Easy to find? Well, it is the only hole in the top of the air cleaner
. That hole allows adjustments to be made with the sytem properly closed.
If you remove your air cleaner you will see the tower, it is between the fuel distributor and the throttle body. If you cannot insert a long allen (or suitable probe) into the end of the tower, then it is plugged (should go in about 1.5-2 inches if unplugged). Two types of plugs have been used, one a small cylinder, the other a ball bearing. According to the manual, the plug is drilled out for corrective adjustmeents, then a new plug is inserted. In most cases, if an adjustment has been made the plug is not replaced.The hole in the air cleaner is accurate for US models, not sure if Euros are set up the same.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.