Revs creeping

Shoza

Shoza

Shoza

Associate
Joined
5 Jan 2011
Posts
724
Not sure if this is a problem which is obvious or could be leading to something that will be a bigger problem. My wife's 1.3CDTI Corsa has started creeping on the revs in idle. It will sit there around 900 and hover up to 1100 every few seconds and therefore sounds like it is humming up and down. Faulty ECU maybe? Heard these can get wet because of the placement on a Corsa - is that correct?

Car otherwise fine under power with no obvious issues with the car - serviced (filters, sparks & oil replaced) and MOT passed a few months ago.

Thank you
 
I had this after changing the oil on the Civic. I had knocked a vacuum pipe off the intake manifold when reaching over to take off the oil filter.
 
When was it last serviced?

I doubt its a faulty ECU.

If it hasn't been serviced for a while it could be Spark plugs, coil packs/leads/ignitor/etc.
But, I'd put money on it being a faulty EGR valve.
 
Matt-Page said:
When was it last serviced?

I doubt its a faulty ECU.

If it hasn't been serviced for a while it could be Spark plugs, coil packs/leads/ignitor/etc.
But, I'd put money on it being a faulty EGR valve.
Click to expand...

It'd struggle to be spark plugs as it's a diesel :p

My money is on some sensor somewhere, it'd be worth reading the ECU to see if it's storing any codes.
 
No it happens with nothing running in the car.

I also don't think it's an air leak as I thought that would have affected MPG which has remained exactly the same for some time now (average 60mpg) and there is no obvious performance loss either?
 
It's likely an air leak past the throttle body on the vacuum side or the idle control valve sticking. I have had similar issues with my mondeo recently.
 
Its a diesel.

The only way that the revs are going to "creep" is if extra "Fuel" is being introduced to the engine.

It is either an engine management issue or it is, occasionally, eating its own oil.

This needs urgent investigation. Though it doesn't sound like an oil issue from the description, oil issues need to be eliminated since if an oil issue goes bad the engine will explode (Literally, Check Youtube for "diesel runaway"! :eek:)
 
Is it a common rail?

If so it's likely either the injectors need a leak back test or the pressure (suction) control valve need looking at.

Highly doubt it's the EGR valve.
 
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