So, I took my new Sears DMM with Duty Cycle into the garage and made my first attempts at diagnosing my symptoms of low pwr, rich mixture, hard cold starting. Here is what I found so far:

Pin #3 Test

1) key off = 0%

2) key on, engine off
Initially = 94.6%, then I heard a noise near the valve cover (like a relay moving to a new position) and the duty cycle immediately dropped to 14.9%

3) engine on
This is where things got strange. Duty cycle was all over the place, but no matter how big the swings, it quickly tended to 0%. I kept moving the ground connection of the DMM to other points on the car, and then I'd get another reading for a few seconds and then it would tend to 0% again. I was unable to get readings for more than a few seconds without playing with the ground lead for the DMM.

I tried adjusting the lamba tower, but I didn't take much of a turn before the car died, and the DMM duty cycle still tended to 0%.

I unplugged the connector from the eha to see if this made a difference. The engine check light did come on, but I was still unable to get any duty cycle readings. Unfortunately, I do not yet have an EHA harness, so I was unable to test the EHA.

Can anyone shed any light on why my duty cycle is quickly moving to 0%?

Thank you in advance.

__________________
Steven
1989 260E (276K miles)
1995 E320 (50K miles)