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Car jerks at low speed, less than 25km/h, gear2

Posted: Sun Jun 30, 2013 8:48 am
by terenceng
Dear Sirs,

I am using ASEAN RTW-P02 ECU with Flashpro.

My car just tuned by my tuner not long ago, but sometime my car likes to jerk or hesitate when rolling in 1st or 2nd gear at low speed.

Especially when I passing over a hump, press the gas enough to keep the car moving but it acts like its not getting any gas, no power and then all of a sudden jerks forward. To avoid jerky issue, most of the time i have to change the gear from 2 to 1 and accelerate the speed to more than 25km/h and then change to gear 2. It makes me look like I dont know how to drive a stick and its really making me mad.

I give it gas and it just sits there for a second and doesnt do anything and then BAM it just jerk and accels hard for a second. It runs fine when I'm at speed > 25kmh, highway cruising, high speed > 140km/h and really pushing it, has a smooth idle, and no check engine lights.

FYI, my mechanic has removed the second O2 sensor and has disable the error engine check light (should be emission check light error); My car running Rotrex C15-60 supercharger.

Anything can be done to the Flashpro?

Is it a tuning issue? or hardware issue? can it be solved by adjusting the ignition or fuel maps?

Thank you,

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Mon Jul 01, 2013 9:41 am
by Spunkster
post the calibration used as well as a datalog showing the problem.

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Sun Jul 07, 2013 8:17 am
by terenceng
Hi Spunkster,

My appreciations,

Terence Ng

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Sun Jul 07, 2013 8:18 am
by terenceng
Hi Spunkster,

Sorry for late reply as I am recently busy and outstation.

I've recently changed my rims (Forged and Light) and captured this log file at night.

The jerk issue is very minus during night time and I am not sure why..

Attached the calibration and short log file for your kindly helps.

If you need full pull log file or any other just let me know.

Thank you very much.

My appreciations,
Terence Ng

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Mon Jul 08, 2013 4:40 pm
by Spunkster
What do you mean it is very minus at night?

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Mon Jul 08, 2013 4:48 pm
by terenceng
Spunkster wrote:What do you meam it is very minus at night?

The jerk issue is not obvious at night.

I will attach another short log file to you soon.

Thank you,

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Mon Jul 08, 2013 5:30 pm
by terenceng
Perhaps i am not sure is it because of my new changed light weight forced rims.

Just for your information.

Thank you,

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Tue Jul 09, 2013 11:10 am
by Spunkster
In the fuel section of the calibratoin window, try lowering the values for the overrun fuel cut delay.

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Tue Jul 09, 2013 11:29 am
by terenceng
Spunkster wrote:In the fuel section of the calibratoin window, try lowering the values for the overrun fuel cut delay.
Hi Spunkster, thanks for your reply!

I've found the setting window, however appreciate if you could enlighten me how much of the values should I set?

The default value for stock crz asia calibration is 70 for 1-5 gears and I used it in my new DYNO tuned calibration.

Shall I adjust the value for 1 gear to 69 or lower?

Attached another log files for your reference only.

Thank you so much!

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Tue Jul 09, 2013 11:37 am
by Spunkster
Just start lowering the values by 10 or 20 and see what works best for you.

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Tue Jul 09, 2013 11:47 am
by terenceng
Thanks, will test it out accordingly.

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Thu Feb 14, 2019 11:58 am
by Gustavo424
was this issue ever fixed? im having the same problem in my car. honda civic si 2012, PRL short ram, invidia N1 catback exhaust (no downpipe). tuned on the dyno by a professional tuner, car runs perfect but has the same jerk at low speeds as described above. please HELP!!

Re: Car jerks at low speed, less than 25km/h, gear2

Posted: Thu Feb 14, 2019 12:06 pm
by Spunkster
Have you tried what was suggested above?