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-   -   Idling in "D" or "N" - more economical? (http://www.jeepgarage.org/f73/idling-in-d-or-n-more-economical-41618.html)

markp99 05-03-2012 07:50 AM

Idling in "D" or "N" - more economical?
 
When sitting at a red light, is it more economical to flip the Jeep to "N", than leave in "D"?
  • The Jeep seems to be "working" against the brake in "D", work equates to fuel, right?
  • RPMs are slightly higher in "N" compared to "D", consuming more fuel?

I am guessing the difference is pretty minimal, just curious.

Any thoughts?

amill 05-03-2012 08:12 AM

Re: Idling in "D" or "N" - more economical?
 
No measurable difference. Just keep it in drive.

padgett 05-03-2012 08:27 AM

Re: Idling in "D" or "N" - more economical?
 
Is most ecomomical to shut the engine off at a red light. Some manufacturers do this automagically.

Aiyer 05-03-2012 08:32 AM

Re: Idling in "D" or "N" - more economical?
 
On my last Jeep, I have always put the vehicle in N when I stopped at lights. The tranny on it still shifted smooth even at 165k miles when I sold her. I still do that in my current Jeep. It could be a habit from driving manual tranny cars for many many years. Besides, I feel like I holding back the vehicle when it trying to go forward if the vehicle is in D. My personal opinion is that it is just putting unnecessary strain on the tranny when it wants to run but the brakes are holding them back. Others might think I am crazy... so does my wife. :D

padgett 05-03-2012 08:52 AM

Re: Idling in "D" or "N" - more economical?
 
Tell your wife to think of an eggbeater. That is what is going on in the torque converter when stopped in drive, half is spinning and the other half is not which churns the transmission fluid. This loads the engine (uses more fuel) and increases the tranny temp.

True, the load and increase is minor, but is what is going on.

armoredsaint 05-03-2012 09:19 AM

Re: Idling in "D" or "N" - more economical?
 
I put it in "R" for tailgaters when stopped ;)

markp99 05-03-2012 09:38 AM

Re: Idling in "D" or "N" - more economical?
 
Quote:

Originally Posted by armoredsaint (Post 623693)
I put it in "R" for tailgaters when stopped ;)

Ha! In my old pickup truck (manual) I was actually able to engage the back-up lights while moving forward at full speed with the shifter without grinding any gears. This always seemed to get the full attention of tailgaters on the highway!! :D

Archer9 05-03-2012 10:27 AM

Re: Idling in "D" or "N" - more economical?
 
Shifting causes unnecessary wear on the transmission shift unit which is a known problem on some models. If I'm stuck waiting for a train or something or even at the drivethrough pick up window at McDonalds I'll turn off the engine completely. For red lights I just leave it in drive. Automatic transmissions have been designed for that.

Aiyer 05-03-2012 10:37 AM

Re: Idling in "D" or "N" - more economical?
 
Quote:

Originally Posted by armoredsaint (Post 623693)
I put it in "R" for tailgaters when stopped ;)

I can't find that on my Jeep. Did you add an aftermarket? ;) hehe

suzieque 05-03-2012 04:58 PM

Re: Idling in "D" or "N" - more economical?
 
Quote:

Originally Posted by Archer9 (Post 623719)
Shifting causes unnecessary wear on the transmission shift unit which is a known problem on some models. If I'm stuck waiting for a train or something or even at the drivethrough pick up window at McDonalds I'll turn off the engine completely. For red lights I just leave it in drive. Automatic transmissions have been designed for that.

this is what I prefer to do as well.

have you guys noticed that it takes a couple seconds to shift into drive after starting the vehicle?

even shifting from park to drive when running won't instantly engage, again takes a second to realize I've shifted to drive.

I'm wondering if this is normal, it really annoys me that I cannot start up and slam it into gear. Maybe its a quirk with the WK, thought I'd ask.

Yeti 05-07-2012 12:16 PM

Re: Idling in "D" or "N" - more economical?
 
My 2000 WJ has that delay when shifting into drive too. I don't recall my '96 doing it. It probably has something to do with "shift by wire"?

Antonio186 05-07-2012 12:56 PM

Re: Idling in "D" or "N" - more economical?
 
^^^^ this is exactly what it has to do with. everything on these damn vehicles are controled by the computer.

thats why i have a certain dislike for the 05-current Mopars. thats why i like my WJ's actual electrical circuits. with relays and switches. not encoded data streams over a vehicle network like CAN-BUS


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