[the_skyliner]

We have a WagonR which was purchased last year and has clocked 3k on the odo. So far there have been two issues with the car and both related to GB.

In just two months of ownership, the orange colour lamp came up suggesting we need to check the AMT. Car was sent to the service station and they did something and the lamp went away.

Recently, I noticed juddering at times on inclines and at 10-15kmph speeds. Saw this thread and realised that there are others facing the same issue.

Will talk to service station guys to find a solution when next time there.

Adding my name to the list:

The list of members facing the juddering issue stands as:
1) audioholic - Bangalore
2) sparky - Rajkot
3) hillsnrains - Bangalore
4) prasanna_indaje - Bangalore
5) joe-Ker - Chennai
6) jomson13 - Pune
7) the_skyliner - Pune

[giri1.8]

Originally Posted by audioholic

Irrespective of whether you press accelerator or let go of it, the AMT unit instructs ECU to cut the throttle input during the gearshift and once the shift is done, throttle inputs are back to how the accelerator is pressed. This is what causes the momentary lag at some gears and speeds.

So does that mean I can shift gears in manual mode, without lifting my foot completely off the accelerator ?

Just wish to know the logic behind the shift, and might be useful in certain situations !

[audioholic]

Originally Posted by giri1.8

So does that mean I can shift gears in manual mode, without lifting my foot completely off the accelerator ?

Just wish to know the logic behind the shift, and might be useful in certain situations !

Definitely you can shift. It is not like in a manual transmission where if you keep the accelerator pressed it will result in the engine revving high. Since this car is driven by wire, the accelerator pedal is just an electronic input device. The actual throttle control lies with the ECU. This will allow it to cut throttle during a gearshift, irrespective of whether you are in the manual mode or auto. The AMT module and ECU communicate with each other and manage the shifting. The throttle cut also allows revv matching in the lower gears.



The gearshifts are triggered by a large number of parameters, starting from something as simple as the vehicle speed, RPM all the way till the incline, etc. There are maps to determine which is the best gear for a given condition and that is selected. Out of the many inputs, driver behaviour is also one. The maps are altered over a period of time based on driver behavior. Hence, this will lead to the shift points differing from car to car based on the driver. There is no fixed logic to decide which gear is to be chosen.

[bhp_maniac]

Originally Posted by audioholic

In my car, the shift points have changed well. 1-2 happens at 20kmph, 2-3 at 40, 3-4 at around 50-55 and 4-5 happens at 70 with a light foot and 90 with medium throttle. I rarely face an issue of early upshift now.

This is pretty much what I want, may be we can swap cars Jokes apart, I will try it out this weekend and see if I can tame the kid

[xjosephjacob]

Originally Posted by audioholic

Since this car is driven by wire, the accelerator pedal is just an electronic input device. The actual throttle control lies with the ECU. This will allow it to cut throttle during a gearshift, irrespective of whether you are in the manual mode or auto.

Interesting, and thanks ! How is it that the shift-shocks are greatly reduced when we leave the accelerator pedal at the gear shift points ? I recently drove Swift AMT in manual mode, leaving the accelerator pedal whenever execute a gear shift, and found the shift action to be incredibly smooth. In-fact gear-shifts were much quicker than I expected and I found the AMT reasonably fun to drive as well.

[audioholic]

Originally Posted by xjosephjacob

Interesting, and thanks ! How is it that the shift-shocks are greatly reduced when we leave the accelerator pedal at the gear shift points ?I recently drove Swift AMT in manual mode, leaving the accelerator pedal whenever execute a gear shift, and found the shift action

Thats because if you let go of the throttle yourself, the engine can slow down naturally instead of the ECU having to do the same forcibly by cutting throttle abruptly on your behalf. This gives the transmission more time to shift or rather seize the opportunity. By letting go of the throttle and pressing it once the gearshift is done, you will be imitating the same behaviour of a manual transmission car whereas if you keep accelerating, the ECU will forcibly cut throttle, and after the shift it will immediately open throttle back to the original position. This causes the shocks, which is similar to releasing and pressing the accelerator again quickly.

[Sparky]

Just correcting the list of members facing the issue, 7th entry was done twice. Hope somebody from Maruti is watching this list..

The list of team-bhp members facing the juddering issue in Maurti AMT stands as:
1) audioholic - Bangalore
2) sparky - Rajkot
3) hillsnrains - Bangalore
4) prasanna_indaje - Bangalore
5) joe-Ker - Chennai
6) jomson13 - Pune
7) ajayclicks- Bangalore
8) the_skyliner - Pune

[Leoshashi]

A close friend's Alto K10 AMT, which had done 22000kms started juddering. It's clutch was replaced under warranty at around 20,000kms, but it started juddering again. After a long diagnosis at my MASS, the mechanic changed two gaskets: Throttle body and intake manifold and the issue stands resolved. It was noticed that the RPM was fluctuating badly whenever it was juddering. They tried cleaning the IAC and TB, but it didn't help. Eventually the issue was traced down to these gaskets. He has driven more than 2000 kms post the gasket change and there has been no juddering or vibration of any kind.



