New to the mini world, we own a small repair shop and I thought it would be fun to own one. Bought one that needed a clutch to start with. We have put a new Frankenturbo F21M, oil pan gasket, oil pump chain, timing chains, sprockets and new tubes. Pretty much whatever ECS recommended for the job we did. There is no tuning in this car and we cannot get rid of the codes 2C57 and 2C91 under light load. Any thoughts? I am looking to sell this car but would like to get it running right before we do that. Since we bought it undriveable we don't know if its ever run properly and being in a small town we don't have much to compare it to.

 

I like to use this site to interpret those BMW/Mini codes:
https://bmwfault.codes

2C57 means charge pressure is too low.
And, interesting… 2C91 apparently means the diverter valve is failed open.

My first suggestion would be to pull the diverter and check for proper operation, and make sure it’s all in one piece. Could be an easy fix.

 

Yes we have tested for any leaks, we have tested vacuum and we also replaced the diverter valve after doing the turbo.

 

Did you replace the diverter with a used one? Sometimes those diaphragms can look good from the outside, but have a tear that isn’t noticeable until disassembled. I’ve also heard to of aftermarket valves not seating properly in the turbo and leaking under pressure.

Do you have a mechanical boost gauge in the car? What is it producing for boost?