Lunging during de-acceleration

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Old Jan 30, 2008 | 09:05 PM
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Lunging during de-acceleration

Guys, I just got an '07 Type S and have noticed when the car is de-accelerating (on it's own) and slowing down to a stop that the car "lunges" some at about 10,000 to 15,000 rpm. What do you think? Is this something that can be corrected at the dealership? What do you suggest I do? Thanks, in advance.
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Old Jan 30, 2008 | 09:30 PM
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I believe actually normal, it's to assist in braking. also grade logic makes it seem like the tranny's acting up. (i think that's what it's called) It scares the piss outta me though as I always think my tranny is shot........
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Old Jan 30, 2008 | 09:36 PM
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read the owner manual on transmission operations
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Old Jan 30, 2008 | 09:53 PM
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I've read the owner's manual. It didn't help much. That's why I posed this question. I would like to hear from Type S owners and find out if they've had this experience too. Please don't tell me to read a manual...that's lame. If you don't have a solid answer to my question, don't post. I'm looking for owners who know what I'm talking about and can speak logically to my question.
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Old Jan 30, 2008 | 10:12 PM
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Originally Posted by Steven Bell
Guys, I just got an '07 Type S and have noticed when the car is de-accelerating (on it's own) and slowing down to a stop that the car "lunges" some at about 10,000 to 15,000 rpm. What do you think? Is this something that can be corrected at the dealership? What do you suggest I do? Thanks, in advance.

I hope you meant 1,000-1,500 RPM!

When the car "lunges," does that mean your car seems to accelerate or decelerate?

The TL auto trannies are supposed to downshift when they detect likely deceleratation, i.e. off throttle and coasting in gear. The TL will then downshift a gear, but it's pretty smooth on my '05 TL.

If you are on a hill, the TL transmission also has Grade Logic to keep it from shifting needlessly.
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Old Jan 30, 2008 | 10:13 PM
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i'd bet that the transmission is shifting and the ECU is rev-matching, but you are slowing down so it makes no point...
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Old Jan 30, 2008 | 10:22 PM
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Yes...I did mean 1,000 to 1,500 rpm-sorry about that. But I am slowing down when this happens-almost down to a stop. So it just seems alittle jumpy for a car of this magnitude....not as smooth as I would expect from a Type S.
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Old Jan 30, 2008 | 11:23 PM
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Originally Posted by csmeance
i'd bet that the transmission is shifting and the ECU is rev-matching, but you are slowing down so it makes no point...
ding ding ding...correct...you should like this as its very cool and sporty...an automatic that rev matches while downshifting is cool...the transmission is also making sure your car is in the correct gear so that if you need to speed up it doesnt have to down shift all the time...
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Old Jan 30, 2008 | 11:47 PM
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From: N35°03'16.75", W 080°51'0.9"
^^

Especially noticable just before coming to a stop. I just figured out what was happening a week or so ago.

It *feels* like the car momentarily shifts into neutral before the downshift; in that breif moment in "neutral", the car feels like it lunges/surges forward. It doesn't really "lunge/surge forward", it's more like the transmission/engine "unloading" and it feels lighter for a moment.
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Old Jan 31, 2008 | 02:07 AM
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Dont bitch at me for making sure you read the book before posting~ the description of your situation was not clear and in order to give good advice...
otherwise its garbage in = garbage out
Example: One member with a new TL and its fancy traction systems, went out in snow at speed, did some wild move to get across 4 lanes of freeway to take the exit and when the car though he was about to lose control it went into action with rpm limits and braking changes
Drivers responce- the TL tried to KILL ME~

Guess how many new threads per day can be answered with a look in the book?
Grade logic is discussed in my gen2 book so I have to guess its also in your gen3.
Its not in play on level normal stops- you guys need to read again
Your car is just more HP to pretty much the same failure prone trans we have, and I have a bit of personal knowledge on the subject of their failure.
Now I will stop reading gen3 trans probs- good luck to you all with Acura Corp~
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Old Jan 31, 2008 | 09:02 AM
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Steven- please look in the Garage. What you are describing is grade logic. You can also do a search on this topic as it has been discussed ad nauseum.
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Old Jan 31, 2008 | 10:16 AM
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I don't think the OP is describing "Grade Logic". I agree with csmeance and vinnier6 that's it's some form of rev matching at downshift.

