Duty Cycle 1980 slc
 

I've been reading alot of posts on the duty cycle but most appear to be for 1985 and later cars. My 1980 was the first year for lambda system.

I purchased a Sears dmm with duty cycle. The CD say's connect "voltmeter" with black lead to pin 3 and red to 12 volt source.

Most of the posts I've read say to connect red to pin 3 and black to pin 2. This is the way I proceeded, and couldn't get the % any lower than 632 before stalling.

On an early model 107's using a duty cycle dmm which way should I connect the red/black leads? Black on pin 2 / red on 12v, or red on pin 2 black on pin 3?

That car & all V-8' upto 1986 don't use a standard duty cycle signal.

That signal from the computer is actually a Hz frequency. We used a special "LAMDA" box to set-up that fuel mixture.

You can measure the O2 voltage & set the mixture by splitting that signal into half's.

From where can I measure that voltage? Can i measue it from the diagnostic socket pin 3? Thanks

Needs to be measured at the O2 sensor OR at the computer. Measure dynamically, with the system operating in closed loop.