The brochure says 20 gal (US gal I assume since who else uses gal for anything)
The Owner's Manual on page 498 says 21 US gal and 17.5 Imperial gal/ Canada - once upon a time.
Twice I have had an exact fuel gauge reading of 13.5 US gal to fill from a 1/4 tank reading. This of course implies a 4/3 x 13.5 -> 18.0 gal fuel tank!
Is this a matter of inflation or what?
My mileage is consistent 26 mil/gal at 70 mph on HWY. but only about 14.3 mil/gal city and very short 1-4 mile trips to stores etc. but no idling in traffic congestion.
There are Imperial gallons, used by Imperialists? ;-)
If the brochure is from Toyota Motor Sales, U.S.A., then it is probably safe to assume that they mean U.S. gallons and it is also probably safe to assume that in the event of a difference between the owner's manual and the brochure, the owner's manual is more likely to be correct because the folks who produce the brochures are not technical people.
The fuel gauge is not an accurate indicator of measurement of fuel in the tank, and movement of the fuel gauge is not linear. The fuel sender is basically a float on an arm, much like the float that controls water entering your toilet tank, and the float moves in an arc. The fuel tank is generally not symmetrical and has an odd shape, so although the float will indicate the level in the tank, it does not necessarily indicate volume of fuel in the tank.
I'm not sure if you have a question or not, but if you are questioning why there is such a large discrepancy between city and highway mileage, it is because an engine is least fuel-efficient and puts out the highest emissions during the first few miles after a cold start. When the engine is first started cold, additional fuel is needed to keep it running smoothly, so idle speed is higher. When the engine is first started, the O2 sensors have not warmed up enough to work, so the computer uses a "default" value to determine how much fuel to deliver, rather than how much is actually needed. Also, when the engine is first started, the transmission holds lower gears a little longer and does not shift into overdrive until the engine has begun to warm up. Holding the transmission in lower gears helps the engine warm up faster so emissions are reduced, at the cost of fuel economy.
If you want to improve your city mileage, save up all your short trips and combine them into longer trips if possible. For example, after the engine has warmed up, you can probably travel 5 miles in the amount of fuel consumed during the first 2 miles of travel after a cold start.
Your decent highway fuel economy indicates that everything seems to be running efficiently.
This vehicle has given me more satisfaction than anything I purchased in regent memory. Good attention to details and great ride on the hwy. The actual amount of fuel that can be sucked out of the tank (and used) does make a difference on the Left Side with our great distances between many pumps or towns - say late at night. I know one should not run far below 1/4 tank. T seems indifferent to what numbers are used by them. Perhaps there was a real simple answer.
As for city fuel economy - some people are fans of letting the car warm up for say 5 min before they get in it and drive anywhere. Is this anything other than false economy and superstition?
I was surprised to see just how great the difference was in mileage between short and long trips in a modern car.
Do you happen to have the trip computer with its "Estimated Distance to Empty" ? My wife's 2005 sienna does, and it seems to be pretty accurate as long as the type of driving is similar. (In other words, driving 300 miles highway and then doing a bunch of errands in town will fool the computer and could get you into trouble.)
My wife is the main driver of the sienna so she knows best on range and fuel capacity, but we frequently take 350+ mile highway trips with no worry about running empty. The tank does seem to be right about the 20 gallon size in our 2004. I know it is more than 19g. :) If I had to guess, I'd have guessed 20 or 21 gallons.
I don't know if T changed the tank since 2004, or if T uses different tanks with different packages. Mine is a pretty basic 8 seater.
Your mistake is that you assume 1/4 tank on the guage is an accurate reading. THE ONLY JOB of the fuel guage is to let you know how long you have before you have to lace up your sneakers and start walking. The guage is RELATIVE information, not acutal.
If you get 20 mpg, and can carry 40 gallons, then you have a 400 mile range. That is the only really important thing you need to know. This tidbit can be helpful if you've gone 326 miles, and the sign reads NEXT SERVICE 75 MILES.
Starting a car and letting it warm up for 5 minutes or even 1 minute before getting in and driving anywhere is a waste of fuel. If you want to improve fuel economy, get in the car, fasten your seat belt, adjust the mirrors, and do whatever else your routine includes before starting the engine. When you start the engine, wait for the engine RPM to stabilize, usually less than 5 seconds, put the transmission in gear, and start driving.
The big difference is due to the many short trips, where the engine barely warms up and the transmission does not shift into overdrive. The transmission is probably geared for good acceleration around town and lower RPM on the highway. 2 things that will make a significant improvement in fuel economy are combining the short trips so that the engine is warmed up for more of the driving, and allowing the transmission to upshift by accelerating a little more slowly and lifting your foot off the throttle just before you get to your cruising speed. The transmission will shift to a higher gear a little sooner, and doing that routinely will make a difference. My Lexus has a 4 liter V8, my commute is 10 miles of suburban driving, and I get 19 ~ 20 MPG around town, about 25 MPG on the highway. I check MPG on every tank so I know if there is a dropoff in performance and I need to check things out. If we trade cars and my wife or one of my kids drive it for just 1 day, the fuel economy on that tank will drop to 17 ~ 18 MPG. My advice is to be cognizant of what gear the transmission is in and let it shift to high gear as soon as you can.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.