2003 Cooper S, June build, 6 speed, 30.000 miles. My dealer is stumped, power loss happened 9/19, has been in for service four times since power loss, the last time they kept the car for a week (gave me a loaner). No service attemped yet except reflashing the DME twice. Mini rep will be looking at the car early December. Dealer did not attempt repairs because no error/fault codes show.

Symptoms: 35% loss of power (IMO) below 4,250 in all gears. Once above 4,250 power returns quickly, not instantly. Car feels like it has a turbocharger with a long delayed lag till boost arrives. Dealer drove with me and commented on the lack of power when I jammed the accelerator to the floor and the car leisurely accelerated until higher rpms. Travelling at 60 mph in 6th gear, the car will not accelerate unless downshifted to 4th, 5th does not help much.

No unusual noises except harmonic balancer/belt tensioner/pulley chatter that I have had checked by dealer numerous times one year prior to loss of power. Dealer confirmed belt and tensioner within spec at last attempt to rectify power loss. Gas consumption is down about 5-9 mpg since loss of power, but I attribute the poor gas mileage to having to give the car more gas to accelerate.

At the dealer I test drove a 2003 Cooper S with 25,000 miles and my car is definately suffering from a loss of low end power, the car I test drove felt great. The car I test drove had the same harmonic balancer/belt tensioner/pulley chatter as mine so who knows?

My guess at possible causes of my loss of power: Partial supercharger failure (pressure leak, binding bearings, seal leaking)? Fuel pump failing? Clutch is NOT slipping.

Anyone have any ideas to add? Has anyone experienced something similiar? Please no dealer/manufacturer ranting or trashing, just some helpful suggestions.

Thank-you

 

There's a very simple reason for the power-loss. The Bypass Valve is either binding in an open or partially open position, allowing a very low amount of boost to build up in the manifold. If you call us I can walk you thru the
very simple way to check the valve.....

peter
Team M7
562-712-3270

 

Thank you for your suggestion M7, my dealer gave the bypass valve some thought but has not addressed it yet. I am adding your suggestion to my list of possible fixes when the mini rep arrives.

 

This is typical - "No repairs were attempted because no code was found". The car is sitting in their shop with no power! Why look for a code to tell them how to fix it? What happened to mechanics that know how to fix cars? All we have now are "technicians" that can read codes. I $25 scanner can do that. Codes do not tell you what is broken. The code tells you what diagnostic procedure to follow. If the car is not running properly and there is no code, then a MECHANIC will need to diagnose the problem! This is not rocket science, it is auto mechanics 101.
Thanks for letting me vent!

 

From a brief conversation with a MINI tech, I found out that it is very difficult for them to get MINI to pay them for the warranty work on engine stuff unless they can provide the error code. Why spend time on your car and potentially not get paid, when 10 other cars are lined up where they can pay? Wierd buraucracy, eh?

stustan, try zip-tying your S/C bypass valve shut and see if that helps your low end power. Of course this is not the final check since that valve could also not be sealing perfectly when closed.

 

11/23 Dealer ordered new bypass valve and will install at my convenience at end of next week, hope that cures it. I will post results, and thanks for all suggestions. If any other ideas pop up please post.

 

try zip-tying your S/C bypass valve shut (you can do this without removing or undoing anything from the engine) and see if that helps your low end power. Of course this is not the final check since that valve could also not be sealing perfectly when closed.

 

Dropped off my car at dealer today (12/1), they gave me a 325i automatic as a loaner. Am I crazy or what, I prefer my Mini S!

 

Dealer installed new by-pass valve, no change at all! Dealer is awaiting a newly redesigned secondary part to the by-pass valve due to ship from Germany on 12/20, I am #4 in the USA to receive the part, will post follow up after install. Dealer says the new part will be part of a by-pass valve recall.

 

Bypass valve was my guess as well. And no, I don't blame you for preferring the MINI to the 325i - know how you feel.

Good luck with the "secondary part" (whatever THAT is...) and hope it cures the problem.

 

Most of you guys were right! Thanks. My dealer installed the new updated bypass valve and my car feels just perfect. The old valve never shut completely.

 

Glad you got it fixed - and thanks for the update.

 

This is the first I heard of a recall on the by-pass. Has anyone heard any more on this? I just had a by-pass replaced and would be a bit bummed if the part is now upgraded.

Rich

 

I wouldn't worry Rich, if you car feels right then you should be fine. If you must.....see my earlier posts on the SUPERCHARGER BYPASS VALVE thread and get the new part # and ask you dealer to install the new updated valve. I honestly think that the old valve should last you a while.