Here we go again... EOC & automatics
 

Ok, so we have already established that Engine Off Coasting in an automatic means that your transmission fluid pump isn't running, and therefore the tranny is oil-starved. That means if your running one of these lovely AX4S transmissions (Windstar, pre 2005 OHV Tauruii and Sables) like Sean and I, it will eat a clutch pack, implode, and create a black hole that swallows all known life in the universe.

Anywaaaaay...
People keep telling me Minnesota is flat. I fail to believe them. The hills in Stillwater are so ridiculous that we have staircases connecting neighborhoods, and I can coast halfway across town if the traffic is light.
A friend of mine lives at the top of a long (1.7 mile) hill, and I always use first gear compression braking on the way down. On my down today, I realized that in first gear with the throttle closed, the Torque Converter is still locked, the alternator is still running, the vacuum system is still pulling, and the transmission fluid pump still runs

So I killed the ignition. At the bottom of the hill I turned it back on, and everything functioned normally the whole time! The engine cranked over smoothly on the cars momentum, no problems whatsoever. I never had to use the brake or the throttle for those 1.7 miles.

Oh, and I didn't have to rev match because the car was in gear the whole time.

So is there anything I need to know before I go ahead and install a kill switch?

Why doncha just click it into neutral?

Are you sure the engine isn't in fuel-cut mode in that situation already?

Compression braking

I'm not sure, but i could hear/feel it start when i turned the ignition on. If it were in fuel-cut mode, would it sound the same as 'off'?

Don't we need to distinguish between Engine Off Coast in Neutral (EOC-N) and Engine Off Coast in Gear (EOC-G)?

Yes. I'm talking about EOC-G for the reasons stated in the first post.

SHOZ on TCCA answered my question, do Taurii have fuel-cut mode?

"Yes they do. There is a strategy called Coasting Fuel Shut Off. Pretty lame with OEM tuning. I adjust this to be a lot more aggressive in my tuning."

So, yeah, kinda what I expected in a sedan rated 19 mpg city.

The Taurus has an odd behavior that you may have noticed...

Shifting to Neutral while coasting, increases RPM to potentially match the gear re-engagement. Same for downshifting from OD to D -- it actually speeds up and offers little compression.

I have some concerns about iGEO-CIA (In-Gear Engine Off Coasting in Automatics). [Acronyms are fun!]

The torque converter is locked with no fluid pressure to the remaining components. I would highly recommend flipping to neutral and use the starter. It's a lot easier to replace than a tranny.

-Rick

Why wouldn't there be fluid pressure? In D and 1, the entire drive-line is locked in gear and rotating due to the car descending the hill. In this case, the tranny should be getting more pressure than it would in normal driving because the crankshaft turns at 2500 rpm in 'D', rather than 1000 rpm if i were to descend the hills in 'O/D' with the hydraulic brakes.

I'm assuming the tranny pump is driven off the input shaft, but please, correct me if I'm wrong about any of this.

Unless the engine is physically turning, the tranny pump isn't pumping...

I would rather have a warm fuzzy by just neutral coasting an automatic, engine on. I would think engine off coasting in gear with an automatic would cause compression braking, and wear and tear on the restarts, etc. Not for me, sorry. Good luck on that. Way too much work and way too much risk.

Ok, first of all, the whole point of this is that I'm using compression braking anyway on the steep hills and stop-n-go traffic around town, so I want to cut the injectors while doing that. The car does have a fuel cut mode, but it is uber suck- I tested it today, the injectors run even when the brakes are applied.
Sorry if I sound condescending, I appreciate everyones input here and I'm just trying to get my objectives across.

99Metro- Do you mean the engine needs to be running, or simply turning?
I ask because with the EOC method I'm using, the engine is turning. I think the tranny pump is pumping whenever the crankshaft is turning. But, heh, I've been wrong before...

If the whole driveline is turning, unless you have an electric fuel pump, then yes, the tranny's pump is turning, thus, pumping.

One thing that anyone with an automatic tranny can do is to go to a dealer w/ the VIN of your car, and find out if it was equipped with a "tow-behind" package. If it was, you can coast, engine off, in neutral, and not damage anything.

The odds of this are highly unlikely, but you may be lucky.

