I remembered to put the meter in the car last night. Measuring the DC voltage at pin #3 will not give you a meaningful indication. It needs to be set for 50% duty cycle.
You need to read the Steve Brotherton article about this in the DIY and maybe do a search on lambda adjustment. There was a good thread about this by Donnie a couple of years ago.
I have a customer in house today and will probably be out to lunch with her, but let me know when you would like to pick up the meter and I will try to have it ready for you.