lambda unit bad
 

Hi, I have bought a 911 sc 1980 which have been standing still for 1 year. Car is starting fine but is popping true intake as soon as you hit the gaspedal. Think the lambda unit is bad and so running lean. When engine is running and I disconnect the relay nothing happens. I have tested the 35 pin lambda connector on pin 8 and 15 for 12v, this is fine. Pin 5 and 16 have a ground. When engine is running and I ground pin 15 it is running richer/faster. So frequency valve must be working.

I really do not know how a frequency valve is sounding but there should be a difference with a disconnected O2 relay? So that is why I am suspecting the lambda unit itself. O2 sensor itself is disconnected.

Please advice how to troubleshoot the lambda unit

The usual fault is the relay next to the Lambda box. It acts like a bad warm up regulator.
The relay is available at auto stores.
Bruce