Ignition vs. Roll start?

[sbergman27]

Just drive normally. The Yaris is smart enough to cut the fuel completely when:

1. The accelerator pedal is at idle position.
2. The transmission is in gear.
3. The clutch is engaged.
4. Engine speed is above 1100 rpm. (I think it's 1100 anyway.)
5. Engine is at normal operating temperature.

Your fuel consumption will be zero under those conditions. Not even the normal 0.2 GPH for idling will be used. Search for "DFCO", or "Deceleration Fuel Cut Off".

-Steve

[1stToyota]

Originally Posted by Alypuppy

I must say I am impressed that with the Yaris mileage obtaining 40mpg over 1368 miles with a good mix of long freeway driving through New York and Massachusetts on winter fuel and tires. I cannot wait for summer!

However, I have a question. There are a lot of hills in my area and I often find places to cost for over a quarter of a mile. For these I turn of the car and let it roll and am even able to roll into and park my car in the school parking lot after .2 miles of costing and over 360 degrees of turning.

Most of my coasting, though, is when I see a red light in the distance. Sometimes the light turns green and I love the extra mpg boost from not having to start from a full stop, but I would like to know:

--> Which is better? Roll start the car in an appropriate gear? Or use the ignition system to start the car? Also, many say the wear and tear of ignition is similar to 7 seconds of the engine being on, so I turn my car off for nearly every light and am debating about turning off the car to roll up to stop signs... is there too much of a good thing? I do use the fuel shutoff DFCO (sp) as well, but I find I would rather just turn the car off and coast for greater distances.

Also, did I notice that the ODO only counts when the car is actually in the on position? After driving an SUV, the lack of power steering in the Yaris feels like the power steering in my Xterra, and it seems the break hydraulics only repressurize when the engine is on. I cannot afford a Scangauge, but do I have to turn the car back to the on position without igniting the engine to have a more accurate mileage calculation? Plus, it gets a little cranky and likes to turn the engine back on if it has not spun down fully and it is a bit distracting to have to turn the car on and off several times to finally but the engine to sleep.
Is this true for the other hypermilers? It's funny, sometimes I feel like my car is off more than it is on!


Thank you
Alypuppy

09 HB Manual Trans.

Originally Posted by sbergman27

Just drive normally. The Yaris is smart enough to cut the fuel completely when:

1. The accelerator pedal is at idle position.
2. The transmission is in gear.
3. The clutch is engaged.
4. Engine speed is above 1100 rpm. (I think it's 1100 anyway.)
5. Engine is at normal operating temperature.

Your fuel consumption will be zero under those conditions. Not even the normal 0.2 GPH for idling will be used. Search for "DFCO", or "Deceleration Fuel Cut Off".

-Steve

+1

Yes, just drive normally, and let the car do its job...no need for the added distraction

[BailOut]

Originally Posted by 1stToyota

+1

Yes, just drive normally, and let the car do its job...no need for the added distraction

I wholeheartedly disagree. The car only knows how to do its job one way, and that's the way the engineers thought it out. Their way is by far not the only way.

And cycling the ignition is not a "distraction". Your eyes don't leave the road, you still have assisted steering, and the brakes are good for 4-5 touches. Seriously, of all the things that one can gripe on for being a distraction while driving, cycling the ignition is at the bottom of my list.

There is a time and place for DFCO usage but it has two severe limitations:

1) It steals momentum.
2) The engine uses fuel again once any of its conditions are no longer met.

Coasting with the engine off is much more efficient in all aspects when you know you'll be coming to a stop for a while, or when you want to maintain more momentum in between the times you let the engine run.