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Originally Posted by reinhardt93 We realized that the gearbox would still be in second gear and would never go into first while coming to a stop. After he stepped on the accelerator, the car would accelerate slowly (or with a delay as you mentioned) and then the gearbox would shift down in a hurry with a slight clunking noise to the first gear to pick up speed.
We just decided to live with it and considered it to be a little quirk of an otherwise amazing vehicle.
I am guessing that this could be the issue you are facing and maybe you could try putting it in manual mode and seeing if it does something similar. |
The same thought crossed my mind as well. I think that the car is staying in the second gear when I come to a stop. As soon as I accelerate again, the gearbox is realising that it needs a lower ratio gear for better pickup and it’s shifting to the first gear. Maybe that’s what is causing the jerk/pause and the drop in the RPM as well.
Unfortunately, I can't check out this theory as the Sonet doesn’t display which gear is engaged. It just shows ‘D’ on the screen while driving (in all the driving modes). I can see the gear that has been engaged only in manual mode. However, if I test this theory in manual mode, it won't be of any use. The car will most probably stay in the gear that I have engaged manually. In the end, I won’t know what the ECU and gearbox are doing in the automatic mode.
That being said, I will still try out this theory in manual mode and see if I discover anything. Thank you very much for your input.
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Originally Posted by Mortis I think maybe you are stepping on the gas too soon and this is happening because of the difference between petrol and diesel and possibly because of the gearbox tuning. |
Actually, yes, I am stepping on the accelerator pedal very quickly. I don't like there to be a long gap between my car and the car in the front when the traffic starts moving because then the two-wheelers try to get in between. So, as soon as the car in front of me moves forward, I immediately shift to 'D', lift my foot from the brake pedal, and press the accelerator pedal. When I don't press the accelerator pedal immediately, I don't feel the jerk/pause as much as I do when I press the accelerator immediately.I do the same thing in my Volkswagen Vento DSG as well but I don't experience any jerk at all.
Anyway, after driving my Sonet for almost 1,500KMs and taking test drives of two other Kia Sonet Diesel Automatic cars as well as the Kia Seltos Diesel Automatic, I have also come to the same conclusion as you. This is just how the engine and gearbox are tuned. I am sure about is that there is no issue with my vehicle in particular. If this is an issue indeed then it is with every car with this engine and gearbox combo. If this issue needs to be solved, Kia has to offer a software update to all the cars.
That being said, I will still check out all the theories that people have been suggesting to me on this forum. Maybe I will discover something new. Thanks for your input buddy.
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Originally Posted by CarWorld My 2 cents here with another angle. In Sonet diesel automatic, hill hold assist feature becomes active in auto mode especially on inclines for 2 - 3 seconds after lifting your foot from brake pedal. I have test driven Sonet diesel on inclines and experienced this. I have seen the same behaviour on Honda City ZX CVT too where the sales guy specifically asked me to lift foot from brake and asked not to accelerate till car starts rolling back just to test hill hold feature. Same should be the case for Seltos diesel automatic too. Hope this helps. |
That thought crossed my mind as well. Maybe the whole process of the Hill-Hold Assist feature where the brakes are engaged till the accelerator pedal is pressed is causing the jerk/pause. Here's my theory:
The brakes are kept engaged by the Hill Hold Assist feature for a short period of time even after pressing the accelerator pedal (to avoid rollback). So, when the car can't move forward for that short period of time when the brakes are engaged, the ECU increases the engine RPM in order for the car to move forward. When the Hill-Hold Assist feature releases the brake, the car suddenly moves forward and the ECU realises it doesn't need so much power. So, it drops the engine RPM.
This could also be the reason why the jerk/pause is much more noticeable when I press the accelerator pedal immediately after lifting my foot from the brake pedal. Well, I will check out this theory too as soon as possible. Thank you very much for your input. I will keep you all updated if anything changes.