Hi all...I got my '13 sport A/T a week back and I went on a trip to upstate new york yesterday to get feel of the car on freeways and to see some mpg numbers. Total round trip was around 430 miles and gas used was 11 gallons. I actually did lot of coasting during my drive to achieve that many miles. So I just wanted check if coasting is ok to do mechanically? During one stretch I was coasting at 65 mph and accidentally put car in reverse for a second hopefully that didn't do any damage to engine. Also, does new cars nowadays require break in time or my drive was too early? Car has 678 miles on it now. Appreciate your responses....

 

dealer told me break in is 600, but dont race it till 1k :P

 

If you're talking about putting it in neutral when coasting, you don't have to press the button on the knob to shift to neutral, just move it up. That way, you won't risk going to Reverse. There's a lock between Neutral and Reverse but no lock between Neutral, Drive and Sport.
You can shift up and down Neutral, Drive and Sport without pressing the shifter button. That's how I do it anyways.

 

Leaving your car in gear, and removing your foot from the gas shuts the injectors off above idle rpm.

Shifting into neutral lets engine speed return to idle where it has to use fuel to keep its self spinning.

 

If you have the choice, try to avoid maintaining either very high engine speeds OR very constant. Some variation in speed on the highway will be fine to accomplish this. But in general, the breakin requirements have gotten a lot more lax now; so you're unlikely to really hurt the car with a long highway drive. (AutoX is another matter!) I mean, I guess it's not ideal, but if you need to go somewhere you need to go ...

 

I've read many newer cars do this, but if you try it on the Fit while watching the Ultragauge you'll see that coasting in neutral, at least on the MT, the fuel consumption is far lower. It's easily observable.

 

My ultragauge shows the injectors shut off when there's no throttle input and the rpms are >800, just like the fsm says.

 

Not sure how much more plain I can make this.. If the engine is idling because you are in neutral, fuel is being consumed to avoid stall. Therefore consumption is higher coasting in neutral, end of discussion.

If the injectors are off, you are not using fuel.

Rolling off the gas @ 40mph in gear:

Fuel scheme is showing a stoich burn @ 14.2:1 AFR.

Completely off the gas shortly after.. injectors off and the O2 sensor is pegged lean:


ECU indicates max lean, or 29.4:1 AFR but in reality its approaching infinity as there is no fuel but the sensor doesn't read that lean.

Duty line in yellow is Injector Duty Cycle, 0% = Injectors are off.

It's easily observable that you don't know how EFI systems work.

 

This! As long as your coasting fast enough that you don't need to give it any throttle to maintain your speed, just leave it in gear.

 

what is the gauge name in UG? I have blank location I can put it in.

 

Plus- in some places (NY, for one) it's illegal to coast in neutral and if you have some sudden reason to accelerate you may forget you're in neutral for a couple of seconds and miss the opportunity to avoid an accident.

 

does the tranny fluid circulate in neutral in those AT gear boxes to keep them running cool?

 

I've always thought this was the stupidest thing .. yes, you may forget you're in neutral. You may also forget you're in 5th instead of 3rd and you don't accelerate at all. You may forget that you are supposed drive on the right side of the road. But no one is suggesting that you spend all day only in 3rd gear or drive only on one way streets. Instead we depend upon drivers to operate the vehicle controls properly. "Illegal to be in neutral?" Why do they make cars with Neutral then? Maybe they should make it illegal to sell cars with Neutral. Or actually, making it illegal to sell cars with Drive would prevent a LOT of accidents! So that would be best. Yes. No driving. Stay at home. Much safer.

Baka!

 

To the best of my knowledge, there isn't a gauge for injector duty cycle. However, when they shut off, UG says that it moves to open loop and short term trims go to zero.

 

i suppose because cars weren't made to be driven in neutral..and neutral is useful when pulling car up a tow bed or what not, i guess... im a MT driver and i rarely use N while driving. only while coming to a stop from sub 10mph or stopped do i shift into N and clutch out.

 

Pushing a car in gear is a bit@# too...

Yes coasting in neutral is illegal. Coasting in neutral downhill is dangerous. Coasting in neutral on flat freeway is annoying as hell to all drivers around you (slow down speed up slow down speed up).

Neutral is for towing or pushing, and for MT drivers it's for stoplights. That is all.

 

yah, even while the car is shut off, my MT car is not in N.

 

uh... going to zero doesn't mean much for short term trim, since it can go negative too.

 

Right if its non-zero you are in closed loop. At least in my car it's rarely at zero, except when coasting.

 

Only if the driver is a boob. Forgetting to shift into gear is exactly as dangerous than forgetting to reapply the gas pedal. It's a lot less dangerous than forgetting to apply, say, the brakes. Luckily, those cannot be shifted into neutral.