Other than that, yes, if the crankshaft is turning, as a general rule, so is the tranny pump.

BTW, If you have a dead battery, coasting at 25 mph will start your engine in an automatic car... just like pop-starting a manual. (Except certain models, as is the case with all automatic "quirks")

Awesome,
I know I don't have a tow-behind package (she was a Hertz fleet car).
I'll just be using EOC during compression braking anyway, so everything works out!

Just remember that you don't need to hit neutral or use the starter to restart the engine... all you have to do is complete the circuit again (turn the key to "On" again).

The engine spinning without actually running will not affect it one iota... the oil pump is mechanically driven by the rotating assembly, therefore, it will still pump oil through the engine, and nothing will be harmed... in fact, in new engines, this actually helps to seat the rings, since vacuum in the engine block pulls the rings outward to the cylinder walls.

If you feel that you're slowing down too much w/ the engine off, push the gas pedal to lessen the vacuum on the engine, thus reducing compression braking. This will NOT flood a fuel injected engine.

Also, remember not to push the accelerator immediately after restarting the engine. The fuel pump will still be in "prime mode" and may flood the engine if you open the throttle.

I understand your cost-benefit ratio with using EOC -- I do the same with my automatic, but in Neutral. I've been told that fluid pressure for the lubrication system is absent and puts undue strain on clutch packs and other internals when forced to turn (especially at high speeds) while engaged.

I consulted the shop manual for my vehicle. In this instance, the main shaft should turn and provide pressure for the ATF pump. But, the Regulator Valve determines how much fluid is pumped and where. Here's the basic schematic for its operation...

General Hydraulic Pressure:

ATF Pump -> Regulator Valve into 3 outputs ->

-> Line Pressure (shifting action)
-> Torque Converter Pressure (engagement hydraulic coupling)
-> Lubrication Pressure (Where we want to focus)

The TC's stator rotates via torque from the crankshaft. In conditions of torque (engine running, acceleration), turns a shaft, moves the spring-loaded arm on the fluid pressure regulator and feeds the system with ATF.

As I understand it, torque converter pressure remains when the engine is cut because the regulator valve receives no torque and closes. Now, fluid cannot be pumped into the lubrication system. Clutch packs turn with the absence of sufficient fluid, and can be susceptible to accelerate heat and wear.

It's a complex operation -- if I'm incorrect in how I interpreted this system, then let me know :)

As always, every transmission model is different, your mileage may vary...

-Rick

Christ...
If I could mail someone a hug, you would get one! lol
Everything you stated is exactly what I suspected.
However, I did not know about opening the throttle to lessen the compression. Awesome tip! Thank you all very much!

RH77 - you're exactly correct, except one thing. When you're coasting and the engine is turning, w/ the throttle off, it doesn't do damage to the transmission, other than normal wear. By turning off the engine, and leaving the transmission in gear, you've effectively done nothing but stop the fuel consumption...

Engine is still turning, although not providing torque, transmission is still engaged, and therefore, pump is still working. One could confirm this by installing a pressure gauge inline w/ the tranny cooler. (Just a thought)

Also, a trans temp gauge might be beneficial.

If you doubt that this will not harm a transmission (anyone), you should also consider that in an automatic, the most effective means of slowing down and maintaining speed is STILL downshifting.

The torque convertor and clutch packs will not engage fully until engine RPM is speed matched to the vehicle speed per the gear, therefore, it's just as "damaging" as it would be to your clutch while doing so in a manual.

Oval Overlord - Hug accepted (even if you're a dude... I'm comfortable) Although I will tell you that you should not just take my word for it. Ask a "professional"... and not just one. Never just take one person's word for ANYTHING without verifying it, especially when that person is a screenname on a website or forum. Google is still your friend.

I shall ask the dealer mechanic!

That's the spirit! Hell, take him a print out of this thread, and ask if it's correct...

Cool -- if I didn't have to crank the starter, that would be great.

My EOC is often from highway speeds, to an off-ramp, and to a stop or below TC speed (35 mph). There are some instances where I coast down hills in TC lock speed and can key on to start the engine.

Other considerations -- a fuel injector cut switch can be installed.

Let us know what the mechanic says!

