I posted this on the other group with stock issues but no comments. Thought this might be a better place to post it (Sorry Admins, you can delete the other one. I cannot figure out how.)


Okay having an unresolved problem with a 2007 R56. Replaced engine and now getting 2b64 code on idle about every 30 seconds. Have smoke tested multiple times NO LEAKS, checked timing several times, swapped all sensors and replaced with new valve cover still having issue. When it happens my vac on intake drops for a second, fuel trims skyrocket and fuel proportioning valve rises to accommodate what it thinks is a leak. Runs and drives fine other than that, plenty of power I'm at a loss any help would be appreciated.

 

If you're getting some hiccup about every 30 seconds, at which point you get the code, then your smoke testing may not be in the same conditions that are causing the error. For instance, and I'm not even sure the idle control works this way in our cars, there could be a problem with the idle air control system, where when the valve opens far enough it exposes a hole that pulls unmetered air in. And since your smoke testing is done with the engine off, the idle control valve never opens that far.

You might be able to find the trouble using WD40, but it will be tedious because you have to get the stuff into a suspected leak area right before or during the times when it is leaking air... But I don't have any other ideas about how you cold find it.

I'd still put a nickel (of someone else's money!!) on the problem being an air leak somewhere, though.

 

Sounds pretty similar to my problem. I can't find a leak on mine either. I replaced the head only. I'm pretty certain that there isn't a separate IAC valve, I think it is all handled by the throttle since it is electrically actuated. Maybe we can compare idle values Here are mine:

MAP: 3in-Hg vacuum (fluctuates. starts higher but goes lower. Problem starts around 3)
Throttle position: between 16.8% and 20%
short term fuel trim: up to +6% (starts at 0 but goes up and fluctuates once rough idle starts)
ignition timing: between +3deg and -12 (fluctuates a LOT but usually stays near zero)
AFR: 14.7 (this actually stays pretty steady)

Above about 2000 RPM the car is mostly fine. I can feel what seems like an intermittent miss up to maybe 3000 RPM but it is not consistent or pronounced. Main problem is the idle, just like yours.

 

same issue but mine was leaking from the valve cover upon a smoke test

 

Do you know if the error will still show up if the PCV is unhooked? The port to my intake manifold is blocked by a BSH boost tap (or whatever it is called) and I unhooked the other side (just for testing purposes!) that goes in to the turbo inlet and of course plugged the port on the turbo inlet (left the hose from the catch can open). I still had the same issue with rough idle. It won't surprise me if the valve cover is bad but I want to avoid spending $350 on a new one and then be wrong. Maybe I can smoke test it also. Are you guys bringing it somewhere to do this or have you made something up at home or own a machine? I've heard they are pretty expensive.

 

Mine turned out to be a dead VANOS unit. It has been replaced and is finally running great! I NEVER would have found that

 

I have the same code 2B64 and misfiring in all cylinders. have already checked intake for leakages, changed all air ( temp and pressure sensors ), throttle body, camshaft sensor, vanos unit, have a new vanos solenoid ... and still the same issue. The car has really rough idle , some cases actually stalls, with higher rpm 2000-4000rpm runs better but still misfiring.
I have checked pressure on fuel rail and is ok 50bars. Timing is good. I don't know what else to do, any suggestion please?

 

Did you check the pressure of the cylinders?

 

yes compression is great 150-160 as well leakage test on each cylinder 1-3%.
Today I was able to experience something very interesting. I decided to check timing again and for coincidence exhaust cam was exactly on time ( engraving pointing up ) but intake was out ~20-30 degrees ( clockwise looking engine from 1st cylinder ) what I found weird. Then I locked the exhaust cam & crank and try to rotate the intake cam ( by hexagon shape on back of it ) - it was possible to move the same 20-30 degree back and make the engraving point up what makes engine match perfectly timing. During this I notice some oil coming out from the vanos ( between can and vanos ).
By doing this looks like I "empty" the vanos from oil. After that I tried to rotate vanos on the other side w/o success.
My question is : should be the vanos on zero position or full position before timing the engine? How to do that?

 

Before you go throught the trouble, you need to take the vanos out and clean it. It will get out of timing again. It happened to me twice on the same car until I replaced the vanos. PM me to give you more directions if you need to set the timing, my easy way :-)