If you put the car in SportShift and have it in, say 4th gear, then approach a stop but DO NOT downshift. The car, on it's own at ~10mph, will downshift all the way to 1st. I think it acts same way in full Auto.

When it does this, it "lunges" during the downshift. Happens to me frequently on flat ground. AND it preceeds the "brake assist" or "compression braking" caused by a normal downshift.
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Old Jan 31, 2008 | 10:29 AM
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in sport shift it will down shift to the next lower gear any time it thinks the speed has dropped to low for whatever gear your in....
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Old Dec 30, 2010 | 08:39 AM
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Bringing this one back!
Just have noticed my '04 doing this lunging or rpm jumping usually when cold, 30sec or 1min after warmup, when coming to a complete stop, the rpm's will jump from 1000 to like 1300rpm and then back to 1000,(while stopped) or 750-800rpm which is normal. I have read many threads discussing grade logic, and I don't believe that is what I am experiencing. If anyone could shed some light on what to look for, it would be greatly appreciated.

'04 5AT
43k
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Old Jan 1, 2011 | 09:15 AM
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mine only does this when coming down a hill while not giving any gas. like 4th to 3rd all sudden RPM shoots up from 1.1k to 1.7k and when car slows down near complete stop, becomes 1.1k again. lol

my car is 89k if anything...

Last edited by Whdrms; Jan 1, 2011 at 09:15 AM. Reason: more info
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Old Jan 1, 2011 | 09:16 AM
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Originally Posted by Slpr04UA6
Bringing this one back!
Just have noticed my '04 doing this lunging or rpm jumping usually when cold, 30sec or 1min after warmup, when coming to a complete stop, the rpm's will jump from 1000 to like 1300rpm and then back to 1000,(while stopped) or 750-800rpm which is normal. I have read many threads discussing grade logic, and I don't believe that is what I am experiencing. If anyone could shed some light on what to look for, it would be greatly appreciated.

'04 5AT
43k
wow u have really low miles on ur car.. weekend car?
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Old Jan 1, 2011 | 09:54 AM
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Originally Posted by Whdrms
mine only does this when coming down a hill while not giving any gas. like 4th to 3rd all sudden RPM shoots up from 1.1k to 1.7k and when car slows down near complete stop, becomes 1.1k again. lol

my car is 89k if anything...
This is called grade logic! Grade logic senses that you are on a downward slope, and in order to keep the car from speeding up it uses Engine Braking to help maintain your current speed. It's completely normal, an easy to way to stop it if you find it annoying is just to put the car in SS mode and leave it in 4th gear and put back into D after the hill.
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Old Jan 1, 2011 | 08:03 PM
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my 04 TL does the same thing. It always bugs me, but has done it since day 1. I bought mine new and has 75000 miles. still does it, and is still unnerving since I tend to brake firmly and it seems like the car lunges and feels as though the brakes will lock if I maintain pressure. its just an oddity I have become accustomed to....good luck.
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Old Jan 2, 2011 | 06:54 AM
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Originally Posted by Whdrms
wow u have really low miles on ur car.. weekend car?
Thanks, No it is my daily driver! Lol! I just bought it over 2 years ago with only 14k on it.
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Old Jan 23, 2011 | 07:21 AM
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Originally Posted by Steven Bell
Yes...I did mean 1,000 to 1,500 rpm-sorry about that. But I am slowing down when this happens-almost down to a stop. So it just seems alittle jumpy for a car of this magnitude....not as smooth as I would expect from a Type S.
Hi, I am a new owner of a used TL Type S (auto) w/ under 30,000 km. I noticed the same 'jerkiness' on decceleration and it has me a little freaked out but I assume it is just the 'set-up' of the vehicle, though if so, not as smooth as one would expect. I also have a '93 integra..295,000 km it has and has always had interesting shifting dynamic but keeps on ticking...hoping the TL is the same.. hope to hear other's feedback
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Old Jan 24, 2011 | 10:20 PM
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Xprt, since I posted this thread in '08, I've learned about rev matching. It's the engine-sometimes it's like driving a bucking bronco. Now, I've learned to embrace it and I don't mind it.
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