High Idle on start

[Vic]

Hey guys

Wondering if anyone could help me on my 323i, it revs very high after starting. It starts beautifully and idles well but then after 10-12seconds it shoots upto around 3k and stays there. I’ve checked for vacuum leaks and none are obvious however will be triple checking tomorrow. I’ve removed and tested the additional air slide, and that’s working fine; opening on cold and closing upon heated.

Does anyone have any experience they could kindly share regarding this issue or some tips on resolving just want to finally get the car to the mot garag

I’d be grateful for any input!

[Jeroen]

And if you adjust the idle downwards using the brass screw on top of the throttle body? Just count how many turns you adjusted it, try a cold start and see if it still catches on. Only do this after you've verified all vacuum connections are ok including those of vacuum ignition advance and after making sure the throttle body closes correctly, and the same for the piston on the fuel distributor (arm moving freely and moving back to base position, check inside air box or under the big rubber boot). More details on this in the FAQ section.

[cobbler2u]

Ive got similar problem and found fault to be the auxiliary air valve
bought mine from main dealer
This is part on wallothnesch.com
A11531288029

There is a used one in (for sale section) parts for sale 323i