I have had my R53 for not quite a year and love it. Only issue, until recently, was having to replace the water pump in January. Now, it drives great, but after about two hours of stop and go traffic in the Denver area (80-95 degrees outside temps) the car first hesitates and then in any gear just loses power and will sometimes just stall. If I sit for 30 minutes with the car off, it seems to run fine for about 45 minutes to an hour before it starts again.

My first thought was carbon clogging the fuel injectors, so I cleaned them, but it just got worse. I am wondering about the Supercharger By-Pass Valve. I can squeeze my finger into where the valve is and move it pretty easy with one finger, feels like little to no resistance.

I am posting this because while I found similar issues, none exactly like mine, or that I thought was the same. With it being Memorial day weekend, I am kinda stuck self diagnosing until Tuesday. I would like to be able to take care of this myself, and know I can fix most issues, but Tuesday I will take it into the shop to have them run a diagnostic on it, but until then, your help would be greatly appreciated.

Carl
2005 Mini Cooper S R53
British Racing Green

 

Are you getting engine lights/codes?

The bad bypass valve would be no power but I am not thinking it would stall the car. May have some other leaks and the OBD2 codes would help more.

Going to suggest that you also post this over at Motoring Alliance, they are another MINI forum that we are working with to help MINI owners. Tell them I suggested them.

The other thing is to try a dollar bill test to see if there are valve issues. The second link will take you to a thread that I just posted a video for the test, third post.

www.motoringalliance.com


https://www.northamericanmotoring.co...-ballpark.html

 

Not throwing any codes. The car sometimes will stall out. Most of the time it will lose power but idle, but sometimes it will stall completely. A compression start usually works and gets me off the road or to the side at least. Like I said, for the first few hours of driving, it is fine, then suddenly, almost like vapor lock symptoms, I will get on the gas, but the rpms drop to idle or stalls out.

 

Bad fuel pump? Fuel filter clogging after extended run times?

 

update:
Took the car to my mechanic. TThey hooked up to the computer and there were no errors logged. Oil was low, and a wire going to the coils/ignition was badly frayed. They replaced the wire, did an oil change and thought that would solve it. Went out tonight to drive for Uber Eats, and after 2 ½ hours of stop and go traffic, I lost power. Just for a second, but just like before. Then I drove home, about 5 miles, with no problem. I am hoping that it was a hiccup from the half tank of gas I have with the lucas FI cleaner in it. My mechanic also said my clutch is slipping and will need to be tackled soon. he quoted $2k to fix that. So, please, Thoughts? I am planning a 1500 mile drive soon and do not want the car to give out on me every 3 hours.

 

Was the mechanic a MINI shop?

 

specializes in BMW/Mini and Benz