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Shifting into neutral at stop lights


Guest F14CRAZY

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Why? If at idle speed it shoudn't do any harm and I do just that if sitting a long time, like waiting for a train etc.. Beyond that, I don't see a purpose. The ignition timing drops back a few degrees if idling in park/neutral, and there will be a slight increase in trans. fluid temperature after a prolonged idle in gear. I doubt there is any significant difference in fuel mileage, plus I prefer to be able to move instantly in case the situation demands it in traffic. Just random thoughts.

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Guest F14CRAZY

Thanks guys so far. I should have included it too, but what about manually downshifting when coming to a long stop? I was thinking that maybe either (neutral or downshifting) would save the brakes but then again the whole car is designed for that, and the brake wear difference would probably be superficial anyway.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I was thinking that maybe either (neutral or downshifting) would save the brakes but then again the whole car is designed for that, and the brake wear difference would probably be superficial anyway. </div></div>

I would rather replace $30 brakes before I replace a $2,400 transmission confused.gif save the TRANSMISSION!!

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dah, that is the reason that truckers always use a lower gear when going down hill. To save the brakes. Well, almost. If they just used their brakes they would overhead and then have no brakes at all. The reatta is sorta a different animal. At least my Reatta is. Try this for kicks and giggles. Put the guage screen on and notice the rpm at say 50 mph. Then put the car in nutral. If your Reatta is like mine the rpm will not go back to idle 650-750 as you would think it would. In my case that is why my Reatta seems to drift so well when you take your foot off of the gas pedel. My system is still giving the motor some fuel and it takes a while for the car to slow down. Would someone do this test and post your findings........ken

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RPM stay around 1500 in neutral coasting at 50 mph or so. Read the counts for the IAC and it will be elevated. I am not certain why it does this, possibly to keep the engine close to the rpm it would be in for the speed and gear for smooth transition when shifted back into gear? I don't believe it turns the injectors on an off like it does coasting down in gear.

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I think that it has more to do with anti-pollution stuff. Can't explain it, have just heard it. Something to do with keeping combustion temperatures up or down???

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SO. at least a few Reatta and probably all do the same thing. When you take your foot off of the gas The system keeps giving the motor gas. This hard on brakes. Padd. What is the answer to stop this.........ken

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">SO. at least a few Reatta and probably all do the same thing. When you take your foot off of the gas The system keeps giving the motor gas. This hard on brakes. Padd. What is the answer to stop this.........ken </div></div>

I suspect the amount is negligible. Similar in function to a dashpot used on carbureted engines with automatics.

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On coasting, don't you want the engine above stall speed to keep the tranmission pump with pressure?

When I first aquired my 90, the shift pattern was wrong. When I came over a hill and let up on the gas the car would start to coast/ freewheel. It felt like a manual in neutral. It took a while for the engine and tranny to hook up if I needed to, not a good feeling. After some tweaks to the cable linkage and the vacuum modulator, I got better control with some feedback from the engine/tranny connection. If I remeber well, there was a tremendous amount of engineering put into getting that feed back in the early days of automatic trannys.

On neutral at stops, that is what the stall speed torque convertor is for is it not? Since it is a fluid slippage no wear to parts but fluid pressure is maintained. I,d get distracted and forget to put it back into gear anyways. The only time I've done this was when the TCC was not dis-engaging and causing the vehicle to stall.

Vic

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not so. with the dashpot the motor returns to idle in just seconds. The reatta will drift for miles with the rpm much higher than idle. When I take my foot off of the gas pedel I expect the motor to start holding the car back. The reatta is like the [bunny] it just keeps on going and going. ken

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I think that it's actually -- at least potentially -- bad for many of the moving parts in the drivetrain...

The obvious is the wear on the gearshift linkage.

Not so obvious would be that due to the change in 'slack' when the transmission is again engaged with the engine; the parts in question would be the CV joints, the final drive ring and pinion (hey, the Reatta DOES have a ring and pinion, is this right?), and the servos/bands in the tranny.

Another issue might be the changing of angles of the engine pistons in their bores between upstrokes and downstrokes (anyone remember talk of this effect, especially with respect to lugging and braking with the engine on a manual transmission... and a reason that auto trannies are easier on engines?).

K

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"When you take your foot off of the gas The system keeps giving the motor gas."

This is the DFCO or Decelleration Fuel Cut Off that opens the IAC during deceleration to control emissions. It is a subroutine in the ECM. I *think* we got it turned off in Greg's car (obviously undesirable with a manual transmission used for engine braking).

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