Hello everyone,
I'm trying to track down a problem and I keep coming up with nothing. I have a rough idle and have been getting error 2B64 (unmetered air in intake manifold).

What I would like is if some people could share some values that they are getting at idle with a stock, at least not tuned, MCS. Examples of what I would like are:
*throttle position
*manifold pressure
*ignition timing
*mass air flow
*fuel flow

I have checked for leaks and any found were fixed but I keep getting the code. I even sealed the intake manifold off of the car and tested it for leaks, both with pressure and vacuum.

A bit of background, I burned an exhaust valve some time ago and rebuilt the head and did some mild porting and I've been having this rough idle ever since I got it back together. The valves all sealed great before I reassembled the engine. Above 2000 RPM or so and it seems to run mostly fine.

Thanks for any and all help!
Howard

 

Any insight would be valuable!

Let me ask this, if the valve cover was cracked, would it still cause an error if the PCV wasn't hooked up at all? And of course where it connects to the intake tract were plugged. It doesn't seem like it would.

 

I can get you some numbers later today when I get home but what exactly do you mean by "PCV wasn't hooked up at all"?

If you mean to just run draft tubes like in the old days then yes you will probably get a CEL.

If you mean to plug all connections and not vent the crankcase then you'll obviously have other issues, like blowing out gaskets and seals.

 

Cerenkov,
Thanks, I look forward to seeing them! I'm quite tired of working on this thing :(

To answer your question, I have a BSH catch can but last night I unhooked it from the turbo inlet and plugged the connection at the turbo inlet, so no intake side leak. The hose from the catch can/PCV was left open to atmosphere. I DO NOT plan on driving like this, I just wanted to see if that solved the rough idling problem, which it did not. The side that goes to the intake manifold is already plugged with a BSH boost tap (I might change this once I get this problem fixed, I'd like PCV both with and without boost).

 

Can anyone answer my question about a bad PCV in the valve cover? If the port going to the intake manifold is blocked, will you still get a code 2B64? Or a rough idle due to the bad PCV?

I know I have seen several people describe 2B64 as a leak in the intake manifold (after the throttle body) or PCV. Is that the case or is it just air that is not metered by the MAF sensor immediately after the air filter? Meaning 2B64 could be a leak anywhere within the intake tract.

I don't want to start throwing $400/ea parts at this car hoping that I guess right. If something is broken (PCV, throttle body, MAF?) I don't mind replacing it but I want to know it is bad before I replace it and I don't know of anyone around here that has a MINI that I oculd swap parts from :(

 

Here's a graph of a data log that I took tonight. I switched to the stock maps this is NOT the Manic maps. The car is fully warmed up.

 

looks like I have both less mass air flow and less manifold vacuum, sounds like a legitimate leak and not a bad throttle body or MAF sensor. Could still be the valve cover, maybe. Thank you cerenkov, that has eliminated two possible faulty components!

 

Huh...I must have made a conversion error the first time, or remembered my MAF wrong. I am getting 1lb/min air. Still almost no vacuum (3in-Hg) and very retarded ignition timing (between zero and 12 deg ATDC). Not really sure what is going on :( I think my next step will be to make sure I don't have the wastegate too far closed or something, I did have it apart. The leaks I have found have been fixed, the camshaft timing is good and so is the "lash" (I can move the followers on all 16 valves when they are not open). Certainly wont rule out a leak but I can't find any more. I've had the PCV blocked and it didn't seem to affect the values but I want to check that again too. Oi, I want to be done and drive this thing again!

 

These crazy cars. It turned out to be my VANOS unit! The dealer said that this is pretty common but I don't recall seeing anyone post anything about that. It has been replaced and is finally running great!

 

I have the same problem Howie. Pulling 2B64 "suction tube".
From what I gather this most likely means the VANOS solenoid valve
isn't operating properly. I am getting a slight stumble at idle and will
eventually pull a 2B64 engine code after driving around for a few hours.
So I take it that the solenoid is failing and allowing air to blow by when it shouldn't and of course the VANOS solenoid has a sensor on one side that I'm guess is triggering the code by sensing improper values.

How much did the mechanic/dealership charge for the part
and for labor?

I believe this is an easy DIY. Just pull and replace.

I see a few others are getting the 2B64 code so I would like to follow-up on this and prove it is the VANOS solenoid on my car as well.

 

If it is just the solenoid valve then it is straight forward: unplug, remove bolt and pull out. It might even be worth removing, cleaning and reinstalling. If you have the N18 which is dual VANOS then you can swap the intake and exhaust units to help troubleshoot.

 

Hey Timski, I think maybe you had a comment on another thread I had commented on as well. Often times, this code is from a leak. The description I have for it is "unmetered air in the intake manifold" or "leak downstream of throttle". So the first step is to check for leaks! If you can't find any, then maybe just change the solenoid. That is simple, it is right next to the timing chain tensioner. Part is available several places for about $120 but I did see a Dorman branded one that looked like it was only $80 or something, I think that was at Summitracing or maybe Rockauto. It is hard to get out of the head, I had to use a channellock pliers to get mine out, I think. The dealer did mine, because I had it there.

The VANOS unit itself was $420 (ECS tuning had it the cheapest by far and the dealer matched with shipping). To change it, you need the timing tools to lock the camshaft and crankshaft, plus a new bolt. The labor for that was $300 (kind of high...since it doesn't take too long). The tools are a little less than that, if you want to do it yourself. But please, if you don't trust yourself, don't mess with the timing parts. If they are significantly off you can ruin your engine. It is not difficult, just not very forgiving of mistakes!!


What Cerenkov says is a great idea as well. Free is always preferable You might be able to activate the solenoid off the vehicle to see if it looks like it is working correctly after cleaning it. I don't know if it operates with 12V or 5V. A guy I work with was saying Toyota uses 12V, which is probably the same but most sensors use 5V, I believe, but it isn't a sensor either

 

If the VANOS solenoid is hard to remove then rotate the crank to move the valves a little and it should be easier to get out.

Another culprit to the unmetered air leak downstream of the throttle may be the fuel vapor return line solenoid (not sure what is actually called).

 

We have a VANOS DIY here if needed.

 

cerenkov how did you create the functional graph? My graphs in Scan-XL Pro don't look quite like that, is it possible to import it? Now that's what I'm going to need to view my logs.

I had a hell of a time removing my Vanos solenoid, fought with it for half a day! Had to remove intake manifold to get at it with a flat head screw driver. Lots prying and it finally came loose.

 

I'd be happy to email you a link to download the configuration and/or layout file. Just PM me.