1.4 Vvti Engine Revs Question

[stupot]

I have been a Corolla owner for many years and have always been impressed by the quality, reliability etc.

I recently bought a new 1.4 VVTi which has a slightly unusual characteristic. When I change gear (with the engine revs at around 2 -2.5k) the engine revs rise up by around 400 rpm if the clutch remains disengaged. The revs fall to the idle speed after a second or so. Is this normal behaviour? It seems to be a waste of fuel if nothing else. Surely the engine revs should start to fall as soon as the clutch is disengaged? (My foot is off the throttle by the way).

Has anyone had a similar experience? I intend to visit the dealer but perhaps someone can add some useful insight into this?

The car is 100% in all other respects.

Any advice would be appreciated.

Thanks

[dvdmeister]

I know exactly what you mean - moved from a much older carbed car to a VVTi, and wondered the same thing. I read on this forum somewhere that the reason for it is for environmental/emissions reasons - when you dip the clutch, the engine revs up slightly before dropping down to burn off the fuel thats already in the inlet manifold. Seems to be that all the VVTi engines do it anyway, although I'm not sure that mine does it by as much as 400rpm all the time - I think the amount it revs is dependant on the engine revs you are at when you dip the clutch. The engine revs itself at least 400rpm if I'm crawling at near idle revs in low gears (1st or 2nd) in traffic and engage the clutch.

Once you get used to it, you'll barely notice it - honest :) Its just a bit annoying at first cause it forces you to change your gear changing style a bit if you come from an engine without this design 'feature'.

[Robbie335]

I also have a 1.4 VVT-i and it does the same thing. At first I didn't like it because I had to change the way I changed gear (as dvdmeister says). Once I'd got used to it though it was fine.

I've noticed that the revs only rise slightly when the engine is cold, but once it's warmed up there's just a slight delay before the revs drop.

[stupot]

Many thanks DVDMEISTER and ROBBIE335.

It seems to be a design feature then!

I did go back to the dealer, who dissappointingly, didn't say anything about it being an emission control thing. They did do some tests and said that everything was normal. The salesman seemed to think it would go away in time!

It seems to me now that it might be damping of the throttle that causes the problem. There is a slight delay before the throttle action is removed after you take your foot off the throttle. If you take your foot off the throttle and wait a second or two before dipping the clutch to change gear the engine reves do not usually rise. I dare say this is controlled by the engine management system and we are stuck with it.

I'm sure I'll get used to it. I love the car so far.

Thankyou again for your advice.