-Rick

RH77 - Your integra may not have a lockup feature which keeps the torque converter in constant lock (engine spinning) You'll have to drop a gear or two and find out... rule of thumb, converter locks at 2k RPM, so at 35 mph, you may need to be in 2nd gear.

I'm not sure of the implications of putting the transmission in gear in an auto while it's off... I doubt it would damage anything, but it just might piss something off, and open that black hole, or create a rip in the space-time continuum.... you never know. Again, consult a dealer. Except, in your case, go to a Honda dealer. They tend to be more honest than Acura dealers. *Acura is an american car... Honda is a Jap car produced in America*

I think I'll need to bring him cookies along with the thread printout, as a thank you for his time :-)

OO - Yes, that would be a nice gesture. Also, consider making friends with your dealer's service techs... they can help in ways you wouldn't believe when you need that $400 OEM part that can't be gotten anywhere but the dealer.

Example - Friend needed an ECU for his '94 NSX (Honda, not Acura) (Yes, there is a difference). Dealer part, end of story. Talk to dealer, $1600, and it's not even warrantied, shipped from Japan. (That's the difference.). Also, used.

Talk to another dealer that I buy parts from when they're cheaper or better quality, I can get the same ECU, again, used, from someone they know that just put an aftermarket tuning system in his car and didn't keep the OEM part... $300. (The cost of the tuning ECU he used.).

Lesson - Dealers will mark up anything they can get away with, especially when they know you can't get it anywhere else. Make friends w/the dealer, they'll cut you alot of breaks. That dealer I know could have (and by all rights, should have) charged us $1600 for that ECU. They didn't. Because I know them, and they know me.

Second Example - Back when there was still a huge craze going on with DSM products and the "crank walk" issue, a guy who always went to his local dealer for services bought a used Eclipse, outside of factory warranty, and it was suffering from the same issues. Dealer recommended long-block replacement, and he got a turbo engine in place of his standard 4G63, except the dealer didn't install the turbo. The whole job was covered under warranty, because they knew the guy. That would have made the car a total loss had it been work that was paid out of pocket. And he got to keep the Turbo, since it was the same one for his other car. (Also an Eclipse, always dealer serviced from day one, but GS-T model.)

See how you can benefit from this type of relationship? We all like to think that it'll never happen, but it could.

Yep, my American Make Acura was indeed manufactured in Japan (along with its Honda Integra counterparts). It has truly been a role model for durability and trouble-free, efficient operation.

I can't say the same of the new '03 Mitsu Evo-8 I once had. Sub-par build quality lead to transmission alignment issues and grinding on perfectly normal shifts. They sent a tech from Japan to diagnose and repair it. They fixed it, but it was never "right". Fun car, but problematic -- lots of warranty work and time in the shop. Complimentary rental base Sebrings were a terrible replacement during the repair time. I didn't buy that kind of "performance.

I once had a good rapport with the local Honda dealer when I ran Auto-X in a '99 Civic Si. They modified alignment outside of specs for superior handling and swapped summer tires for free. Best car (and dealer relationship) I had...

For Teggy, those days are long gone. I do most of the repairs myself, except for body work and perhaps the timing and aux belts/pullies/water pump. I may tackle that next time. Otherwise, a local shop may get my biz. A few dealers in the area are pretty crooked.

-Rick

If you were closer to me, I'd gladly steal your business from them. I'm cheap, because I do it for fun, and only look to get paid what I would want to pay someone else.

I don't pay myself for coffee breaks and the like, just work performed, and 15% markup if I have to get the parts, for my run time and trouble.

Oddly enough, I have trouble building a client base no matter where I go... people would rather get ripped off knowingly than pay someone to do it in their driveway.

I love working on these import cars though... it's so easy.

random fact about my transmission: With the car off, not moving, I can put the transmission in any gear and it will do nothing. IE on a hill it just rolls away. Now that's a static drop. I've also turned the engine off while traveling at slow speeds, as the engine output shaft drives the trans coolant pump. High speeds off not recommended by manufacture and aficionados alike. I've yet to muster the will to turn the car off while in any gear traveling at any speed. I don't think it'd end well, and I have no capital to find out.

As is the case with any other transmission in any car, anywhere in the world.

Very good, you've discovered gravity.

