Hoping one of you can help me or point me in the right direction
Ever since I have had my 08 Cooper S, there has been a lack of power. I thought nothing of it as I had nothing to compare it to. The car is driven mostly by the wife.
I recently had it in a garage to have a service done and was told that the turbo is not working at all
The garage connected it to a diagnostic machine, no error code. Played around with turbo to ensure the parts are working as they should, all fine. He then traced the vacuum pipe which connects to the turbo and it went all the way back to the pressure regulator valve. He thought maybe this wasnt working as should and bypassed the valve by disconnecting the in + out pipe and connecting together temporarily. Fired the car up, took it for a gentle spin and straight away the power was awesome, turbo doing its job but obvious overboost as there wasnt a valve in place to regulate the pressure/boost. I ordered a new valve (attached) from Mini and replaced the old one. Connected everything back up as normal, took the car for a drive and still no boost!
Is there something obvious that I am missing or any checks which i should do? The turbo is obviously working as we bypassed the valve and everything is fine. Any pointers would be great...
Am thinking that your pressure converter is actually okay. Connecting the in/out together just bypasses the pressure converter and doesn't necessarily prove it's defective.
Not hugely familiar with the S setup, but on the diesel engine variants the pressure converter adjusts the VNT mechanism based on measured manifold pressure. So maybe your MAP sensor is bad. Either that or the electrical connection to the pressure converter is bad.
Am curious about this as I also have a lack of power on my Cooper D and no error codes showing...
Thanks for taking time to respond. Some good pointers which I will be sure to take a look at. Failing those, I don't think I want to waste any more time or money on the issue. It has been suggested to me to bypass the valve again, and install a manual boost pressure along with a gauge. That way I can control the boost to a level that the S is comfortable with
Manual boost pressure and gauge won't work. ECU will expect a mapping between manifold pressure and air to fuel and will throw codes if measured doesn't compare to reference. You'll get yourself into more difficulties taking that approach like under and over-boost conditions. Strongly advise against it.
By the way, is the MAP sensor the the part I have circled in the attached picture? This hasn't been changed yet, the only thing that was done during diagnostics was that it was unplugged, which resulted in the engine management light coming on. Does this prove proper operation?
Actually, I am also having an issue with power loss on my Clubman D and have exactly the same question as you regarding sensors and error lights. I strongly suspect that if the sensor is disconnected and it throws a CEL, then it's working properly but I am not absolutely certain.
I will order a new sensor and let you know how I get on, they aren't very expensive.
Not sure if you can entirely rely on the engine management light. Could it be that when plugged in, the car still detects the sensor as plugged in and assumes that it's working? (Even if in reality it's not doing the job). Or is it clever enough to know that although plugged in it's not working how it should?
I don't know the history of the car before I bought it, for all I know there could have been some type of error code related to this part and it was just cleared, therefore the car thinks nothing is wrong
Issue finally fixed car is now running and driving like a dream. There was some corroded wiring which was causing an issue between the electrics. The mechanic tried to explain to me exactly what was wrong, but I didn't understand too well due to the lack of knowledge I have with turbos and how the electronics of a car work
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.