What is the normal fuel consumption for carburetor type Toyota 3A engine?
My 1986 Toyota Carina AT 150 gets 11 km/l in city and 14 km/l on highways.
How can I increase could I increase the fuel economy?

I did tune up recently, (replaced spark plugs, adjusted the carburetor, and replaced all the plug wires).

  • 1
    Don't you mean decreasing fuel consumption - as in consuming LESS fuel?
    – Andrew P.
    Aug 27, 2014 at 10:45
  • 2
    How much money do you want to spend? Aug 27, 2014 at 11:30
  • Purchase a recent model vehicle and fuel economy will triple or at least double. A 30 year old vehicle has paid its dues.
    – Old_Fossil
    Jun 16, 2016 at 5:33

3 Answers 3


You might expect about 19.6 km/l (all things perfect, maximum efficiency), but 14.5 km/l highway to 11.5 km/l (city) is realistic if fuel/ignition/engine are in excellent condition and the tires are correctly inflated; those numbers are original factory spec.

There are physical limits to the efficiency one might expect from any given car due to weight, wind resistance, unavoidable rolling resistance, inertia, and mechanical losses.

  • according to your conclusion, it is good enough.
    – tenna
    Aug 28, 2014 at 6:07
  • @tenna - Yep, it looks like you probably shouldn't expect much more efficiency than you're getting now. Do check the tire pressure, make sure it's to spec, but unless you lighten the car or add air dams, you're pretty much finished. Aug 28, 2014 at 13:08
  • can i install EFI kit for my car to improve fuel economy? is it worth with comparing its cost?
    – tenna
    Aug 30, 2014 at 8:40
  • @tenna, EFI may buy you a slight boost, but not much. Aug 30, 2014 at 12:21

If you just rebuilt the engine, something you probably haven't taken into account is frictional losses while the engine is breaking in. Engines take about a 1000 miles to break in (unless you do some specific break-in procedures). Once the engine is broke-in, you can expect better mileage from the engine. Things are a little tighter right after rebuild than they will be later on. Once the break-in process is done, things loosen up, oil flows a little easier, rings slide up and down the cylinder easier, gears and belts roll a little easier ... all of this equates to better gas mileage. How much better is the real question here, but it will improve some.

  • i wish to replace oil filter, engine oil and air filter in 1000 to 1500 km. is it OK? is there any other important things to consider?
    – tenna
    Aug 28, 2014 at 6:11
  • When doing engine break-in, usually you'll run the engine up with the startup oil for about 20 minutes of run time. Then change out the oil and oil filter. Then run your engine for the next 1000 miles (1600 km) and change it again. Then continue on with whatever oil change interval you are going to run from that point forward. No real need to change the air filter, as it's only doing it's job, so normal intervals from the start is a good choice. Aug 28, 2014 at 21:00

This may go without saying, but changing your driving style may help very much here. I used to have an older car with a V6 and I'd get roughly 16 MPGs (Car was supposed to get 21 city, 25 hwy). I recently got a newer car that had almost identical fuel economy (22/26) but it had an LED indicator to show if my driving style was consuming more/less fuel. I'm actually getting close to 25 MPG average just from changing my driving style. I know it isn't just from newer tech since when I first got the car, I was at about 19-20 MPGs (the engine was broken in so the econ readings were accurate for the most part, I'm sure.)

Things that help most are:

  • Coasting to a stop
  • Accelerating and trying to keep engine RPMs around 2k or lower if possible
  • Maintaining a steady speed once you're at your speed limit (i.e. cruise control)
  • sure! maintain RPM & speed and avoid sudden acceleration/retardation is good point.but it cant exceed mentioned fuel consumption at the present. (11 km/l in city and 14 km/l on highways) anyway thanks!
    – tenna
    Aug 30, 2014 at 8:30

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