Loss of Power - MINI Cooper Forum

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post #1 of 4 (permalink) Old Apr 8th, 2014, 02:34 PM Thread Starter
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Loss of Power

Hi all,

Im new to this forum and know very little about the Cooper S.

The Mrshas just bought a JCW 2004 with 80k on the clock and all was fine and pulled hard but now 3 months in its like the car has no boost.

You can hear the supercharger whining but its like there is very little pull.

I have read about bypass valve being an issue could this be hers?

She went to "a specialist" today who advised the CAT could be blocked which i do not believe.

The only other thing we are doing is the usual plugs,leads etc.

Any help would be massively appreciated.

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post #2 of 4 (permalink) Old Apr 8th, 2014, 05:21 PM
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if the bypass valve stays open at high revs with your foot down it sometimes can put the engine management light on. One way you can test it is when the car is switched off the bypass valve should be shut, you can then cable tie it shut & take it for a run & see if you still have the problem if you do there is a good chance it could be the cat. Its not really advisable to leave the bypass valve tied shut though as it will drink fuel just use it as a test

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post #3 of 4 (permalink) Old Apr 9th, 2014, 08:29 AM
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When you say she took it to a 'specialist' and they said the CAT is blocked why wouldn't you believe them?

One of the other causes of power loss on the supercharged 'S' is if the intercooler hoses are split/leaking which I understand is not uncommon on the older/high mileage engines.

If you took it to one of any of the independant specialists as recommended by many users of this forum I would expect them to very quickly diagnose the problem for you.

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post #4 of 4 (permalink) Old Apr 9th, 2014, 09:52 AM Thread Starter
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When i got home last night i turned the car off and unplugged the vacum home off the valve took it down the road and back to life it was. I think this answered my question.
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