hi,

r53 Cooper S owner from the Netherlands here, desperately looking for help

i had the famous stutter, so i replaced the bypass valve on my car (after first replacing the spark plugs), using this howto and now have a huge problem

i did the ecu reset as described in the howto, car started normally and all seemed fine, went for a test drive, took it slow at first and was drive fine, until i punched it so the supercharger would kick in and lost all power

engine check and EML lights came on and engine was running on 3 cylinders
i pulled over, switched off the engine, started again and it was fine again, but within half a mile it did the same. restarted again, EML light disappeared, engine check light still on, and i drove home slowly (with all 4 cylinders firing

had the computer read by a garage, 1 error code pointing to the throttle body, so i went home and took it apart to see if i had missed something
couldnt find anything tho, put it all back together and its still the same thing

it drives normal unless i punch the gas, EML and engine check come on

my questions:
firing on 3 cylinders, is that normal for 'limp mode'?
do i need to have the computer reset by BMW after installing a new bypass valve?
or could this be the throttle body itself?

i really hope someone can help me, i could drop it off at the bmw dealer but am afraid i wont be able to afford them

thanks in advance!

 

I would suggest triple checking the the connections. Make sure the bypass valve is secure on both ends with no leaks. Make sure the vacuum line to the valve is also tight.
Also, double check the rubber boots that connect to each end of the intercooler, these are real easy to install incorrectly since you can't really see the undersides of them.

 

ok, will do tomorrow, getting a replacement TB to rule that out, will recheck all hoses and make sure the rubber boots are installed properly

will the error disappear automatically if everything is ok? or does it need to be reset by computer?

thanks for your reply!

 

What was the code?

 

i dont know the exact code, guy from the garage didnt let me see, but he said bad reading from the TB

 

i had error p1688, description "manifold absolute pressure sensor 2 high voltage"

removed the error and took a testdrive, its fixed!

so it was either the throttle body i replaced, or some things simply werent reinstalled correctly, guess i'll never know, but i'm ok with that