I'm looking at diagnosing problems with a L-Jetronic system

[Victor Tomanov]

The ECU that controls my system doesn't have a diagnostic capacity. I'm
at a loss at how to figure out if the ECU is running the motor correctly
and if the mixture is realy what it should be. It seems rich. I'm
looking for a way to modify the lean rich mixture variable either by
taping into one of the sensors or adding a pot to the ECU. Does anyone
have a working knowledge of this injecting system?
Thanks for any help.