You mention that you put on a cold air intake recently, but have removed it to test if that was causing the problem. Is it back on? If so, you may have simply over-oiled the filter element. This is very common as they don't need nearly as much as you might think.

 

This makes sense.... Lots of people over oil the filter. Still not sure about the MAF though... Anyone with solid knowledge know if one is on there? As I said, I have never seen one.

 

I also have an R53 that is sluggish below 4K rpm. It gets lame mileage (22mpg tops). As an example of the low-rpm sluggishness, it is impossible to spin the wheels from a standing stop on dry pavement with the dsc off (not that I would want to, but it ought to be possible, no?).

It has an oiled K&N air filter installed by the PO and I would not be surprised if it had been over oiled. I was thus excited about cleaning the MAF -- until I realized that the R53 doesn't have one! It has a couple of MAP sensors, but I think they are quite different. Might an oil-fouled MAP show similar symptoms to an oil-fouled MAF?

My best guess is that it is a malfunctioning bypass valve and I am thinking of swapping for one of the Detroit Tuned ones. Does anyone think that a bad bpv could cause the low mileage in addition to the low-rpm sluggishness?

 

NO~~~~~~~~~~But an o2 sensor WILL OBEY

 

02 sensor is a good thought. but I think that would register problems all over the RPM range. The mechanic who told you to drive until it gets worse isnt wrong, if it is a real problem it will get worse. and then become diagnosable.

However, if it is something fouled in the intake track (MAP/MAF whatever we have) some fast aggressive driving should help clean it. i'm talking some prolonged higher revs, get some heat running through it. makes minis happy...

what have you tried that has been posted, what are your results?

 

thank you all for all your input. I would really love to find out the real source of this problem. I am thinking the next step should replace the supercharge belt and then the by pass valve. I took the car for a spin on last night and it start to drive perfectly, and after a few hard charging drive, the problem start to appear, especially on the second gear getting our of the corner. It drives perfectly again on this morning (no sluggish at all), it pulls hard after 4000rpm. I still love my Mini and I really don't want to sell it (I just need to get it back to good health). thank you all again for your help.

 

THIS PROBLEM IS CALLED HEAT SOAK.

seriously, does this only happen after driving for a while?

dont just throw parts at a problem, find out what it is, PROPER DIAGNOSIS....

 

That and 30,000 miles on an OEM belt with a 15%...and the AC on....

HAS the basic mantaince been completed?
You did not say if you have replaced the spark plugs,,,should be done on the same schedule as the JCW's....at inspection 1 and 2...not the S schedule...and are you running stock plugs? These will cause a hesitation with a pulley in warm temps....as will poor quality gas.

Basic stuff....rule them out. then dig deeper!!

 

This oil accumulation is interesting... there is very little oil in the supercharger, even less as the car ages, so getting a significant amount on this sensor, sounds not likely to me. Where is this sensor located?

 

with a cool engine, reach down behind the air horn and manually operate the diaphragm (push it in) it should, under spring return, return to its original position. I had a return spring actually break. https://www.northamericanmotoring.co...ysis-pics.html

If the shaft is tight and returns, it is probably not the bpv, unless the diaphragm is torn (you could test with vacuum pump).

 

It would be good if this could be resolved- this is a problem for many. I have it, there is some mention in the yo-yo chronicles as well. It is not heat soak-I have it all the time-cold, warm, does not matter. I did plugs,wires, pcv valve, fuel filter, air filter. No codes stored. Would love to figure this out. My newest lead is a possible vacuum leak at intake of SC. Regarding the o2 sensors- I have heard that you do not need to change unless they are throwing a code.

 

oh yeah, also zip tied BPV closed-no effect at all.

 

I replied to this a long time ago...

1 Question and 1 Thought.

Is yours an automatic transmission?

I absolutely hate the "electronic accelerator" in this car. I almost kill the car on a daily basis because of this. A cable to the throttle body is so much faster and responds quicker, but some idiot at BMW thought an electronic accelerator would be a good idea. He should be shot.

The accelerator causes a lot of problems and is my #1 PEEVE with the MINI.

 

I agree with above, but whatever the problem is that is causing this issue, is not just because it is drive by wire- i say this because, I would not have bought this car if it drove like this from the factory, it is an acquired problem. Mine is a manual. I have seen many people say- "just rev it ti 2000 rpm, then let out clutch". If you drive it this way and shift every time at 5000+ rpm, you will not notice this. Unfortunately, while I drive this way sometimes, it is not how I drive the majority of the time, and this is the real problem and these are not the solutions.

 

Hummm

Just a thought but have you used fuel injection cleaner on a regular basis ?

