Hey guys, first post woo!

We have just bought a sweet silver 2009 E60 523se (UK) and loving it, completely pristine inside and out; even though it's on 109k miles it's clearly been looked after meticulously. The only thing is, it's missing when I jab my foot on the throttle. Not just on the road (at launch or sudden heavy acceleration) but stationary/neutral also.

First few seconds from cold is a little lumpy too. No faults showing, but wants to stall if you ride the clutch in 1st on a slight incline, in fact super chuggy up a steep hill in 1st. What gives? Feels like it might be coil or spark related. Any easy things to rule out without shelling our for a reader?

Any help appreciated. Can get so far, as I've always had a go at my cars but I'm more used to E36s, Vauxhall Omegas, Astras and VW T4s cheers.

 

I'd shell out for a BMW code reader. You can find them as low as $44.99 (US).

 

So there's literally nothing to check before shelling out for a code reader... Like I specifically am trying not to - I just throw money at it? Like no vac pipes you can recommend checking or common stuff?
BTW I read the so you've just bought.. guide. The code reader in there doesn't exist, it says 502 not 520, has a typo.

 

You can try checking for a vacuum leak. If it were the plugs or coil packs, it would throw a code.

 

Common stuff would be performing a smoke test if you think it has a vacuum leak, performing maintenance (plugs) if you know it's needed or using a fuel system cleaner. Honestly if it's not throwing a CEL you'll be going crazy trying to figure it out. Personally I would be trying to look at live data. INPA, ISTA or a decent OBD2 reader. If you have neither then you're wasting your time. BMWs can't be figured out without software or a reader because what's common to some isn't common to others with the same symptoms which in turn will have you throwing parts at an issue wasting money.

 

It could be a lot of things, I'd suggest investing on diagnostics equipment as well. INPA is a great tool for diagnosing this things.
My experience and main culprit with this problem was the CCV valve. In my engine (N53) it was part of the head cover, and ended up having to replace it entirely, although you can buy kits to repair it. I broke it on the process tho

In the case of the N53 you can test this theory by plugging the CCV vent hole with your finger, and seeing if the idle stabilises after that. Smoke machine will not help you with this, as the smoke will not pass through this valve.


I don't know how to check it on other engines. I know that the N52 has the CCV under the intake, but it's harder to check there. Maybe a smoke machine will work on that.

Other issues could be clogged VANOS solenoids, vacuum leaks, broken DISA valves, sparkplugs, coils, MAF... Very long etc. Best thing is to invest in good diagnostic tools, will pay themselves on the long run. I've payed my lapton 2 times with 3 issues I found with it.