EOC on the highway, some questions
 

I've been getting a little bolder about EOC, i recently started doing it on a couple good spots on the highway. What I normally do is get up to 60 (keeping my instant MPG >35-40), turn the engine off, coast (in neutral) down to about 52, and bump start into 5th gear

1) is this hurting my car? is there a better way to do it? should I not be doing EOC at those higher speeds?

2) I just read another thread about messing up an engine if doing EOC by shutting off the engine.....is this an issue with newer cars (ergo, my '09 cobalt?) I gathered that I should be letting the engine drop to idle before turning off the engine...is that enough?

listen.. i;m not the expert, but i just wouldn;t do it. there;s been a couple people that commendably wrote-in to say they regret it. -- it cost them their transmission.

i was doing engine on coasting in nuetral in my old accord since late september.
i got a new timing belt in september. my new belt is starting to squeal since december.

it;s very rare i engine on coast, now.

This is only an issue for carbureted engines. For fuel injected engines, there is no risk of sucking extra gas into the combustion chamber when you kill the injectors.

I recommend a kill switch instead of cycling the ignition, mostly because all your computers - airbag, ABS, ECU, etc. power down when you turn the key.

Personally, I don't feel that P&G pays at high speeds, unless I'm headed downhill, but that's your call to make.

I P&G all the time. Thats one of the major reasons I get 200%+ EPA rating in summer. I've been doing it for over 20k miles, no adverse effects so far. Most of the miles I travel are highway.

15k with lots of EOC with my Honda... but then, if I break it, I own it... :)

I need to address this, because I feel that it could be misleading to anyone who doesn't know any better.

Your timing belt is not affected by whether or not you are coasting with the engine off, on, or otherwise. Your timing belt also does not squeal. Squealing is a sign of belt slippage. If your timing belt were slipping, your engine wouldn't be running. Period. Full Stop.

Also - You won't lose a transmission using EOC in a manual. They're designed to be splash lubricated, and some part of the transmission is always churning fluid when the vehicle is moving. In case nobody noticed, he "bump starts in 5th gear." That means he's got a clutch.

I also recommend a kill switch. If you're bump starting correctly, it won't cost you a cent in clutch repairs, because the clutch will still last the 5 years it's supposed to. If you're screwing it up, prepare for a repair bill. There is mention on this site in several threads about the proper shifting technique and clutch starting for manual transmissions. If you're unsure about how you're currently doing it, I suggest you read up and avoid a head ache.

Those things said, EOC will help any time that you have more space than you would travel by just letting off the gas. Pulse and Glide (what you're describing) usually won't work at higher speeds, because aerodynamics tends to eat a big chunk of your engine's output just trying to accelerate. If you're noticing higher numbers on your eco-meter, chances are, it's working for you, but not everyone will see those same results. [I know I freakin' didn't... :'( ].

By the way, in case nobody said it yet, as always, no matter what the situation, YMMV - Your Mileage May Vary.

Nobody's going to have the same experience you have, so your best bet is to do some research, form an opinion, then test it yourself. Nobody will be offended if you don't just take their word for it here. We're all adults. Most of the time. :)

Same here. 175,000 total miles, 30,000 with P&G, and not a hint of clutch or transmission trouble.

Burnt -

I've been doing strategic EOC for about 75K miles. No known problems.

CarloSW2

"Oh crap! There's a good spot! [panicked engine shut down..... bump start] Whew - good strategy, team!"

At least that's what I used to do. LOL.

Been doing EOC for years. Late last summer I had my engine and transmission (with original clutch) replaced. The transmission had 512,000 miles on it, of which over 200,000 miles had been with EOC on every downhill and when coasting to stops. The clutch still had about 1/4 of its lining left on it.

Before I started doing EOC I read everything I could find about it on this site; I didn't even know manual engines could be clutch started. I spent some time in a parking lot practicing before I felt comfortable with it on the road. I have noticed some increases, although it's only been one tank so far with regular EOC. I just saw that thread about engine damage from EOC and I got a little worried, which prompted me to make the thread.


Robertsmalls is right, each time I turn the ignition off all my electronics etc cycle off/on too, which is kind of a pain. I am planning on having a kill switch installed this summer, once I can scrape some money together (I know squat about mechanics, so I don't think I could install one);

Well, the engine damage, from what we can tell, is caused by fuel dumping. You won't have that trouble at all, no matter what engine speed you shut down at.

If you can do basic maintenance, and know how to use a wire crimper, you can probably install a kill switch without too much drama. The hardest part is the research, believe it or not. If you need help when you get around to doing it, there are plenty of people here, myself included, who are more than willing to help you out to the best of our ability.

The basic idea behind a kill switch is to stall the engine. There are a few ways to do that, but some of them aren't safe. If you kill the ignition only, you end up with fuel dumping. Same thing with choking it out. Really, you should kill the fuel. That way, the ignition system keeps working and ignites whatever is left of the fuel that already made it into the engine, so you're not pushing raw fuel out your exhaust.

Only conceivable problem with injector cuts on an OBD-II vehicle (yours, for instance) is that you might get a CEL if you cut the injectors directly w/ the switch. It should go away immediately after restarting, though.

I'm new to this and having a little troble finding a definitive answer as to we
ther eoc is safe or not in my aoto yaris,, most of what I'm reading is leading me to believe that engine off is harmful to the auto trans,, ?

What about coasting in neutrrel with engine on?

Coasting in neutral with the engine running is fine, as it keeps the tranny pump turning, so everything is lubed.

EOC varies by tranny. Some autos will lube well enough when spinning freely with the engine off, others won't.

I believe the Yaris is one you should NOT eoc. Engine-on neutral coasting is fine.

What about my Dakota? It has a "thunk" when I put it back in drive from neutral... this is EOnC, not EOC.

You probably have a bad engine/transmission mount.

Re. coasting with an auto tranny.
Look in your owners manual re. having your car towed.
Look in the section on "Flat Towing", where all four wheels are on the road and turning.

Most manuals should tell you whether it's safe, and limitations on distance and speed.

The reason to read that section is - flat towing an auto-tranny car is essentially the same as engine-off coasting it. Wheels are turning and the engine is off, with trans in neutral.

Some car's manuals will say never do it, always have the drive wheels off the ground. Some manuals will say you can go up to 30 mph or 40 mph, and for a distance of x miles. You get the idea. Now they're assuming the car is being towed so they probably figure you do it rarely. If you're using it as a driving technique - that will be daily, or nearly so. You might want to limit your coasting to lower speeds and distances than the manual gives you. Tranny failure is expensive indeed.

Better yet, buy a stick shift car next time if you're able to drive it!

I couldnt connvince the wife to learn:mad:

other wise i've always preffered mt's even before i started trying to increase mpg's