If you read back through the thread, you'll realize that vehicle speed does not make a difference. Try going 25 mph and using 1st range in your transmission. If it doesn't work in a second or two, you still won't damage your car, it takes several minutes to overheat the transmission.

High speeds off for EXTENDED PERIODS i.e. more than a few seconds.
Go test drive a car from a dealer. If it breaks during a test drive, it's not your problem. Or, you could just stop thinking that your car doesn't handle worse abuses every time you drive it, and shut the engine off while you're in 3rd range at 2500+ RPM.

I like your thinking Christ.....hate the handle choice though (not the representation, just the choice). Yesterday I almost did shut the car off in 1st just to try it, but I was too late in my thinking for my stopping destination, and then forgot after I got out. I had mountain bikes on my mind!

and now we have snow, so I'll have to delay the test till dry roads. slick as dog poo on linoleum.

check the thread "what's in a username". You might feel differently once you've read my post there.

Hint: I'm not religious...

Eh...
Bad news...
I went to Stillwater Ford yesterday. It doesn't exist.
I was there a week and a half ago to look at a ZX2 for sale. Now, the place is deserted. Apparently the parent company is on the verge of bankruptcy because its assets are tied up in Chrysler Financial.

SO, at this point, no definite answer on the EOC in 'drive' thing.

I'm pretty sure I'm going to drive my wife's car without her being in it with me, and find out what happens.

This, of course, won't answer the question definitively, since the only definite answer I get will be "does it work on a '94 Grand Prix SE w/ 3.1 MFI"

I'm sure someone will have an opinion differing from what happens if I get a positive result.

Neutral coast engine off automatic. IM IN UR FORUM MESSING WIT UR ACRONIMS

Hi all, Interesting discussion.

How long does it take for the bearings in an auto to go dry after the pump stops. I would imagine a helluva long time. The reason oil starvation in an engine can be quick and catastrophic is mainly the cylinder walls. They can go dry and cease pretty fast due to the heat and the rings scraping oil off every stroke. Then the piston stops and your crank keeps going. An automatic does not have these harsh conditions so the seconds that elapse during a reasonable coast could not possibly starve the bearings enough to do any damage... In my opinion. Also, in neutral there is very little pressure on anything, just rotation as far as I know.

If someone could explain how all that oil will magically evaporate then I might believe the anti coast theory.

Anyone?

Anyone actually experience a failure under these conditions?

I want to believe.

Hugs and cookies.

Most of the wear comes from needle bearings that aren't lubed as well as they could be from what I've heard, not as strong as ball bearings and not splash lubed means bad things could happen at any point in time. As long as it stays in N I don't think you'll see issues w/ the clutch packs.

Let me know what comes of that! I have a '93 Lumina Euro with the 3.1 MFI, and would love an answer!

Also note: I work in Bloomsburg - nice to see a (relatively) local!:thumbup:

I'll be sure to let you know what happens, as soon as I do it... unfortunately, that will require me coming up with an excuse to drive her car, which would also mean I have to stop being lazy and get up with her in the morning so I can take her to her rendezvous for her ride to school. (5 am is early.. wah.)

I can't think of where Bloomsburg is... and I wish I still had work LOL.

I'm up Route 11 from you, about 60 miles. If we want to go shopping and make a day of it, we'll go to Selinsgrove - that's closer to you, maybe you recognize that name.


I shut my car off in gear this morning. 35 MPH, was most likely in 3rd + TC lock (it was about 1500 RPM - don't know if it was 4th or 3rd + TC lock). Turned key back to run, and car kept coasting. Engine did not re-ignite; I had to shift to N and manually re-start.:confused::(

was the engine still spinning while the car was off? You'll feel/know the difference immediately if the engine is still spinning, not to mention that when you turn the key back on (or in some cases, even while it's off) the tach will still show RPM immediately.

If you're in lockup mode, chances are, you're not going fast enough for it to work.

Since you have a tach, drive in 2 or L until you get up to about 2000 to 2500 RPM, then shut the key off and leave it in gear.

As soon as you turn the key off while you're in lockup mode, the TCM/ECM unlocks the torque convertor.. it's an electronic feature. Which means that you're way outside the realm of the engine starting back up when you turn the key back on.

No, it was definitely off - felt it cut out and tach dropped. I have to run out for lunch today from work, I'll possibly try it then.

Keep us posted.