Hi everyone,

on my 2014 N18 Clubman, I recently replaced my thermostat, cross over pipe and valve cover. The valve cover is an aftermarket Bremmen Parts one from ECS. I did remove the intake to do the cross over pipe.

After completing that work, I am getting a CEL with code 2BC0 (Mixture Control, fuel air mixture too lean). It also showed the same code saying Bank 1 too lean. I have also seen an 2775 Air Mass Plausiblity too low and 2BF4 Fuel pressure sensor plausiblity, pressure too high before start. I have an NM open element filter, not sure how it would have gotten clogged by just taking it off, but I will replace that first.

What I have done:

• sprayed all the connections on the intake pipe, valve cover, and PCV that had been removed to try and find leaks. Nothing
• cleaned the MAF
• I used new gaskets on the intake ports when I reconnected it and torqued to spec

So am I right in thinking the next step is to try and do a smoke test to see if I can find an unmetered air leak? I've purchased a machine, but never hooked one up before and wanted some advice. I was planning to connect it after the MAF, and just plug the exhaust pipes and let it run and look for leaks.

Hopefully this will help me find the leak so I can remedy whatever is causing the leak. All guidance and advice is appreciated as this is my first go around using a smoke machine for tracing air leaks.

Thanks in advance!

MJ

Find out where the leak is, I was going to go to the auto store see what they have as a sealant for air intake plumbing.
for a r56

Did you make sure to reconnect your fuel tank breather line to the intake manifold?

If you're going to smoke test the intake, you can't connect where the MAF sensor is since it's on the inlet to the air filter. You could remove the pressure sensor on the intake manifold. That would be your best bet. Make sure to disconnect the charge air pipe at the inlet of the throttle body and plug the throttle body with one of the caps that comes with the smoke machine.

Thanks! I have an NM intake, so I was able to disconnect just past the MAF. Smoke started coming out of the right front corner of the valve cover, so I'll pull it today and check my RTV job. I'll also double check the tank breather line. Thank you!

MJ

Is there a viable unit that is reasonably priced?
ECS sells a couple around 900$ while they probably work quite well for a one use tool is expensive.
any other good options?

Any updates on solutions?

Hi there, I was able to resolve it in replacing the valve cover and resealing the new one very carefully.

I bought this unit: There are many that work, I just got the one with extra pressure adjustment so I could generate enough pressure to leak.

Congratulations on the fix and thank you for posting the solution for the community!