Using DFCO to increase your MPG - Toyota Yaris Forums

jjonrofl · 01-01-2010, 04:21 PM

Brian- then what is the noise the engine/transmission/something makes when I begin to brake at about 45mph down a hill? And the car stays at about 40mph?

supmet · 01-01-2010, 04:25 PM

Quote:

Originally Posted by jjonrofl

Brian- then what is the noise the engine/transmission/something makes when I begin to brake at about 45mph down a hill? And the car stays at about 40mph?

DFCO doesn't make a noise, it just sounds like the engine revving from a downshift.

I'm not sure what the buzzing you are talking about is.

Yaris Hilton · 01-01-2010, 05:56 PM

DFCO doesn't make a noise, and it doesn't rev the engine or downshift an automatic transmission. There's just a sudden slight deceleration as the idle fuel is cut off. You have to be paying close attention to feel it.

There is a separate function in the ECU that downshifts the transmission if you're coasting downhill and apply the brakes. It increases the "engine braking" so you don't have to use the brakes as much. Touch the gas pedal and let it off, and it'll upshift to high gear and let you pick up speed coasting.

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01-01-2010, 04:21 PM	#1
jjonrofl Drives: 2009 Yaris LB Join Date: Dec 2009 Location: Maryland, USA Posts: 37	Brian- then what is the noise the engine/transmission/something makes when I begin to brake at about 45mph down a hill? And the car stays at about 40mph?

01-01-2010, 05:56 PM	#3
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	DFCO doesn't make a noise, and it doesn't rev the engine or downshift an automatic transmission. There's just a sudden slight deceleration as the idle fuel is cut off. You have to be paying close attention to feel it. There is a separate function in the ECU that downshifts the transmission if you're coasting downhill and apply the brakes. It increases the "engine braking" so you don't have to use the brakes as much. Touch the gas pedal and let it off, and it'll upshift to high gear and let you pick up speed coasting.