Now a knock problem...

[84GNwith87eng]

Ok...start car up, idles at 2000 rpms....Scanmaster shows 13.4 degees knock on startup, then eventually goes to 0, 02's stay at 941....

I can't build any boost to the turbocharger....what would you expect has failed on the car?

 

[soundguy]

how soon after startup? It may just be picking up the vibrations from the starter turning the flywheel.
What circumstances around not building boost? While cruising? Power braking? In park?