Heavy fuel usage/high revs

[Keith Mitchell]

Hello, have a 2014 YRS, 1.5 auto, just curious as according to different websites I should be averaging between 6 and 6.5 l/100kms. The car has a ?42 litre tank so if it was achieving this I would assume approx 700km/tank. This car is lucky to get 350..
some things I have noticed, at highway speeds (110km/hr) the engine is raving at approximately 3000rpm. This seems very high. I also have a 2012 Camry and at the same speed it revs at 2200.. is this little Yaris not going into top gear?
When travelling at 80km/h (sometimes even slower speeds) on a downhill and I use the brakes the transmission will drop a gear for no reason.
I’m suspecting transmission issues or a manifold leak of some type? Any help from others experiencing the same issues..

[WeeYari]

3000 rpm at 110kph is right on par. Keep in mind that the bigger the engine displacement, the lower it will rev. The Camry with the larger engine will naturally rev lower. At highway speeds, a V8 will be sub 2000rpm.
When it comes to efficiency, 6 to 6.5 l/100km can realistically only be achieved under optimal driving conditions. For the average Joe, this would be cruising on open highway at a steady 80 kph. No stops, starts or changes in acceleration.

[kevinj93]

It's normal for the transmission to downshift when you brake.
If you use cruise control, it will also downshift to slow down as you go downhill. At the same time, the ECU will stop injecting fuel, so the current consumption display will drop to zero.

My son drives my Yaris to work 4 days a week in a 20 km round trip. Average fuel consumption now displays 7.3 litres per hundred kilometres.

[Keith Mitchell]

3000 rpm at 110kph is right on par. Keep in mind that the bigger the engine displacement, the lower it will rev. The Camry with the larger engine will naturally rev lower. At highway speeds, a V8 will be sub 2000rpm.
When it comes to efficiency, 6 to 6.5 l/100km can realistically only be achieved under optimal driving conditions. For the average Joe, this would be cruising on open highway at a steady 80 kph. No stops, starts or changes in acceleration.

Whilst I get that a smaller engine is going to rev higher, the Camry has a 2.5l engine and weighs 2200kg and the Yaris has a 1.5l engine and weighs less than half the Camry weight. Also the Camry avge fuel consumption is 8.5 and the Camry is running very close to that and I don’t drive them differently

[slick1]

We have a 1.3 L 2015 Yaris and a 2006 1.3 L Yaris (both have a 2NZ-FE engine) and get just under 600 km out of a 42 L tank i.e. ~14 km/L (7.1 L/100 km) average... although they can get as low as ~12 km/L and as high as ~17 km/L depending on how they are driven. We have 200,000 km of fuel data on the 2015 and 370,000 km on the 2006.

350 km (8.3 km/L) out of a tank is very low... although the 1.5 L should logically use slightly more than a 1.3 L engine.

The auto on our Yaris also sometimes drops a gear. There seems to be a certain speed that triggers this gear change. If you avoid that particular speed/load it doesn't seem to do it.

You definitely have a problem with fuel use.

How many km has the car travelled?
Is this a noisy engine or a quiet one?
What do the spark plugs look like?
What is the compression like?
Have you considered doing an oil analysis: It's a good way of identifying many problems.
Is the car using oil?

What does a mechanic suggest?

:-)