After a lot of reading, and a stumped MINI professional mechanic...

My 2009 R56/N12 with 175k miles still has a rough idle after warming up...

And, that oh so weird trait of idling normally in neutral while coasting to a stop, and only when the wheels come to a complete stop, does the idle drop a couple hundred and the car feels like it's running on 2-3 cylinders.

Runs fine going down the road.

(I feel like if someone could say why the engine idles normal til wheels come to a complete stop, this problem would be solved.)

Anyway after all my reading, VANOS gizmos seem like a probable culprit...but...my mechanic says they can't be bad unless they also throw a code.

So...

Can VANOS gizmos be bad (or need cleaned) even WITHOUT throwing a code?

Thanks...

 

Yes, VANOS solenoids can cause multiple other problems without throwing VANOS faults.

I can't tell you how many cars I've seen with either timing faults or unmetered air faults that came down to a clogged VANOS solenoid. So many, that at this point I don't begin with a smoke test, I go right to pulling VANOS solenoids.

 

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Thanks so much for that... You mentioned two kinds of other "faults"... Does that mean there were other codes? The only codes I get are

Cylinder 1 misfire
Multiple cylinder misfire
(and one more misfire code)
​​​
Plugs and coils have been checked.

So I don't get any "timing" or "unmetered air" codes...

Thanks...

 

VANOS problems can also equate to misfire issues, but before you spend the money on a new solenoid I would pull them out to confirm they are in fact dirty or clogged. Cleaning them seems to have a 50/50 success rate at staying fixed, it seems like cleaning them buys you more time, but they still inevitably fail.

 

I have the same rough idle issues on my N12 with 95K. Although I cant say its related to when wheels stop rolling.... Right now, my idle is rock steady, about 3k ago, this issue was so bad the car would stall at lights and stumble terribly. At that point, I inherited it from my wife and we bought her a new car. Since then I've been driving it and obsessed with getting to the bottom of this. This has been a very hard issue to pinpoint and I still don't know the root cause. I believe its a multitude of issues..
1) FIRST: The number one issues which seems to exacerbate this is oil level. Which is actually a very difficult thing to master given the stupid dipstick. If the oil is lower than the 1/8" below the top bulb the idle issues get far worse. But even with the oil level perfect the idle is not rock steady.
2) Ive had my Vanos sensor out Twice, cleaned them (although they look pristine) and I have to say, it seemed that both times that temporarily fixed the problem (if the oil level was also perfect). IDK, perhaps the oil level would drop, or the vanos would "drift" (for lack of better term) but the rough idle would return. Right now Im 123 miles post cleaning both vanos for the third time. My idle is rock steady. But my vanos are were so clean I cant believe this is actual culprit. (see the low cost justa maintenance plan posts)
3) 123 miles ago, I also removed my valve cover and replaced the gasket, I thought that perhaps valve cover sealing issues are more the cause of this issue. I removed and inspected the diaphragm integrated in the VC and it was in perfect condition. I also believed that perhaps carbon build up might be an issue but my head was pristine as well. There's no carbon problems on that car...

I believe there are multitude of issues that plague my idle, perhaps minute vac leaks, perhaps minor PVC issues, perhaps minor vac pump issues, or minor vanos issues, definitely oil level affects it. Perhaps minute ring and valve issues. IDK, perhaps all these components have a little wear and are not as tight as they once were, they combine and compound a problem that adds up to confusing mess to attempt to isolate and remedy. Right now, I'm so happy with this little car... its running perfect! Never thought Id be a MINI guy but Im glad the guy offended me with a low ball trade-in offer of 2k. 3k ago, my wife stalled 3 times coming home. I was so fed-up with this car, it's had perfect maintenance, and she babies it beyond belief. Yet all I've done is changed a 25 dollar valve cover gasket, cleaned and swapped the vanos, and got educated on how to really check and maintain the oil level. (which good grief...is tough)

 

PS... the only code my car threw during the stalls 3k ago were misfires on Cly #2...
Well see how long my idle remains steady, well also see if my oil consumption has reduced.
Good luck
Chris, Four Corners NM....09 Justa 95K

 

Rky...

Thanks for all that... Nice write up... I'll pass it all along to my mechanic.

Bill

 

Don't mean to ask you to do any leg work for me, but is this what I need? 2 of them? (R56/Justa/N12):


Thanks...

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Bill

 

Yes, but I've never heard of the company so quality may be a determining factor.

If they offer a decent warranty on them I might give em a try, at almost a third the cost of an OE unit.

You can try just pulling and inspecting the current solenoids and if the screens are dirty give them a cleaning with brake clean, reinstall and see what happens.

 

I've read that the VANOS can also "break"...some kind of parts inside that fail. I could sure take them out and clean them, but is there an easy way to see/know if they are broken?

Thanks...

--

Bill

 

If you haven't done any investigation yet, you can pull them out and put 12v to them, they're a simple solenoid. Provide power and ground and they should actuate, I've found that cleaning them only buys you a short amount of time.

 

More for the benefit of people looking for an answer to their hot idle misfire problem. If you have an n12 engine that is suffering from a hot idle misfire, it is likely that you have a loose inlet valve seat on the cylinder that is misfiring. Why the n12 presents the misfire while the n14 doesn't is because of the VVT technology. In the case of the n14 a loose valve seat will eventually destroyed engine while the n12 gives you a warning through a misfire at idle but if you fail to resolve it, the engine will eventually be destroyed. Through VVT the inlet valve lift at idle is very shallow and this results in the valve with the loose seat not sealing causing a loss of compression - resulting in the misfire. When you remove a cam sensor the VVT is disabled and the inlet valves move to full lift at idle and the misfire stops. So if you have a R56 that is misfiring at idle when hot, try disconnecting a cam sensor and if the misfire stops, chances are you have a loose inlet valve seat. A lot of engine specialists are aware of valve seat issues with the R56 however too few people have tagged the loose valve seat issue with the hot idle misfire. My partner has a justa that had the hot idle issue which we were able to fix, without using the parts cannon! We engaged the services of an engine specialist after a mini specialist demonstrated a total lack of understanding. By replacing a loose valve seat the justa no longer misfires. At the same time I stopped the dreaded oil consumption that plagues the R56 engines through replacing valve guide seals and scraper rings, went from 1 litre per 800 miles to no oil consumption on a 125,000 engine. We will keep the car for a couple more years and then sell on, but will not return to either the BMW or Mini brand. Gen2 engines are a disgrace and BMWs behaviour is appalling with not addressing the many issues caused by putting into production an engine that was not production ready.

 

Thank you for reply . Can you tell me how much does this repair cost ?

 

assume you do the work, I would say $1500 for parts in total, because you have to take the engine apart therefore it pays to sort out a lot of Prince engine issues so you don’t have to there again.