My 07S has had an issue for the last couple months where it will lose a lot of power temporarily. It normally happens after not driving the car for a few hours, and it happens within the first few minutes of starting up. When I accelerate from a stop sign, it feels like it has lost 120hp, or on the freeway there's very little acceleration in any gear. It feels like there's no boost.

This happens about 1 in 5 times that I drive the car. I find that if I turn the car on and off again, it gets better, and today I was able to fix it by putting it in neutral, lifting off and let the revs drop to idle for a second while cruising. When I put it back in gear, it was fine. Today it also started jerking at and near idle with very slight throttle application.

In the past year I've had the timing chain recall done, thermostat housing and oil filter housings replaced, and after the issue started, the dealer replaced the coil packs because the car wouldn't start, but that didn't help the power loss issue.

A well known local mini shop couldn't reproduce the issue but cleaned the MAF and did a compression (~190 in all cylinders). Based on their test drive, they said it did not need walnut shell blasting.

Any suggestions are appreciated.

 

I'd pull the recirc valve and look at it.

 

I just pulled it out. Moves in and out ok, no apparent damage to the diaphragm or seals. Put it back in, drove the car and had the power loss for 20-30seconds or so.

Is there anything else I should be looking for on the DV other than a visual inspection?

 

Two other things come to mind. Throttle body and HPFP. Both are known to cause similar problems with lost power. Do you have access to a fault code reader or data logger to read fuel rail pressure? Also you didn't mention it but are you getting a CEL when it happens? In the N14's the throttle body is fully active whereas the N18 uses Valvetronic as the throttle and the throttle body is normally fully open except when the engine is cold. A lot of times having the dealer re-calibrate the throttle body will resolve that issue. HPFP's are expensive little buggers.

 

No CEL.

 

Update:

Replaced my diverter valve. Compared to the oil one, the new one doesn't return to the closed position as quickly and gets stuck just shy of closed sometimes.

Good news and bad news . . . I drove it for about 20 minutes and could not get the issue to go away, so it's more consistent, and the power loss feels the same all the time, rather than -20hp sometimes and -80hp sometimes. So the diverter valve was definitely going bad, but that wasn't the root cause of my issue.

 

Did you ever get this resolved? Im also having a significant power loss issue with no consistent CEL and been trying to investigate the root cause.

 

Nope. The car has been at the dealer for over 2.5 months (Thank god I asked for a loaner car). They've replaced the both fuel pumps, injectors, turbo, intake manifold, some Vanos parts that the service writer wasn't very clear on, Every single part of the air intake tubing. At some point in the process the car started idling poorly and now throws a CEL for un-metered downstream air. Smoke tests show no leaks and all sensors and systems check out fine. The dealer is completely stumped and is basically just trying random stuff at this point. I don't blame them, because I couldn't figure it out either, and nothing it does makes sense. Luckily they are being very reasonable as far as what they are charging me for all the parts that they are throwing at it.

The 228i track pack I ordered will be here at the end of the month, and I will never be more happy to see a car go than when I leave this POS at the BMW dealer. I literally don't even care what they give me for a trade in, I just want it gone. It served me well for 3 years, but this thing has been a complete disaster since it crossed 70k miles.

Reading around on the forums tells me that my experience is not an isolated incident. You guys with 07-010 Mini's are sitting on ticking time bombs. Dump them while you can.

 

Boost problems? no cel? Pressure conventer or tank air vent valve. Common issue,loosing/leaking boost,the boost is controlled by wrong way.Sometimes hard to find,because part is electrically ok but mechanically broken,thats why no CELs.Location under intake manifold.

 

Exactly where is the pressure converter?

 

So the car has been at the dealer for 3 months. They say the boost issue has been solved after replacing the turbo, but they have been chasing an idle problem for the past month to no avail. They have literally replaced every part outside of the longblock, and they called me today and said there is nothing left for them to do, so I'm going to the dealer on Monday to take a look at the car with the tech and service manager.

The dealership has been more than reasonable as far as what they are charging me for the work, but I'm still left with a car that doesn't run right. I'm going to post a new thread about the idle problems.

I guess the good part is that if I can sort out the idle, I'll have a basically new 2007 Mini to play around with, but the downside is that I've already bought a car to replace it (didn't expect it to be in the shop for 3 months!)

 

3 months, that's crazy! How many miles does your 07S have on it? Not all 07-10 MCS have problems, mine has been stellar since I have owned it. I have had mechanics tell me my engine runs really smooth and idles better than what their used to. I hate to say this but you might have been better of taking it to the dealer as they have special tools and diagnostics that can read codes others can't. Lets see how long it takes the Mini dealer to find the problem.

I still believe in finding a good local shop for the well known issues (timing chains etc.), but some issues are better handled by a competent dealer.

 

It IS at a dealer. And they have been working with engineers from MiniUSA to diagnose the problem.

My 07 has about 72k miles on it. From what I have seen, read and experienced, all 07-10 MCS WILL have problems sooner or later. It's just a matter of when.

 

Amazing that a dealer will give up and just give a poorly functioning vehicle back to the customer. I would consider finding a good independent..

 

You have it backwards, he had it at an independent shop who gave up and independent shop suggested taking it to the dealer where it's at now. It will be interesting to see what the dealer does.

 

Miss Susan (my neighbor) was complaining about this same issue with her R56, and I suggested she just change Fuel Suppliers (find a non 10% methanol) and go on and fill it up with some 93, then after that go to the Mid grade during the winter... She did and now she claims the issue has not manifested itself since.

(I tend to always run 93+ and non methanol in mine, so I haven't had it)

Motor on!

 

-Sorry,my reply takes a little time...It is under intake manifold, same location as tank air valve and it is like vacuum controller.Today I remember of this thread, my friend has been a mystical power/boost problem and today He found the solution.He has been checking/replace this sensors(tank air valve and press.converter),divert,all hoses,new downpipe,wastegate actuator etc.Main problem was jamming and leaking wastegate inside of turbo.Sometimes it will work normally and often it does not closed tightly,leaking pressures.No Cels.