EOCing with an Automatic

[JohnnyGrey]

Johnny how in the hell did you know my vehicle ran @ 2200rpm @ 55mph, you are dead on ... Just curious?

I didn't know that your vehicle had that ratio, I knew that my Cavalier did.

Even if you're not going to do any highway P&G, using the top gear will minimize the shock to both you and the drivetrain when bump starting, and should be effective down to 10mph.

[dcb]

Originally Posted by JohnnyGrey

Simply selecting the gear will start the car, there's no need to lock the converter. I'd choose top gear for this.

Originally Posted by JohnnyGrey

If you can do 2200 rpm @ 55mph, bump starting at 10mph will crank the engine at 400 RPM, which should be enough to revive it. Bump starting at lower gears will be increasingly violent, especially when you don't have the PWM modulation the ECU does.

Say what now? Don't lock the converter but you will have violent starts without the PWM, and who cares when you are performing possibly destructive testing on the auto trans anyway so you have an excuse to swap in a stick shift?!?

[trikkonceptz]

WHOA !!! If I understand you guys correctly, you are saying that by having the key on, if I slide the car back into drive the car will start up again? Is that Bump start?

[JohnnyGrey]

Say what now? Don't lock the converter but you will have violent starts without the PWM, and who cares when you are performing possibly destructive testing on the auto trans anyway so you have an excuse to swap in a stick shift?!?

Yes, there's no need to even touch the lockup. If not PWM, at least a resistor of some kind could be used to soften the startup. Just because he may swap a manual in doesn't mean he wouldn't be able to defray the cost of the swap by selling a functional automatic.

WHOA !!! If I understand you guys correctly, you are saying that by having the key on, if I slide the car back into drive the car will start up again? Is that Bump start?

It may or it may not. It depends on your ECU. On my 98 auto Cavalier, it will not bump start. The transmission is never in gear when the engine is stopped, regardless of shifter position.

[dcb]

Originally Posted by trikkonceptz

WHOA !!! If I understand you guys correctly, you are saying that by having the key on, if I slide the car back into drive the car will start up again? Is that Bump start?

That probably won't do it. Don't know about your car, but the saturn had actual solenoids to select the gears when it was auto, and of course a "solenoid" to lock up the torque converter, so with a couple switches you coud select a gear and force the engine to turn over regardless of speed (bump start), the unknown is if it will actually handle operating in that mode for very long

[Harpo]

My Civic says keep flat towing <35mph.

While I've done my share of EOC now, I can say I find that driving primarily with DFCO (Deceleration Fuel Cutoff) has biggest returns for me. Then if I'm going to stop for over 30 seconds, I'll kill the engine in the final deceleration <30mph if it'll be a stop. Keeping it OFF at the few long lights I encounter (3, 3 and 5 minutes respectively) have big effect on daily averages.

The weeks I experimented with EOC exclusively, only got me moddest gains, and I was more efficient sticking with DFCO ops. There are glide differences between DFCO and EOC, but if you feather the throttle with DFCO you can get in and out of DFCO if your short of your target roll distance with minimal FF.

My last three tanks have me at 45.5mpg with just DFCO operation and EOff at long lights. I have my route well planned which is key for DFCO.

[NoCO2]

It is my understanding from reading some articles on flat towing and some other articles on mis-matched forums here and there, that the only harm that comes from flat towing a car that is not meant to be flat towed is that the tranny fluid isn't cycled properly and thus the parts can heat up in the tranny if it's for extended distances. However, most EOCers don't go usually more then maybe 2 miles TOPS which is hardly long enough to cause any heat to build up in the tranny and cause any real damage.

My understanding is that cars that are capable of being flat towed when put in neutral actually completely disengage not only the engine from the tranny but the wheels as well so that the parts in the tranny stay stationary and don't create heat.

So, this is what I go by, if you want to be really cautious, just leave your engine running to keep the fluid cycling, otherwise don't EOC.

Now, P&G is a different story, since you're constantly going back and forth from neutral EOC to powered operation, you might cause enough heat to be generated to cause damage. Personally, I don't P&G in my Camry simply because it's annoying to do in an automatic anyway. But again, take it with a grain of salt and use the info as you will.

[IndyIan]

I use EOC on 3 big hills in my commute with my auto trans, I do use the starter to restart though. On the hills I get about 1.5km of glide so the car is off for only a minute or two and I don't think this is going to hurt anything, as I don't think auto transmissions use pressurized oil for the bearings, and even if they are there is no load in the transmission, everything is spinning freely.
I guess its a bit of a risk but I'll take it. Even people with manual trannys doing a EOC in pulse and glide are "abusing" the engine. Running the engine at low rpm, high throttle puts additional stress on the cooling and oiling systems, and then suddenly the engine is shut off not allowing the coolant and oil take heat away from the internal hot spots. On any high performance racing type engine this could quickly kill it. Fortunately passenger car engines are over built (or understressed) and we can use them this way. I'm going to assume my automatic tranny is the same and can take some "abuse" for 6 minutes a day.
Ian