New to me 82 auto trans running rich

[SBL]

Hi all:

Well I could not keep out of it for long. Picked up a 1982 automatic. Ran poorly with a lot of bogging. I reasoned that it was running too rich and probably not in closed loop. Worked on wiring and hoses, and then had to turn CO screw a half turn CCW and to get it to run reasonably well. I have always had manual Deloreans, so I don't know how it is supposed to run, but so far it has reasonable power even with AC on from a dead stop (which it did not have before) so I feel I am headed in the right direction.

Here are my tests of frequency valve duty cycle (actually dwell method, 8 cylinder setting, data shown is multiplied by 2) :

cold 52 stable
warm 40-60 varying
warm O2 sensor disconnected 54 stable
warm O2 sensor input to ECU grounded 80 stable
warm O2 sensor input to ECU +1.5 VDC 32 stable
warm WOT switch engaged 60 stable

When driving, WOT second gear kick-down works.
Idle 750-800.

To me, I think I am still a bit too rich. Agree?

steve

[Ron]

1/2 turn is a lot, but it looks like you might be good if you set it to 40° (+/- ~5° swing).
Don't forget to plug the adjustment hole when reading...

P.S. Congrats!!

[DMC-81]

Congrats Steve!

[David T]

You want to aim for 35-45 dwell but if you have vacuum leaks you will still be running rich. Adjusting the mixture screw is the very last thing you do after fixing any vacuum leaks, cleaning the injectors, and changing the spark plugs and filters. Also check the timing and ignition advance. Depending on the mileage you might have to change the O2 sensor and adjust the valves.