Hi All,

I finally gave in and i'm asking for help from anyone who has more experience with these n14 motors. I attached a video of my test drive. The audio is terrible but you can turn it up a bit and watch the needle to sort of figure out whats going on. Its much worse in person when your driving and in the car.

The video is pretty large so i'll try to describe it in words here in case i cant get my video to load or if you just don't want to watch a 2 minute video of a surging engine.

What its doing is basically bucking like a horse whenever i get to a stop sign. Sometimes it will surge up and down so bad that the engine shuts off. It also surges and idles roughly when its in park but i just took it on a drive so i could document it really bad on video. The weird thing is that it only does this when the engine is cold. eventually after it warms up, after about 60-70 degrees it stops and i can drive the car like normal but even then, i still notice a very delayed and abnormal throttle response. im not getting any codes except the occasional misfire # 1-4 but that's obvious since the engine shut down. this car is a 2009 mcs automatic tranny.

Im going to give you a little bit of background of myself so you have an idea who is working on the car and why i have mind boggling on the title.
Im pretty decent at wrenching, and i have bought and sold about 8 of these cooper s recently. All have had engine issues like timing chains and running without oil or something. Ive pulled the engine on some, did the timing chain on others, so im pretty fluent under the hood of an r56. i have a standard Launch Creader v7+ scan tool i use to pull codes. i have a "fleet" of know good parts pulled off running identical cars to trouble shoot with. This is the first posting i made on this forum but i've been a regular viewer to help me figure out stuff when im wrenching. i will keep this post updated with any help i get as to help any future r56 owners fix their problems.

A little history on this r56 im having the surging issue with. I bought it with 80k miles with a known timing chain problem. got it back to the garage and diagnosed the bad chain, a couple of bad coils, and two bad injectors. Pulled the head and had it machined with new vales and seals, got a new set of factory coils, and a used set of injectors, all 4 plus the rail and sensor off a known good car with 50k miles. put it all back with new bolts, gasket, ect. when i started it up the first time, i got a engine ventilation activation code. i guess someone took the relay out when the car was sitting so i put in a new relay and that code disappeared. then had the surging issue so i assumed it was the bad thermostat since it went away when warm so i replaced with a new thermostat and bled the system of air. also noticed i had the heater hoses backwards then so that was corrected but still surges. so i go on this forum and the obvious answer was the HPFP. So changed that out with not one but two other known good running HPFP and still surges. Here are the other things ive swapped out with this car. one at a time, each time waiting for the car to cool down each time so i could replicate the results. Ive been tinkering with this car for about two weeks now. its the only car out of 7-8 i have that i cant figure out so some combined brain power of this forum might possibly help my slay this demon. Also of note is that this is the only automatic car i have, maybe that might have some effect on the issue? also for the life of me, i cannot get the tpms to reset. i assume that its wheel sensor related. dont think it has anything to do with this surging issue but i figure i mention it just in case.

These parts ive pulled off my other known good running 2007 cooper s 6 speed and swapped it with this automatic cooper s and none have fixed this surging idle problem.
HPFP (twice), intake manifold with throttle body, injectors with rails and sensor, both vacuum solenoids located under the manifold, maf, both sensors downstream of the inter cooler, all coils, plugs, valve cover, pvc line from cover to manifold, vacuum pump, i also changed the oil with synthetic 5-40 or whatever mini recommends for summer, changed the fuel filter, and triple check the engine timing with plug in the flywheel and factory timing clamps on the intake and exhaust cams.

my last thing i could think would be a major vacuum leak could cause this but ive checked the obvious so if anyone has an opinion please chime in. thanks

the file is too large to upload to this forums attachment link so here is a direct link to the video.

https://1drv.ms/v/s!AsQW-7BjNyX7h2suvCd7DRSIs8DV


recent videos with better audio:

https://1drv.ms/v/s!AsQW-7BjNyX7h3CkDEet2WQ7x83E

https://1drv.ms/v/s!AsQW-7BjNyX7h3GgsfbKPYgRdbyN

 

With your Launch Creader,, just to positively eliminate the HPFP, or some connection.
Read fuel pressure while driving cold and bucking. After it warms up, is the fuel pressure the same?
Using the reader, does the engine temp range seem logical, proper cold and warm range?

Just a WAG.

 

Fuels pressure ranges from 4200 -5300 on all three of the HPFP I’ve installed at idle which seems normal more or less. The temp starts at 20-30 c and rises proportionally as the engine heats up to 100 and goes from 105-98 c as it’s driven to temp.

 

I’ve been doing some reading on some of these other surging idle posts and I’m grasping at straws here but it’s mentioned something about a dropped valve seat as well as possible bad BOV. Heck I’ve already changed out 70% of the possible engine parts, might as well attack the other 30% right? Wudda you guys think?

