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Old 03-06-2007, 09:52 PM   #21
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shutting off the engien is pretty risky (and illegal in most states), you loose braking power and power steering making it hard to do an emergency stop/maneuver if you have to.
that and the fuel you saved from idling just gets burnt up when you start it anyways...(takes more fuel to start a car than it does to keep it running, just liek an electric motor, takes more amps to get it to go than it does to keep it going) if you coast in neutral with the clutch released the engines idling will accually slowly spin the tranny fluids in a standard tranny and help it coast a bit better.
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Old 03-07-2007, 05:48 AM   #22
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...(takes more fuel to start a car than it does to keep it running, just liek an electric motor, takes more amps to get it to go than it does to keep it going)...
Leaving your car running wastes gas, period. The break even point is measured in single digit seconds.

Actually it costs ZERO fuel to bump start a car (assuming you have enough momentum left). And using the starter is, what, 300 amps for 1/2 a second? Whats that, 0.003 Kilowatt hours?

Hybrids turn the engine on and off ALL the time and propel the vehicle with motors, same losses exist there.
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Old 03-07-2007, 06:22 AM   #23
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Can't you put the car in "N", shut off the engine, and then key start the engine when you're done the coast? That's what I was doing in the Silverado and Intrepid.

This is what I did in my previous car, but it is so much easier to just bump start with a stickshift.
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Old 03-07-2007, 10:08 AM   #24
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Leaving your car running wastes gas, period. The break even point is measured in single digit seconds.

Actually it costs ZERO fuel to bump start a car (assuming you have enough momentum left). And using the starter is, what, 300 amps for 1/2 a second? Whats that, 0.003 Kilowatt hours?

Hybrids turn the engine on and off ALL the time and propel the vehicle with motors, same losses exist there.
but it also causes alot of stress on linkage parts to bump start a car, but when you start a fuel injected car the pcm spurts a bit of extra fuel to get it going again. it primes the system to get the fuel psi back up.

ever just turn your key on the on position and hear the slight whine comming from the fuel pump?
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Old 03-07-2007, 10:25 AM   #25
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but it also causes alot of stress on linkage parts to bump start a car, but when you start a fuel injected car the pcm spurts a bit of extra fuel to get it going again. it primes the system to get the fuel psi back up.
you need to quantify your objections, does turning the engine over with the wheels cause more stress than accelerating? or downshifting and engine breaking? most experienced drivers do it very smoothly using a higher gear. Yes there is SOME wear, but please ensure you do some homework before you make claims like "a LOT of stress" or imply that it is ALWAYS better to leave a car running.
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Old 03-07-2007, 10:47 AM   #26
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i have never once said that leaving your car running is always better. long hills yes it prolly would be more efficent to turn the engine off. but you loose braking power and steering ability(not all the way but its harder) why downshift? just coast...or leave it in whatever gear you were in and let it engine brake.

maybe theres not alot of stress but there is some as you say(prolly depends alot if its fwd vs rwd), years of doing this could possibly shorten the cars life/certian parts. and then you got a possible costly repair bill so theres where all your fuel saveings went...
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Old 03-07-2007, 11:15 AM   #27
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Hi VetteOwner -

I think you'll find that a significant number of GasSavers are using engine-off coasting, where safe & appropriate. The people who do this are seeing the highest fuel economy, because it happens to be a technique which can have a big impact on fuel consumption.

If you search on this topic, you'll find that the objections to using the technique have come up in various threads already. EG. the issues of power steering (many of us don't even have PS) and brakes (in most cars, the vacuum reserve is adequate for several assisted brake applications with the engine off).

Quote:
when you start a fuel injected car the pcm spurts a bit of extra fuel to get it going again. it primes the system to get the fuel psi back up.
This doesn't apply if you're installed an ignition kill switch. (Something that more than a few people have done.)

It's a matter of weighing the pros & cons and deciding what you're comfortable doing or not.

Welcome to the site, btw!
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Old 03-07-2007, 11:50 AM   #28
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"It's a matter of weighing the pros & cons and deciding what you're comfortable doing or not."

that is true and also i think the natural landscape of your area has an impact. but i live i Illinois and its extremely flat here...except for one kinda big hill and another going back up from almost a dead stop (right off an on ramp every morning) i usually just get up to 40 then hold it there... theres no truck lane either.
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Old 03-07-2007, 04:25 PM   #29
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VetteOwner -

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Originally Posted by VetteOwner View Post
"It's a matter of weighing the pros & cons and deciding what you're comfortable doing or not."

that is true and also i think the natural landscape of your area has an impact. but i live i Illinois and its extremely flat here...except for one kinda big hill and another going back up from almost a dead stop (right off an on ramp every morning) i usually just get up to 40 then hold it there... theres no truck lane either.
I think that for you, you could use the pulse and glide technique, with or without EOC, to improve your MPG.

My issue isn't the hills, it's the traffic density. I just had by farrrrrr the worst commuting day since joining GasSavers because of a double truck crash on the 105 that closed 3 out of 4 lanes. I was constantly just barely moving *up* exit ramps with cars and Semis stacked up like cordwood. If I had wanted to EOC, there was no place I could have done it. When things were relatively flat, I seriously considered getting out to push the car along . A Toyota Prius would have loved this traffic !!!

I have the power steering/power brakes issue. I only use EOC sparingly on straight roads where I *know* the behavior of the stoplights. For freeway speeds, I don't feel comfortable giving up my power brakes, there's just too many things that can go wrong. If I was better under the hood, I might venture to switch the car to a manual steering configuration (hate power steering anyway). Think I'll add that to my todo list ... done.

The ignition kill switch is da bomb, but I haven't done that yet. I have gleaned that in my traffic situation, where I need the power brakes, I could "EOC in gear" and maintain my power steering and brakes. This is an emulation of what some car manufacturers already do; that is, when the driver hits the brakes while the car is in gear, the ECU/PCM stops injecting fuel into the cylinders.

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Old 03-07-2007, 08:04 PM   #30
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...The ignition kill switch is da bomb, but I haven't done that yet...
I just did it on our 97 sw2, I found an "inj" fuse under the hood and put a micro switch inline with it and glued the switch to the auto shifter (index finger friendly position), bada bing.

(ok technically an injector kill switch, even better)
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