Car will not start properly when starting it! Revs are not stable, they keep coming up and down, engine is close to stop but eventually after a minute (of ups and downs) comes back to normal. If i press the throttle, the issue gets fixed instantly and the engine gets its normal revs and works properly!
All this occurs when the car is in the sun on a hot day (30-35oC temperature). Also i get a yellow half engine icon on the rev dash.
Any idea why this happens?

 

First step is to find out what code is triggering the CEL (check engine light).
Also, what year and model?

 

Νο CEL has lit. Its a 2008 R56S. And also i must say the engine oil levels are pretty low (under minimum). Could that have anything to do?

 

I would consider the 1/2 engine yellow light to be a check engine light.
(Actually, it's a reduced power engine management light).
If it just comes on when you turn the key and goes out right after you start up,
that's normal, but if it stays on, there's a problem and likely an OBDII code
that goes with it.

 

But why would it come up? Something must be wrong, its not right when the car starts, the revs to be going up n down and the engine to be very close to be shutting down!
Is it right that if i do not see a CEL there is no point in making a scan cause it simply will not show anything!

 

Without knowing the year or model, I would guess dirty mass air sensor, or maybe O2 sensor. But this is just a guess. Sounds as if a off throttle start is gulping in air and the ECM is not happy with it, but it might as well be from the exhaust side. And as the throttle is hit and the air flow increases then it settles in correctly. (Exhaust would be increased heat burning off residue)

But again, only a guess.

Please keep us posted on what you find.

 

Some CELs are stored in memory for a while. It worth getting it scanned. Also not a readers will be correctly read the Mini specific codes.

 

My mini is a 2008 R56S and i have 2 more things to add.
1. i just realized that environmental temperature has nothing to do with it (early in the morning that temp is low the issue still occurred)
2. i can smell petrol -outside the cabin- when the issue occurs

 

These are all guesses here. but check and see if there are codes stored. And also make sure all your fluids are full. Never run the engine oil level below minimum. .

 

Your first order of business is see if there are any codes stored into the ECU, some particular codes can only be read by Mini. So at the very least check for stored codes because we can guess all your want and still get nowhere.

 

There may be codes stored that don't cause a CEL. I agree with previous contention that it could be a MAF etc, but something else to think about. The HPFP's in these are inherently defective. Certain stages may be lower pressure than they should be. Have you had yours replaced. This fixed a similar issue with my car. Only difference is that it was the first stage in mine that was defective manifesting itself on first start after a few hours. If it is this you will see cylinder misfires, perhaps on cyl 3.