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Help - can't locate where this vacuum line behind the alternator is meant to go!

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Hi everyone,

Yesterday started the process to replace my alternator/starter cable (as well as the alternator regulator and drive belt) on my 1999 911 c2 cab. Apart from a plastic coolant connector splitting, everything went pretty well - until I realised there was a random loose vacuum line hanging around behind the alternator - and I can't for the life of me figure out where it's meant to plug into!


Have attached picture to this post.


Stupidly I went ahead to finish up the job, refitting the alternator, drive belt and airbox. Car started up, but with a very rough idle (which I figured was from having the battery disconnected for 2 days) but after it warmed up, there's was a lot of backfiring from the left side bank/left exhaust and running very rich, which I figure is due to that vacuum line not connected properly.


I figure it'd take me maybe 30 minutes to get to that vacuum line again which is fine, I'd just like to know where it goes! Thanks everyone for the help!


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Thanks @DBJoe996 based on that diagram I think it's C - no wonder I couldn't see where it goes, being hidden on the inside of that intake pipe! 

Question - do you think I can plug it back in by removing the intake/throttle body, or am I going to have to get the alternator out again?

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Thanks everyone - problem solved. Got the intake, drive belt and alternator out in 15 minutes, plugged in the loose vacuum line behind the intake, reassembled everything and she's good to go now! Yet to take her for a long drive to see if my charging voltage is stable, and whether my hot start issue is solved, but fingers crossed!

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