I have a 2010 Sport Fit and try to save gas by coasting when possible, I read something on the web that said I was doing the opposite because the fuel injectors were sending gas the the injectors when in neutral. Is this true?

 

If you are in N, the only way to keep the engine spinning is to keep sending it fuel. On hybrids, the car can turn off the engine when it's not needed because it has a large battery to restart it as needed. If you are engine braking, on some cars, the car will turn off fuel because it senses that the wheels will keep the motor going. No idea if or how this works specifically on the fit.

 

Yes the injectors still send fuel to the engine or else it would stop running...granted you are using less fuel but I personally like the option to accelerate quickly if I need to. I has saved me from a few accidents in the 20+ years I have been driving.

 

? Malraux. thanks for the reply, so are you confirming that coasting in neutral is not saving gas because the injectors are sending gas even when in N?

 

We had a 1971 Saab 99 with a four-speed manual transmission. It was designed to free-wheel in gear whenever you took your foot off the gas. You could always coast going downhill. There was a lever by the shifter. If you pulled it back, that feature would be disabled and you had engine braking. When you were done coasting along, you'd simply press on the accelerator pedal and bring the revs back up to match the speed of the car. I have no idea how that worked but it was seamless.

It had an early Bosch EFI system with a shoebox-size computer that ran it. I know the injectors squirted fuel whenever the engine was running because the reinforced rubber hoses from the fuel rail to the injectors always leaked because the fuel pressure regulator was unreliable. All of that ancillary stuff was analog, of course, so you could fix the regulator by hitting it with a small, ball peen hammer. If an injector stuck you could hit that, too. If you hit it too hard VW parts were interchangeable and much cheaper.

I'm sure the Fit works the same way without the freewheeling.

By the way--when that transmission failed (in 1974) it cost $1100 to repair. That's more than $3500 in today's dollars. That's what I think about when people ask about coasting.

My wife says that the Saab had the most comfortable seats of any car we ever had and it's a good thing because we spent so much time sitting in them while we waited for a tow truck.

Anyway, I never coast along in the Fit. I get almost 40 mpg most of the time anyway. Who cares?

Holy cats. Reading back over this post I think I lost my mind.

Cheers.

 

Well, when you are in N you are still using gas, if that's what you're asking.

 

yes that is correct!

 

I've never understood this discussion and why people think it's an either or situation.

The engine is using fuel when coasting in neutral, but you are also saving fuel if you do it correctly. It's not if the engine is using fuel or not, but how much fuel is it using to cover the distance in question.

Say you see a red light 1/4 mile ahead and you're going 40 mph. Your three options are, continue driving at a steady speed, let off the gas while in gear, or coast in neutral.

Continuing to drive at a steady speed certainly uses more gas than the engine idling while in neutral because it requires power to spin the engine at more-than-idle RPM, overcome drivetrain losses, push the car through the air, etc. And if you end up hitting the brakes, you just dumped the energy that was in the gas into waste heat in the brakes.

You can let off the gas and leave the car in gear which will shut off the injectors, but engine braking means you don't travel nearly as far as coasting in neutral. So either you're driving closer to the light at steady speed (using fuel) before you can start coasting in gear, or you coast in gear and come to a near stop too soon and then have to give it gas to go the rest of the way.

Coasting in neutral can allow you to cover quite a long distance while using very little fuel. That's not to say that there aren't safety issues to consider or whether it's "worth it", but it can save fuel. Of course, the hypermiling technique of coasting with the engine off saves even more fuel but is definitely more dangerous. There again, the worth-it-or-not argument comes up.

 

Not that it really matters a lot, but [in California] it is illegal to coast in neutral.

Wouldnt it save the exact same amount of fuel as if you had the clutch depressed in a MT? I do this a lot when going down hill and it doesnt have the same safety ramifications.

 

im confused why is it illegal in california to coast in neutral?

i always coast to red lights then when it turns green i either shift to 2nd or 3rd

 

"Coasting in neutral" is if you had the MT *not in any gear* and were coasting without the clutch pedal depressed. Its a safety issue as you could not as quickly or easily accelerate if required as compared to having the stick in gear with clutch pedal depressed and could potentially give it some gas and let off the clutch to accelerate out of trouble if needed.

Having the stick in gear and clutch depressed achieves the same effect as 'coasting in neutral' but is considered a safer solution for a MT.

The same or similar law is likely in effect for many other states but I live in CA and dont care about any other states

 

thanks i always coast and i dont think that will change, it makes sense to leave in gear and clutch in, incase something happens.

 

I coast a lot too and that shouldnt change, its part of the beauty in a MT. But the safer method should at least be known, even if you choose not to do it all the time.

 

learn something new everyday. i did not know this haha. i will continue to coast as usual tho.

 

The only way you are SAVING fuel is if you DONT drive at all.
When you are driving, either in neutral or in gear, you are USING fuel. You use the least when the engine is at idle speed which happens when your manual transmission is in neutral given you are not pressing the gas pedal for no reason.

 

Keeping the clutch pressed in for long distances inflicts a tremendous amount of wear on the throw out bearing.

 

Two things about coasting. first of all, in many states it is called Freewheeling and I believe it is illegal in all 50 states. when the car is not in gear, you do not have the same level of control. Granted you can create the same situation by keeping the clutch depressed (insert sad comments here ) but it is hard on the transmission as others have noted and it's not the intended use for the trans (shifting is).

Second, if you are not applying pressure to the gas pedal, there should be no more fuel used than if you are freewheeling as the computer is providing only enough gas to keep the engine running. (also, unless you rev-match perfectly when it 's time to shift back into gear, the chances are you'll either use too much gas engaging the clutch at a higher rpm than needed, or will engage too low initiating engine braking - wasting some of the gas you saved).

On slight downhills, I recommend keeping your foot on the gas just enough to prevent the car from engine braking. This way you are using minimal fuel, keeping the gears engaged for safety reasons, and also don't have to worry about rev-matching exactly so you don't negate your fuel savings.

~SB

 

The only time I shift to N is when I'm sitting at lights that I know are particularly long. I don't know whether it saves anything, but I do it. I don't use N at any other time while in motion. The Fit will give you the best mpg simply by keeping speed steady. Whether it's 30mph or 70, keep it steady and don't gas on/off with your foot like so many people annoyingly do, and you'll get the best return of mpg's from the Fit.

Dan

 

No, he said that while the injectors are squirting gas to keep the engine running it is using much less than if you were in gear and under power..

This morning I needed to use my hybrid with the icebears and started the engine half hour before driving and the average mpg display didn't change from when I started the engine til I drove away and then increased as I drove on. About 120 miles on that tank. Hard to believe.
Idling isn't the best for engines but if you need to clear the windshield ...

 

I recall reading an article about this that was released by Toyota and confirmed by GM and several other manufacturers. Long story short, above rougly 25 mph, the wheels turning through the transmission are able to keep the engine going without stalling out and the injectors shut off. Shifting into neutral causes the engine to go to idle and necessitates the injectors to kick back on or the engine will stall out (obviously).

My current car is a 2010 Hyundai Santa Fe and it has an 'ECO' indicator on the dash. I find it incessantly annoying so I keep it disabled but when I have had it on, coasting in gear causes it to light up but if I shift to neutral, it goes out. Just some food for thought.