BMW 3.5 BAR 2D2E FAULT

[KnighTT]

Here is the diagram from Vargus I updated. You need to add a check valve that prevents vacuum through the high side catch can and you need an adjustable vacuum relief valve added to the valve cover or crankcase access port. There is one on the front of the head for instance.

Once you put all of this in you need to check vacuum in two places.
1. Intake manifold needs to be within the std 18-22 in/Hg. You can hook up a $15 vacuum gauge to the BOV line. Mine now sits at 20 in/Hg and resolved all my AFR issues.
2. Crankcase vacuum. Mine right now is sitting at 3 in/Hg and that keeps air from being pulled through the main seals, which you will HEAR if that happens.

The 10-14" of vacuum VTT mentions on their valve, I don't know how you'd even get it up that high without all of your engine seals sucking in air. Stock vacuum for instance is around 0.5 in/Hg so 10-14 is incredibly higher than stock. Anything over 4 in/Hg and my rear main seal starts to whistle and ALL of my engine seals are brand new and OE. With the right intake and crankcase vacuum, the car will feel healthy. You'll notice the difference.

Let me know if you have any other questions.

 

[ShocknAwe]

Appreciate this, I suspect this is my issue as well just got my vac tester in actually

 

[BoostN.54]

Here is the diagram from Vargus I updated. You need to add a check valve that prevents vacuum through the high side catch can and you need an adjustable vacuum relief valve added to the valve cover or crankcase access port. There is one on the front of the head for instance.

View attachment 79799

Once you put all of this in you need to check vacuum in two places.
1. Intake manifold needs to be within the std 18-22 in/Hg. You can hook up a $15 vacuum gauge to the BOV line. Mine now sits at 20 in/Hg and resolved all my AFR issues.
2. Crankcase vacuum. Mine right now is sitting at 3 in/Hg and that keeps air from being pulled through the main seals, which you will HEAR if that happens.

The 10-14" of vacuum VTT mentions on their valve, I don't know how you'd even get it up that high without all of your engine seals sucking in air. Stock vacuum for instance is around 0.5 in/Hg so 10-14 is incredibly higher than stock. Anything over 4 in/Hg and my rear main seal starts to whistle and ALL of my engine seals are brand new and OE. With the right intake and crankcase vacuum, the car will feel healthy. You'll notice the difference.

Let me know if you have any other questions.

I have a stock valve cover. The front port for the vacuum relief is the one of the right corner correct?

 

[ShocknAwe]

I have a stock valve cover. The front port for the vacuum relief is the one of the right corner correct?

There's a threaded port on the head in about that location.

 

[KnighTT]

For those with a stock valve cover, it can get complex.

In a nutshell, for anyone modifying the PCV system or valve cover, "What you take away must be replaced". If you remove the factory PCV valve you need to replace its function in some way. Same thing with the flapper valve, which is a check valve with a metered vacuum relief(in the form of a small hole). You can't ultimately delete either of these without their function being performed elsewhere.

- If you remove the PCV valve to route a catch can on the low side, that pulls from the throttle body, you still need a PCV valve of some sort. This can be done with a vacuum relief valve. You also need a check valve on the low side after the catch can but before the throttle body to keep boost from leaking up through the low side lines.
- If you delete the high side flapper valve - The high side needs a check valve just after the valve cover, before the catch can, as this let's boost pressure past but is closed 90% of the time preventing vacuum from pulling through and messing with your crankcase vacuum.

*NOTE*. If you add a low side catch can, wish is pulling vacuum from your throttle body, you are now pulling vacuum from both the holes in the head that are in the intake ports AND the throttle body. Side note, meaning not all of the gasses you want filtered in your catch can are going to your catch can. This will also most likely lead to excess vacuum. This is where you'll have to put in a vacuum relief valve and dial it back down. Best bet here would be to block off the head ports so the vacuum is only coming from the catch can line and then use the vacuum relief valve to set the vacuum you want in the crankcase.

Also, check your intake manifold vacuum through the BOV line to verify your modifications have not caused an issue that will set off a 2D2E and mess with your AFRs.

This is what healthy looks like for my setup and what got rid of my 2D2E and excessive crankcase vacuum.
Left is intake manifold vacuum - -20 in/Hg. Right is a manometer for crankcase vacuum. -3 in/Hg.

 

[ShocknAwe]

Measured my TB vac at -18, is there a cap I can buy to measure crankcase?

If I open the oil cap it just feels loose no pressure or vacuum whatsoever.

 

[KnighTT]

One of the easiest things most people do is buy a cheap extra oil cap. Drill it out and install a 1/8" barb connector and then hook that up to a vac guage.

 

[MoreBoost]

I now have this beautiful problem too.
Will try to figure out the solution tomorrow.
Car has been stalling on hill starts and it's DCT

 

[steve30]

I now have this beautiful problem too.
Will try to figure out the solution tomorrow.
Car has been stalling on hill starts and it's DCT

This code just popped up for me the other day as well. I was also getting 2CF7 and 2CF6. The car never stalled but the idle was roaming up and down. I removed the MAP sensor (on the intake manifold) gave it a clean and it hasn't shown up again. I also reset most of the adaptations with MHD and throttle adaptation was reset using the pedal method. I would give that a try and also check for a vacuum/boost leak on the charge pipe.

 

[MoreBoost]

This code just popped up for me the other day as well. I was also getting 2CF7 and 2CF6. The car never stalled but the idle was roaming up and down. I removed the MAP sensor (on the intake manifold) gave it a clean and it hasn't shown up again. I also reset most of the adaptations with MHD and throttle adaptation was reset using the pedal method. I would give that a try and also check for a vacuum/boost leak on the charge pipe.

Will do thanks.
Been having some strange issues lately possibly all vacuum related.
Vacuum lines all seem good but wastegates are rattling like mad. They sound like they are fully open at times and lots of smoke.
This mixed in with the throttle and tmap codes. Great!