So I decided to tackle replacing my thermostat housing as well as my coolant reservoir as I was getting a slow coolant leak from that side of the engine.

I followed directions very closely and even marked most of my wires and coolant tubes.

After refilling the coolant and burping the system the car started without an issue, I turned the heaters on in the car for about 5 minutes to hope the thermostat opens and then burped it again. After this I decided to take it on a test drive and any time I hit boost (even just changing gears) I get heavy stuttering, loss of power, and I even heard what may have been a knocking sound one time when I hit boost.

I don't have any codes popping up with my OBD reader and I'm at a loss.. Really dreading that I messed something up severely.

 

Just took the car for a drive again, the "half power warning light" came on(looks like a check engine light however no codes are stored when I try and read it with my OBDII reader)

 

Did you use the bleeder screw while the car was running? I think the electrical connectors are different than each other, so that might not be the issue. Did you confirm that the vacuum hose is installed on the turbo?

Mike

 

Re-checked all my vacuum hoses this morning.

Did not bleed the system while the car was running, I followed Mod Mini's video on replacing the thermostat housing.

There is a wire that is connected to the side of the ECU with nothing plugged into the plug, if I recall correctly when I was taking everything apart I thought it was a sensor of some sort, but in Mod Mini's video he plugs something into it. That being said, I have a manual and the car he's working on is an automatic. I've tried to find diagrams online to figure out what this plug is but I've had no luck. It comes out the side of the ECU wiring and then twists on to the side of the ECU.

 

At 15 minutes 11 seconds in his video he plugs it back in, but I have no wire leading to this area except the top wire that turns 45 degrees to snap into the side of the ECU.

 

I replaced the thermostat sensor with my old thermostat sensor (I had a leak coming from my old thermostat), and the stuttering and misfires 'seemed' to have gone away? but the half power engine light came back on again. Not sure where to look now, I took the car for a 10 minute drive and I didn't feel any major performance problems or hear anything strange but it was also raining loudly and anything is better than how the car ran last night.



EDIT: Nope, nevermind. Still misfiring. Also almost sounds like whistling from the engine bay, could be a vacuum leak? but all my vacuum lines are connected and seem to be in good shape.

 

Getting code CC-ID 029 when I mess with the trip computer.

 

That code is useless, you need to have the computer scanned via a proper scan tool. If you're getting a whistling noise from the engine bay chances are that you do indeed have a vacuum leak.

There are two connectors that are interchangeable in that area, and if you mix them up you will cause problems. The temp sensor connector has a green tip and the PCV heater has a brown tip. If you have them confused you will run into problems.

 

Car is at the MINI dealer for diagnostics, will have to suffer through a 2016 328ix for the weekend