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Greg
Greg, Technician
Category: Vauxhall
Satisfied Customers: 7114
Experience:  Automotive diagnostic tech
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Vauxhall Corsa 1.2 Excite 2011, 9,000 milesOn changing gear

Customer Question

Vauxhall Corsa 1.2 Excite 2011, 9,000 miles On changing gear engine rpm increases as clutch is depressed and engine comes off load before falling back as one would expect. Seems particularly noticeable from 1st to second and second to third gear. Car otherwise faultless and driven with care. John XXXXXXX

Submitted: 3 years ago.
Category: Vauxhall
Expert:  vauxdoc replied 3 years ago.
Welcome to Just answer, This behaviour is often queeried by customers but is in fact quite a normal "characteristic" on over run.

The engine management system holds the revs up on over run to protect the thermal overload of the catalytic convertor, Vauxhall brought a bulltin out a couple of years ago advising of this.

I know where you are coming from with your observation, older management systems systems and carburettor engines used to shut off to idle, if you where to test drive an identical Corsa it would be exactly the same.

I hope this helps, best regards, Vauxdoc.





Customer: replied 3 years ago.

ear Vauxdoc
Thanks for your reply. However it's not helpful. The car has only just started to exhibit the problem I described. No other car I have ever driven, including other Vauxhalls, has ever increased the engine rpm on changing gear. Modern cars, using an electronic throttle, do not shut of the throttle as quickly as older cars in order to control the overrun as part of the pollution control process. That said, I've never experienced engine rpm actually increasing as the engine comes off load when you change gear.
John

Customer: replied 3 years ago.

Dear Vauxdoc


How can you claim this is a normal response? Stand by any road and listen to a car accelerating away - do you notice that the engine rpm rise even higher at the point of changing gear? You do not.


There is clearly a delay in the ecu shutting the throttle which momentarily causes the engine rpm to rise as you depress the clutch. This is obviously not normal. The ecu controls the rate at which the throttle closes but point at which that starts is the very moment you take your foot off the accelerator; not after you've depressed the clutch.

Expert:  Shantal-Mod replied 3 years ago.
Hello,

I've been working hard to find another Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.

I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you.

Thank you,

Shantal
Expert:  Greg replied 3 years ago.
Hi .

Is the check engine light "ON" when the engine is running .or any other warning lights .

Was any work done before you had this problem.

When was the last servive done .

Will you be doing the bwork on this car .

Rgds Greg