Regards,
Shashi

[Sparky]

Originally Posted by Leoshashi

A close friend's Alto K10 AMT, which had done 22000kms started juddering. It's clutch was replaced under warranty at around 20,000kms, but it started juddering again. After a long diagnosis at my MASS, the mechanic changed two gaskets: Throttle body and intake manifold and the issue stands resolved. It was noticed that the RPM was fluctuating badly whenever it was juddering. They tried cleaning the IAC and TB, but it didn't help. Eventually the issue was traced down to these gaskets. He has driven more than 2000 kms post the gasket change and there has been no juddering or vibration of any kind.

Thank you for info. In my celerio, they changed the complete throttle body, flywheel and clutch set. Its been about 1500 km post parts replacement, the regular juddering is gone. However, the car does judder rarely, like once or twice in a month, mostly during take off.

[Leoshashi]

Originally Posted by Sparky

Thank you for info. In my celerio, they changed the complete throttle body, flywheel and clutch set. Its been about 1500 km post parts replacement, the regular juddering is gone. However, the car does judder rarely, like once or twice in a month, mostly during take off.

In my friend's car too they replaced the throttle body for checking, but since it didn't make any difference after the gasket change, they installed the old TB back.

Regards,
Shashi

[audioholic]

Originally Posted by Leoshashi

In my friend's car too they replaced the throttle body for checking, but since it didn't make any difference after the gasket change, they installed the old TB back.

Regards,
Shashi

Have placed an order for TB gasket. There can be two things happening with the AMT. One is jerkiness and the other judder. In my car, there is no RPM fluctuation to cause jerkiness. However there is judder. But since this solution looks too simple and the gasket is hardly any money, I will give it a shot

[Leoshashi]

Originally Posted by audioholic

Have placed an order for TB gasket. There can be two things happening with the AMT. One is jerkiness and the other judder. In my car, there is no RPM fluctuation to cause jerkiness. However there is judder. But since this solution looks too simple and the gasket is hardly any money, I will give it a shot

As you can see, they had changed some intake manifold gasket too. Kindly check if your car needs that too.

[hailstorm]

I have a 3 year old Celerio AMT with 38k on the odometer. The AMT used to shift to N whenever the car had to downshift. Eg Overtaking, or driving uphill when the car is cruising in 4th/5th gear. Surprisingly, this used to happen only when the speed is around 60kmph with rpm hovering around the 2000 mark.

Got the AMT recalibrated twice from different workshops but the issue was not solved. Finally told the dealership to resolve the issue else I would drag them and MSIL to the consumer forum.

Finally got my car back after a month!! To the credit of the service advisor, he was constantly in touch over phone and used to brief me on the developments every 2-3 days. It seems they have changed each & every component of the gear box. I was charged just for the clutch plate which needs to be changed at 40k kms, as per the Service advisor.

Haven't been able to drive on highway since, and it looks ok in city drives apparently. Keeping fingers crossed that the issue wont crop up again.

On the delay, what I heard from the dealer is that the approval for replacement of parts, and guidance on future course of action and tests from MSIL officials took too much time.

And I was charged 1300/- as fuel cost for driving my car for about 50 kms for trails.

Its nearly a week since i Took delivery but havent received any calls from MSIL (Dealership had called for service feedback) to check if I am satisfied from my car now. So much about the excellent service back up from MSIL.

[Sparky]

Originally Posted by audioholic

Have placed an order for TB gasket. There can be two things happening with the AMT. One is jerkiness and the other judder. In my car, there is no RPM fluctuation to cause jerkiness. However there is judder. But since this solution looks too simple and the gasket is hardly any money, I will give it a shot

Hello Audioholic, did you tried replacing the gaskets? Let us know if any update.

[audioholic]

Originally Posted by Sparky

Hello Audioholic, did you tried replacing the gaskets? Let us know if any update.

Nope. I have purchased them sometime back, but didn't get time to work on the car since either since it's used continuously these days either by me or dad. Will do the replacement sometime this week. Moreover, I was also thinking of sending my car for another clutch replacement since after 13k kms on this set its slowly developing judder. The same makes me believe that my issue has not got much to do with the throttle body. Since it wasnt an expensive thing, I am interested to give a try.