Exactly!

 

To Fray Adjacent -- thanks very much for posting this. It's a big help.

I've been trying to wrap my admittedly non-technical brain around coasting in neutral in my MT Fit versus coasting in gear. Let's see if I have it right. To maximize my mpg, I should coast in neutral in situations where I can see far ahead and where I don't intend to ultimately stop -- such as cresting a sizable hill on the interstate and starting down the downhill side. But when I'm coming off the interstate onto an exit, I should coast in gear -- fifth, then maybe a quick shift down to fourth if it's a long exit ramp. Likewise, when I'm rolling down a hill that leads to a stop sign on a highway, I should keep the transmission in one of the higher gears and my foot completely off the gas pedal, since I know I'm going to be stopping at the intersection.

Anybody -- am I reading this correctly?

 

Quoted because that's exactly right, and the more different ways people say it the better. Well done!

 

I've been pleasantly surprised how far the AT will coast in gear. It's more than one would normally expect. Even with DFCO, I still use the brake a lot. During my commute, coasting would do no good as there aren't any long enough coasting stretches to make it worthwhile.

Anyone have any info regarding AT damaging from going in/out of gear at speed?

 

If the fuel injectors cut off completely, does that mean you get better mileage by doing pulse and glide (with the glide period being used for in-gear coasting) than by maintaining a steady speed?

 

According to the guy who got 70mpg, yes.

 

Unless I have made an error in light timing, I always press my FAS switch and coast in. No question of less fuel. Brakes are relatively cheap. I bump start if the traffic moves before I get to a stop.

 

I am with Paul on this one! FAS switch FTMFW!

Paul, I heading your way Friday, DISNEY WORLD FTW!

 

Have fun Shawn. Weather is Perfect

 

Is it FRIDAY YET???

 

if you're coast and gliding, wouldn't you want to turn the engine off and coast in neutral, so that you aren't engine braking? it seems counter-productive to pulse and engine brake, even if you are not consuming fuel while doing it.

 

That's exactly what neutral/clutch down is supposed to do--take up as little fuel as possible to keep the engine from stalling.

Of course--your gear is physically connected to the engine, therefore more resistance than when you're in neutral.

As a previous poster noted, use either one when appropriate. Coming off most freeway ramps, I leave it in gear and I still have to brake at the end. Coasting to a red light at residential speeds, I put it in neutral for the distance.

 

Isn't this information kind of obvious? I don't know of any fuel injection vehicle that does NOT cut fuel when engine braking.

A basic guide to follow is to start slowing/braking early (obvious) and downshift to maximize coasting/engine off period.

And your accessories such as power steering or power brakes will not stop functioning because they are belt driven... powered by your motor spinning.

However, if shutting down the motor or using the FAS switch (which I assume is shutting down the motor) during coasting, your powered accessories will no longer be powered.

 

Just so's ya know... I've spent years turning wrenches, some of that time for a living, and it was only recently that I found out about DFCO, so NO, the information is not 'obvious'.

Power steering on the Fit is electric. Engine on or off, you still have steering assist. 'Power' brakes are vacuum assisted. They still work well for some time after shutting the engine off. More than enough to come to a complete stop from 80mph, were it necessary. Even aftger the vacuum assist 'runs out' as it were, you still can brake the car.

 

I been turnin wrenches for a number of years too, and I thought it was common knowledge that fuel injected vehicles do this. I'm not quite old enough to have privelidge of working on carburated vehicles, so I don't know how they behave. Maybe you've been working with those types alot, eh, ya old dinosaur?

This I did not know. Thanks for the info.

However last time my power brakes were off in the fit, I had to practically stand on the brakes to get it to stop from 30mph. And I'm not a light guy (fattie).

 

Can anyone enlighten me on how to use DFCO effectively with my AT fit?

Should I be using the paddle shifters? When should I put the car in neutral vs. leaving it in gear? I tend to turn the engine off at stop lights that I know will be long but when decelerating to a stop, I was wondering if I should use the paddle shifters to get into another gear or just coast in "D"?

 

I helped my uncle rebuld a small block chevy when I was 6... Dear Lord... 35 years ago. Fortunately, most of the cars I've personally owned have been FI instead of carbuerated, but I do have some knowledge of how carbs work. Most of the carbed engines I've worked on have been 'small', as in single cylinder air cooled. I've played with everything from 32cc 2-strokes to a 1800CI air-cooled, twin-turbo V12.

Odd. I've had no problems when braking with the engine off. Try shutting off on a long clear stretch and see just how hard it is to stop. I rode the brakes down a long hill for almost a mile before I ran out of assist.

 

Hey, hey, my Yaris forum gets a shout out. I've increase my mpg anywhere from 5-10 mpg by using a few of those techniques, mainly DFCO.

 

So I finally got my scangauge II in my 2009 GE8 AT. I was watching it today as I was coasting down hill but I never saw GPH go below .22. Is this how it's supposed to work with automatic trans? Or maybe I need to tweek something on the SG?

 

When you use DFCO with an AT, it works longer if you use the paddles to downshift when the engine reaches 1300 RPM or so (Sport mode FTW). You can keep doing that till you reach 2nd gear. I do not recommend downshifting into 1st when moving, except in situations when you need to take off FAST.

Also, if the engine is turning at only ~1100 RPM to begin with, it might not go into DFCO at all unless you downshift.

Using A/C or defrost will make it harder to go into DFCO as well. If you are in 5th gear and using A/C or defrost, you will usually need to downshift to 3rd to get DFCO.