I have better fingers here late at night....:nanana:

I have not wrenched on a 2005 or 2006. I can just point to realoem

As to the other question, I disagree on this - my secondary are pump draws air from the clean side of the air filter box, not open air (this is the stock configuration). So, if something fails and the exhaust gas goes back into the air pump as we seem to agree, where can it exit the system? On mine, it is into the air filter box which creates the "short circuit" into the primary air intake and then the MAF and so on.

It's darn hard to navigate realoem on an iPhone!!!

The change in late 2003/2004 appears to bring a totally electric air switch, no secondary air switch. Interesting......

Still can fail and allow the higher pressure exhaust gases to go into the air injection system. Hot Hot HOT!!!!:scared:

Dave
You are correct, on the 4.4 engines the engine air box is part of the air pump system. On his 3.0 it appears not to be.

Yeah sorry about that Dave, I have not looked at the layout on the V8s.

This is the layout on 2004-2006 x5 3.0

http://www.realoem.com/bmw/enUS/show...diagId=11_3566

I replaced items 6, 8, 10, 11, 14, and 12.

So were all on the same page, the pump did kick on today (afternoon) for a full minute, so at the moment I believe the problem has been solved.

I am still wondering why it did not kick on this morning. It kicked on this afternoon while getting lunch. The car should have been in a colder state this morning rather than this afternoon.

If the air injection system fails and owners ignore it, sooner or later on the ones connected (that draw fresh air supply from the engine air box) will burn up all the way to the throttle body.....

Ask my why I know....I purchased one like that years ago. It took out the cat too! Never saw a melted air box before and hoses were all soft and stringy. The PO just drove on until it failed emissions testing.

Cheap buy going in, a very long path to fix everything.

Wow! I'm glad that isn't the case for me. Worst case scenario my pump is on its way out but with my configuration, since the system is isolated no other components are in harms way. The valve will prevent exhaust from going to the air pump (closes after a minute on cold starts).