325is wont idle.

[ElTonyo69]

I have a 94 325is and just finished tightening down the last bolt after a head gasket replacement and now when after I start it the car immediately sputters then dies. If I apply gas it stays running. It also smells like it is running rich. This problem was not prevalent before the rebuild. I was thinking that perhaps I all of the sudden had a problem with the IAC valve and pulled it out and messed with it. All of the moving parts manipulated completely and smoothly. I was also thinking about some kind of other vacuum leak. All of the hoses are in good condition or were replaced when I have the engine in pieces. I did become frustrated during initial removal of the intake and broke off the clip to the hose that flows from the manifold to the IAC valve. The hose still goes in and seats completely so I don’t think that it is leaking a lot if at all.

[Lord Vader]

Even a super small vacuum leak can cause issues. I would double check that. Since you replaced the head, what about all the vacuum lines? Good thing to do with everything else already out.

Get it scanned for trouble codes and see if anything pops out. Could be a throttle position sensor or CPS thats not in properly or worn out.

[ElTonyo69]

So I replaced the broken piece and it did not help the issue. So I did some more thinking and decided to recheck my work with the VANOS and all of the timing chains and cam shafts. This is where I found my real issue. I was in to much of a hurry the first time and did not go through the motions to properly align all of the sprockets and chains. After installing everything correctly the car purrs like a kitten.