneous mpg and range can't be reset. The avg mpg and avg mph are easily confused so maybe it was 39 avg mph.

also consider the fact that the computer will maybe need to calibrate itself over time too.

I've personally observed 33 mpG at 64-65 mph,

[georgec]

Thanks. Yes, I did reset all the info, including avg mph and remaining distance. But after each reset and fill-up, the average MPG at the next fill-up did not match the actual miles driven divided by the gallons required for the fill-up.

I don't think the engine break-in would affect this; I was comparing the actual miles and actual gallons. True, the mpg will increase with time. But even with a brand new engine, I would think the computer should be more accurate than 20%.

No, it wasn't avg mph; that was approximately 60 mpg, because I was on a trip with freeway driving most of the way.

Have you read somewhere that the computer needs to calibrate itself over time?

geo

Originally Posted by anuthaCamry

wait till you put some miles on it first, and break in the engine a lil. when you fill up reset the avg mpg, avg mph, and driving time. instantaneous mpg and range can't be reset. The avg mpg and avg mph are easily confused so maybe it was 39 avg mph.

also consider the fact that the computer will maybe need to calibrate itself over time too.

I've personally observed 33 mpG at 64-65 mph,

[georgec]

Yes, Of course. But even with a quite a bit of fuel left, if I use the actual miles driven since the last fill-up, divided by the actual gallons used since the last fill-up, the result is the actual mpg the car achieved. If I had also reset the computer at the last fill-up, the computer calculation should match what I measure. That is regardless of how much fuel is left when I gas up. But the computer showed 39.2, and my actual calculation showed 33. So the computer is off by about 20%.

;

Originally Posted by terrastrife

ya know you do have quite a big bit of fuel tank after the Empty mark

[04sev6camry]

Originally Posted by terrastrife

ya know you do have quite a big bit of fuel tank after the Empty mark

a little off topic but how many gallons do u have left after u hit E? also, how many gallons do u have when the fuel light comes on cause the light comes on a bit before E?
by the way, i have an 04 SE V6 (GEN 5), but i know its probably the same for all GEN5s.

[georgec]

I haven't actually hit E yet. I've typically filled up with about 4 gallons remaining (18.5 gallon tank). Also, the low fuel light has not come on yet. My understanding from other '05 Camry owners is that about 3 gallons are left when the light comes on. That should give between 70 and 100 miles more driving before the tank is actually empty.

geo

Originally Posted by 04sev6camry

a little off topic but how many gallons do u have left after u hit E? also, how many gallons do u have when the fuel light comes on cause the light comes on a bit before E?
by the way, i have an 04 SE V6 (GEN 5), but i know its probably the same for all GEN5s.

[04sev6camry]

i do about the same thing but ill have the fuel light come on and drive around a little while and still only put about 14-16 gal in it, thats about the longest ill run it, normaly i fill up about 1/4 tank

[anuthaCamry]

I think that this is normal, I'm guestimating that you have only 450-750 miles on your car and that the computer needs to calibrate itself before it will be accurate. If this doesn't correct itself after 2000 miles or so I would bring it back to the simians at the dealership.

[moeharri]

Georgec, is your trip computer getting any better? I just bought a 2005 XLE as well, and in the first two fillups, it said I was getting 34 each time according to the computer (I reset it after each fillup), but I actually only got 22 (lots of warming up due to cold) and 28 mpg. So that means my first fillup was off by 12mpg and the 2nd was off by 6mpg, which I do consider to be WAY off.

[anuthaCamry]

They won't be accurate until 600-800 miles.

[amerikim]

Maybe it does it's calculations only when actually driven, doesnt factor in warmups or idle in neutral? If you do want to test your milage, make sure you are carrying a couple of gallons of gas with you. Don not forget that a gas tank does have an amount on unusable gas.

[2k4CamThrilla]

yeah it depends how much you put in the tank, i already experimented.

[georgec]

Moe;

No, it hasn't gotten better. My opinion is that it should not change, either better or worse, with engine break-in. The actual MPG might change, yes. But the display should "accurately" measure what the car is actually doing. I took it into my dealer, who is very accommodating and cares a lot about customer issues. But they are dumbfounded, meaning that they don't know how to adjust or which component(s) might be at fault. They kept the car for a day and confirmend my results. Then they called Toyota directely and talked to an "expert". He told them that I should drive for 8000 miles (yes, eight thousand!) then see whether the problem improves. Hogwash, as my daddy once said! That makes no sense. If there's a logical reason for that, explain it to me, and I'll understand. Or just tell me that the display design is just not very accurate. I'd be satisfied (not pleased, but satisfied) with that. But to tell me that 8000 miles will improve it makes no sense. I told the dealer that in polite but definte terms. They said they's call the Toyota technician again and get back with me. That was about a week ago, and I haven't heard anything else.

I did discover that the consumed gas is "measured" indirectly, not with an actual flowmeter. The design senses manifold vacuum and other parameters and indirectly determines the fuel usage. Then, using the elapsed miles since last reset, makes the calculation. So I can understand that the measurement might be an approximation. But to have a 25% or 50% error such as you and I are getting means that the display is useless. Right now, I'm not using it. Very disappointing to me, since that was one of several factors that led me to purchase the Toyota versus a Honda EX.

By the way, the estimated remaining miles display is, I imagine, also calculated using indirect indicators. So the fact that the info is inacurate as well as AVERAGE MPG is not much of a surprise. As an example, my display will show that I have 50 miles left on the tank of gas, but the low fuel light has not come on. And if I fill up at that point, I actually have four gallons left. That's enough to go a hundred miles. So that info is off significantly also and therefore of no use.

Let's keep corresponding. If you get any more information or a fix from your dealer, let me know. I could then show that to my dealer. I'll do the same for you, of course.

Regards,

geo

Originally Posted by moeharri

Georgec, is your trip computer getting any better? I just bought a 2005 XLE as well, and in the first two fillups, it said I was getting 34 each time according to the computer (I reset it after each fillup), but I actually only got 22 (lots of warming up due to cold) and 28 mpg. So that means my first fillup was off by 12mpg and the 2nd was off by 6mpg, which I do consider to be WAY off.