 

Hard to believe the engine could drop a valve seat and not manifest more than just a surging idle. A valve seat that drops out of the head gets hammered into the head/piston and it is rare the engine survives this without first manifesting some real horrific symptoms before you see a hole in the side of the block.

As for a bad BOV should be easy to determine if this is bad or not. If not too expensive you could even throw a new one at the behavior.

I would have liked the coolant or intake air temperature sensor to be at fault especially since the behavior gets less bad as the engine warms up. This could be a temperature sensor that is not reflecting the actual temperature when cold -- reading warmer -- and the behavior is the engine running lean as the engine controller fails to add extra fuel as would normally be the case at a cold start.

An intake leak is always a possibility.

In these cases when the engine received so much attention over a short span of time any number of things could be to blame. A intake air leak, bad sensor or just a bad connection. An intermittently failing fuel pump as someone mentioned and so on.

 

Tony,

Do you have a helper that can bring the idle up a few hundred rpm, and listen to the intake. I am guessing something is wrong there, possibly the BOV..
And if so, surprised no pending codes are showing yet.

Look over all the connections, your experience you should be able to list them all out on a checklist, then go to them one at a time and verify good connection by reseating them.

Really sounds like a mystery!

 

agreed, i just saw that on another post about surging idles and figure id mention it

also agreed, my 07 mcs hasnt been torn apart in at least two days now so its about time.. lol

my initial impressions as well, also thought to include the oil viscosity so i changed the oil to summer spec.ed as well as swap out the coolant, intake temp sensor, as well as the one on top of the manifold, pretty much all the pre turbo and post turbo sensors, with know good sensors. i also changed the o2 sensors with new factory sensors, and verified those sensors are accurate with them in the 07 mcs though sucessfull smog computer reset routine.

all roads lead to the bov as of right now and ill tackle that tonight and report back in the am..

 

And the winner is......
Well its not the BOV.... lol... I replaced the Bov from my 07 MCS and still the same problem. I did run it through my launch scanner and noticed something peculiar this time round though, I noticed that the high pressure is sitting around the same as my 07 mcs at idle, jumps roughly from around 48-5100 which is normal.
When i first start the car, it doesn't surge all the time, mostly it idles ok for a bit, but when i put it in gear and drive around ,it surges at a complete stop, or it'll idle for a bit ok then go into a surging routine. Now im watching it whenever it surges up and down and the pressure stays above 6500 each time it surges. when i rev it up while its idling at a stable 5k pressure on the high pressure side, it goes up and stays up at past 6500. My red 07 MCS pressure goes up and down when im test driving it for comparison purposes, but the pressure always goes back down to a stable 49-51k at idle.

My question is that is there another high pressure sensor or any other sensor i am not aware of that would make the fluctuating pressure readings i see. im almost convinced that its the high pressures im seeing in my fuel rail thats causing this funky idle. i have previously swapped the entire fuel injection rail with all 4 injectors and the high pressure sensor along with it and left it in the car so the rail and injectors are a known good item.

on a side note, it took me about a week to get the BOV installed and reported back to this thread cause i got side tracked with another mini project. I found a 2013 countryman for sale and the poor owner wasn't too technical. He had the freeze/machining plug literally fall out while he was driving and the dealer told him his engine was trash and it overheat and needed a complete replacement. well the cost of a new engine from the dealer was more than whats the cars worth. Needless to say, i got the car for cheap, towed it home and within a couple hours and a beer, im driving a new 13 country man now.
my drive ways looks like im getting ready to remake a scene from "The Italian Job". i think im going to sell off most to all of my mini's, i just have to many right. i guess look in the classified of this forum if your in the bay area and need a well maintained with rebuilt motor mini cooper. I have 05 mk-1 with 108k, 07 mk-2 MCS with 103k miles, this blue one here after i figure out this idling problem, and probably the 13 countryman. it has 70k or so on it. im asking 28 for the mk-1, 32 for the 07 mcs, 35 for this blue one, and like 87 for the countryman. their all recently smogged so its ready to sell.

oh i mentioned the countryman cause these new cars now require battery registration into the ECU for it to work properly. I dont know if this is required on these mk-2 r56's, but i have noticed a little side box next to my battery on some of my r56's so im thinking maybe some models have the IBS (intelligent Battery System) and i need to register the battery? maybe its an electronic thing thats causing this surging?
Im getting a couple of low voltage check engine errors that's causing misfiring codes as well on the countryman so im forced to buy a dealer level bmw scanner that has the battery registration function. im gonna run this new scanner on this blue surging cooper and report back to see if you guys can help me with diagnosis.

 

I was offered the IBS as an option when I bought my 2009 R56 new at the dealership. I'm glad I didn´t get it - I've changed the battery a couple of times with no apparent issues.

Have you decided on the scanner you are getting? If so, does it work for you? I'm looking for one I can trust. I don't want to jump over topics here but since you are already on it...

Cheers