Idle does not drop fast enough

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Old Jan 5, 2006 | 07:39 PM
  #1  
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Idle does not drop fast enough

I have a new 6MT, and was wondering why my shifting seemed so erratic. I now the TL's are "touchy" to learn, but it seemed abnormal.

I started watching the tach, and noticed the engine RPM does not slow down fast enough for the next gear. When the clutch engages, you can shake the car. If you touch the brake though, the RPM drops like a rock.

Does anyone else notice this. If I shift slower (as has been brought up before) this does not seem to be as uncomfortable. But I have never seen an engine that likes to stay at a high idle so long between shifts.

Any thoughts?

Mark
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Old Jan 5, 2006 | 08:21 PM
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I have to agree. Mine does the same thing and I just broke 2,000 miles. I know the emissions is related but I am not sure.
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Old Jan 5, 2006 | 08:33 PM
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Part of it is the fact it drives by wire and not cable....
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Old Jan 6, 2006 | 11:06 AM
  #4  
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It IS due to emissions. Our engine is classed ULEV. The reason the RPMs sometimes drop more slowly than you expect is because this allows the engine to burn off any fuel that could be puddling in the intake manifold.

My '04 TL is fine in this regard. Granted, it doesn't drop off like an engine of maybe 30-40 years ago (or even, in some cases, 10 years), but it has not caused me any problems.
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Old Jan 13, 2006 | 08:45 PM
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I have definitely noticed this too, and I hate waiting for the revs to stabilize before engaging the clutch. (But, isn't it TOTALLY cool that the TL does this - can figure out the RPM needed for smooth engagement for the next upshift. Does any other car do that?)

My current shifting technique is basically I let up on the gas and push in the clutch at the EXACT SAME TIME, and I get the slow RPM stabilization.

I've been experimenting with a new technique to try to get the engine RPM to drop faster. I don't have definitive results, yet, but I'll post them, if valid. My current experiment, is that I let up on the gas just a split second before pushing in the clutch. This seems to cause the RPM to drop quicker, and I can shift and engage with no waiting. My guess is that the combination of early gas release and clutch push signals the computer a bit more clearly what I am about to do (i.e. upshift), and it reacts faster? I don't know.

I've also noticed that when the engine is cold, the RPM drops like a stone on upshift, no matter what.
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Old Jan 13, 2006 | 11:09 PM
  #6  
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i've also noticed some variation between speed in which the rpm's drop but have not paid enough attention to the different factors which might contribute to that.
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Old Jan 13, 2006 | 11:43 PM
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It's the one thing that freaking bugs me to no end when I'm driving my brother's car. The shifts get really jerky, and he calls me a bad driver. I'm fine when I'm driving my friends' cars, including but not limited to, an S2000, Type-R's, Miata, etc... all modified. But he's much smoother with it than I am, so I guess you just have to get used to it.

On a side note, I realize Honda has always been the one to combine engineering and environment together. But when environmental factors interrupt driving dynamics and pleasure... I say to hell with it. I'll be happy with LEV instead of ULEV if it meant the car was more pleasurable and easier to drive.
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Old Jan 16, 2006 | 01:05 PM
  #8  
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I think it is caused by VTEC

I'm not a mechanic, but I believe this is caused by the VTEC technology. When you're at high RPMs, the high RPM/high horsepower cam profile is being used. When the clutch is stepped in, your RPMs drop to about 2k (which must be where this cam profile idles at), then the engine switches over to the low RPM/high torque cam profile and your idle drops to the standard 1k.

Again, I'm not a mechanic. This is just my theory on it.
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Old Jan 16, 2006 | 08:31 PM
  #9  
ndx2's Avatar
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Originally Posted by Pure Adrenaline
It's the one thing that freaking bugs me to no end when I'm driving my brother's car. The shifts get really jerky, and he calls me a bad driver. I'm fine when I'm driving my friends' cars, including but not limited to, an S2000, Type-R's, Miata, etc... all modified. But he's much smoother with it than I am, so I guess you just have to get used to it.

On a side note, I realize Honda has always been the one to combine engineering and environment together. But when environmental factors interrupt driving dynamics and pleasure... I say to hell with it. I'll be happy with LEV instead of ULEV if it meant the car was more pleasurable and easier to drive.
1. You are a "bad" driver. Good driving skills, but you drive like a bad-ass.
2. Good driver would quickly get used to the car, and not expect the car to be the same as other cars.
3. Once you get used to the computer rev matching for you, it's not that annoying.

1st to 2nd does get a while to get used to, for most people anyway... it'll be a jerky ride for some time.

I'm not 100% positive, but I think the rev drops quicker if the RPM is below 3k or 2.5k or somewhere around there.
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Old Jan 17, 2006 | 08:34 PM
  #10  
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you'll get used to it.

it's caused by a very lean mixture (ulev). you'll notice it's almost normal @ cold engine temps because the computer dumps more fuel into a cold engine (fuel enrichment has an effect similar to the "choke" on your lawnmower; it creates a richer mixture).
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