Hello,
I'm experiencing Rough idle when WARM and 2 fault codes: p0171 and p0174.
Has anyone experience this problem on N53 engine? I can't find any videos or chat about N53.
I have 170 000 km.
The weird thing is that it's not regular. Cold engine starts with no problems. When it gets warmer or if the outside t is high, rough idle starts.
With warm engine if I stop at red light, rough idle starts only at about 70%. Sometimes nothing happens. When I press gas pedal it disappears.
I'm not experiencing power loss and rpm doesn't jump when driving.
I kinda seems as a sensor fault, but then again why only when warm?
I've checked for vacuum leaks with home metod, but didn't find anything. All hoses and plastic looks as brand new.
I researched that maybe it could be: ICV or DISA. But I can't find ICV-Idle Control Valve and DISA valve in the engine. also no codes for that.
Can this be an oxygen sensor fault?
I also cleaned MAF. Can MAF be the problem?
PROBLEM FINALLY SOLVED..
It was CVV diaphragm. Service said that I should change the valve cover for 460eur, because they have tried to change only CVV but always failed.
I tried to change only the CVV myself and success. It took me 4 hours thou, but costed 30eur only.
With the wrong tools changing it is almost imposible.
Last edited by UOskars; 06-12-2018 at 01:51 AM. Reason: SOLVED
We don't have the N53 in the US, but I'm assuming its a variant of the N52? If that's the case, it does not have an idle control valve. Idle speed is controlled by the valvetronic system. Just an FYI. Sorry, I can't be more help to your problem. A good start would be reading the codes with an actual BMW scanner, not generic P codes.
ASE and BMW Master Certified Technician
N53 is essentially an N54 w/o turbos.....NA, DI, no valvetronic, MAF instead of MAP.
P0171 & P0174 are lean codes. DME is adding more fuel to compensate.
Likely causes are air bypassing MAF due to leaks in intake boot, CVV diaphragm in valve cover or CVV hose to intake manifold.
PROBLEM FINALLY SOLVED..
It was CVV diaphragm. Service said that I should change the valve cover for 460eur, because they have tried to change only CVV but always failed.
I tried to change only the CVV myself and success. It took me 4 hours thou, but costed 30eur only.
With the wrong tools changing it is almost imposible.
Congratulations on the repair and thanks for the followup.
Can you tell us where you got the diaphragm? Post a link if you have one.
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