"Jerky" coasting problem

T

tacthecat

Well-Known Member
212
80
Cheshire, MA - USA
Vehicle Model
2012 Si
Body Style
Sedan
Well, now that we've got the Rev Hang fixed, we've noticed our Si Sedan doesn't like to coast going down longer downhills, even slight ones, at Highway speeds 55+ +++. It holds the speed where it's set but it's "jerky".
 
I have made this a new thread and will post this link in the "thread challenge" thread :wavey:
 
webby said:
6th gear,..5th gear? Does it matter?
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Only sure of 6th, use lower gear only when desending "steep" grades and speed is increasing too much for the speed control to react.
PS - Love the cruise control re-engaging up- or down-shifting.
 
are you referring to the car jerking with cruise control on?
 
webby said:
are you referring to the car jerking with cruise control on?
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Yes, the cruise control is very steady and pleasant except on long downhills where the transition from power on/off is similiar to someone tapping (very lightly) a tune with the right foot on the gas pedal.
It's like the engine is "hunting" for the right amount of power to apply but is over aggresive with the transitions.
 
This has also been an issue on the 8ths. According to Vitaly (of E-Tunez), Hondata has recently allowed the adjustment of an ECU variable (I'm unclear as to WHAT variable exactly) that he's personally seen resolve this issue on many of the cars he's tuned.

Contact 'VitViper' for more info. Though, we probably won't know if said variable has carried over to the 9th gen at this point - but once FlashPro is released for you guys, you should be able to determine this.
 
PainIs4ThaWeak said:
This has also been an issue on the 8ths. According to Vitaly (of E-Tunez), Hondata has recently allowed the adjustment of an ECU variable (I'm unclear as to WHAT variable exactly) that he's personally seen resolve this issue on many of the cars he's tuned.

Contact 'VitViper' for more info. Though, we probably won't know if said variable has carried over to the 9th gen at this point - but once FlashPro is released for you guys, you should be able to determine this.
Click to expand...

Thanks, I'll keep this in mind. Interesting that the only related post I've seen for the 9ths was part-throttle jerkiness (my words) AFTER the Hondata ECU Re-flash.
 
tacthecat said:
Thanks, I'll keep this in mind. Interesting that the only related post I've seen for the 9ths was part-throttle jerkiness (my words) AFTER the Hondata ECU Re-flash.
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he's talking about the hondata flashpro though, which allows for custom tunes. The hondata reflash is a single tune that cannot be altered.
 
My car's build date is 3/12 and I have not had any dealer reflash....yet, so i assume my car has the early pre-update software. (when I have time I'll go for it to reduce the rev hang.)

Getting back to my point though, my car has always done this when cruise control is on. Especially after cresting a long highway uphill. I find it only a slight irritation. When I noticed it I just shrugged my shoulders and said, "Well, it's not a Mercedes or anything."
 
2000GM said:
My car's build date is 3/12 and I have not had any dealer reflash....yet, so i assume my car has the early pre-update software. (when I have time I'll go for it to reduce the rev hang.)

Getting back to my point though, my car has always done this when cruise control is on. Especially after cresting a long highway uphill. I find it only a slight irritation. When I noticed it I just shrugged my shoulders and said, "Well, it's not a Mercedes or anything."
Click to expand...

Agree it's minor - just wanted to make sure it wasn't my imagination. And, now that we've got Rev Hang under control, there aren't any other issues - purrrr!
 
I noticed the same thing going down long hills as well as the rev hang. Guess I will be stopping at the dealer sometime soon.
 
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