Team-BHP - i10 1.2: RPM goes up when clutch is pressed. Normal?

Hi All,

We have this i10 Kappa (1.2), which is less than a month old and I've noticed something strange with it:

At slow speeds, when I press the clutch (and of-course release the accelerator), the RPM shoots up for about 2 seconds and then settles down. This is observable when the car is being parked (as road noise is practically absent in the basement car park). Is this normal?

I talked to Trident Hyundai guys and they claimed that this happens with all the cars, especially when they are being reversed. I am not inclined to trust that, hence this question.

Thanks,
Su-47

Quote:

Originally Posted by Su-47 (Post 951717)

Oh, so it happens in the i10 Kappa too ? I've been experiencing the same problem/behaviour/phenomenon on the Santro Xing (pre-eRLX) for nearly 3 years now.
Seems to some (strange) ECU programming on Hyundai cars which shoots up the RPM on pressing the clutch.
I've not experienced this on any other car brand though

Can anyone else confirm this behaviour

Quote:

Originally Posted by jav (Post 951782)

test drive another i10 and see if the rpm goes up

Thought of doing that, but, when I went to the workshop, the testdrive car had gone out. Will do some other time..

Quote:

Originally Posted by for_cars1 (Post 951754)

Oh, so it happens in the i10 Kappa too ? I've been experiencing the same problem/behaviour/phenomenon on the Santro Xing (pre-eRLX) for nearly 3 years now.

I will try it on another i10 again, when I get the time. Will keep you posted...

This is bound to happen under the circumstances you cited. Very simply when the clutch is engaged the engine in under load and the rpm is bound to be lower than when disengaged, the moment you disengage the clutch the ecu will take some time to alter the amount of charge going in to the cylinders and hence to spike. The drop back to normal levels is an indication that the correct charge at idle is being allowed into the cylinders, all happens in a fraction an is nothing to worry about.

Quote:

Originally Posted by Su-47 (Post 952099)

Howler,

If it happens in a fraction of a sec, I shouldn't be able to notice it. I think it takes about 1-2 secs to happen. Is that also normal?

Cheers,
Su-47

oh ok, not too sure about it now, i guess the best bet would be to drive other kappas, it could be characteristic to the car, but it sounds like a lag in the response time of the ecu,i maybe wrong too, experts;your comments please?

Hi there

I have exactly the same problem with my brand new Santro, trust me i have banged every door of Hyundai Service Centres but till date nobody able to tackle the problem. This fluctation of RPM occurs mostly in B2B traffic. Just trying to live with me.

From the service advisors i have got all sorts of explanation, but one answer was a bit reasonable. He said that the ECU is of 8 BIT ( low capacity)

Amit

I have an SX4 and the same happens there!! When asked about it, one of the service guys mentioned that it would reduce after running about 10,000 km! The rpm shoots up by about 500 rpm and then slowly settles down. Have decided to wait and watch!

Quote:

Originally Posted by nma83 (Post 952202)

I have a Getz 1.1 and exactly the same things happens to me too. Looks like a characteristic of Hyundai ECUs!

Hi

This is because both the cars share the same engine. I still fail to understand why the service advisors don't have a clue about this problem is Hyundai Service stations.

Amit

I second what howler says.

This is a basic phenomenon for all engines.
There is a certain load for the engine at say 1000 rpm. when you disengage the clutch, you have removed all load for the engine, and with the reduced load the throttle ( fuel rack) has to reduce as well to maintain that 1000 rpm. The time taken to effect that change will depend on the programming of the throttle control software, amongst other factors, and in that period the rpm will increase before stabilising at its original rpm.

I have noticed this in UVA, but this happens only at the start of the day or engine is cold.

The typical cycle is

At cold - Start - RPM - 1100
Engage 1st Gear - Rpm increases and drops to 1000
Press clutch and engage 2nd - for a moment the RPM shoots up and settles down to 1000.

Suddenly if I have to stop and I press clutch and disengage, on pressing clutch, RPM shoots up to 1300 or so and settles down now to 1000.

Eventually after a 0.5 KM or so all becomes normal and On depressing clutch The RPM settles at 800, which is normal operating RPM.

I think, the theory might be (I am no tech guy in this, just trying to apply logic) the engine runs rich at start and we try to reduce the RPM by not accelerating or by using the rich mixture to move ahead. The moment we disengage (press Clutch), the engine goes back to rich mode at idle (which is seen at start). Thus RPM shoots up.

The engine later runs lean gradually and all works at normal at 800 rpm.

The strange thing is I have never noticed this behaviorin MY Palio 1.6.