I use it in my 06 MCS Auto every month, and so far no problems . . . . . . . .

 

No, but always premium gas. Tried BG44k cleaner and seafoam, no improvement.

 

Here is another thought.

Have you tried re-setting the ECU ???

I guess the easy way would be to remove the positive battery cable for
5 minutes, then reconnect and go take it for a drive.

Also, look up under " search " to see if that is the best way to reset the ECU...........

Hope it works

 

Contact this NAM member: he is a Mini Tech so maybe he can help

Certified Mini/ BMW technician Please Check out and follow my Blog ! --> http://www.theultimateautomotiveblog.blogspot.com/
And Twitter @UltAutoBlog

 

Thanks for the reference. I have reset the ECU as well

 

The dip just below 3k seems to be pretty common in these cars. Just look at many of the dyno charts and you can see it. I'm not sure that is what you are describing, but I don't think that totally goes away without some custom tuning, even then it seems common.

 

I have the exact same problem.

HRM if you look at any dyno chart, you'll see that dip at 3000rpm...make it about 2 or 3 times deeper than on the chart (and only when you're at partial throttle) -> that's what the problem feels like.

My car always had a slight loss of power at 3000rpms - but it's gotten worse and worse with time. It's somehow acquired. Some gunk somewhere that I need to track down and clean.

I've done everything other posters have done: plugs, wires, coil, seafoam, BG44k, fuel filter, BPV, PCV valve, air filter, resetting ECU (at MINI with their tool). No luck - everything I did made it slightly better (fuel filter most of all), but the pronounced dip at 3000rpms is still there. At times I thought I had it fixed, but it always shows it's head again within a few days.

The car's also refusing to throw any sort of error code.

Ironically the car works beautifully around a track - the combination of large throttle openings and high revs filters out the problem.

 

did anyone ever find out the issue? mine is also having this problem

 

Try manually closing the bypass valve with a zip tie....
sometimes they refuse to close or get sticky (or the spring breaks) and the results is your car gets boost MUCH later or NEVER..so it will be very sluggish...worse than the Just-a-cooper...due to the lower compression ratio on the S (to allow for the forced induction..once the compressed air is forced in from the boost, it is functionally more than a cooper).
the bypass valve in the S dumps the SC boost below a set rpm...allowing the SC to spin freely, and the car to idle/run at low rpm's as a normaly asperated car...giving better fuel economy due to the near total loss of the parasitic drag from the SC.
The YO-YO, or loss of power, common on many S's around 3000 rpm is usually attritibed to the closing of the valve, and the computer adjusting to the change...some versions of software on the computer and some cars had more issues than others...
for a bit MANY MANY versions of updated software came from MINI to try to fix the yoyo feel...
but general poor performance, and 0 codes...I'd look at the bypass..might be stuck open.

 

sorry i don't know where the bypass valve is...can someone tell me or show me where it would be and how to get to it? thanks

 

I think there is another thread discussing the same problem "engine stumble, a different type" (I would put a link to this if I knew how). My guess is this is a pretty common problem and there are other threads on it. At this point I am going with a leaky SC inlet gasket (profile gasket in the following quoted post). I have done lots of other stuff to no avail. Now I need to get up the ***** to tackle this repair and service the SC while I am at it. Also, the VGS does not fix stumble, but in my opinion improves the overall drivability.

Following quote is from the above noted thread:

"I killed 5 birds with one stone, about a month ago i was chasing a miss, stumble, hesitation, i had poor off idle throttle response, I took out the sensor in the front of the intake, made a rubber nipple to adapt it to a smoke machine, After plugging off air filter with a bummer glove over the nipple for my filter in the Alta box i filled the engine with smoke, i kept getting a trail from some where low on front of motor, hard to pin point with fan and radaitor in the way,

So i ordered a "Profile" gasket one from air intake tube between throttle body and supercharger, Week later i took front of car off,

I re smoke tested with front of car off, I did have a leak at this gasket,

I did find the service records from my car, it did have a clutch at 31,000 miles, So maybe a Reinstallation mishap.

While i was in there, i changed super charger oil, oil pan gasket, Welded in baffles like mini mania pan,

But i also notice the rubber elbows one on fuel pressure regulator rotted and cracking, also one to on intake end to hard plastic line heading back on left side of valve cover, So i just replaced all the vacuum lines, But as factory had them, I did it this way and drove it a few days before changing them For the VGS set up As in this post
https://www.northamericanmotoring.com...ystem-vgs.html

Car is running amasingly better, just wish i had a local BWM dealer to reset my ECM"