Tracked an intermittent idle quality issue to timing. Timing appears to be hovering around 16-18 degrees and wavers. Occasionally when warm/hot the timing will jump up to the 'normal' 20-22 degrees and stay rock steady. After checking and testing new components from the ESC to the KS, I've done the following:

confirmed 9+ volts out of the ESC module on Pin C.
confirmed continuity from Pin C on the ESC connector to Pin L on the ECM
12 volt test light to ESC connector Pin C or Pin L on ECM, no change-no light
10 K ohm resistor across ALDL A and B results in smooth idle with 20-22 steady advance (I've read this disables the ECM's retard function).

Shop manual flow chart says if 12 volt light to Pin C doesn't work: loose connection/bad ecm. Replaced ecm with another 87 LG4 and no luck.

Is there a ground or other connection at ecm that could be at fault?

I struggled with hooking up WinALDL for a time, read up on some troubleshooting and saw a thread where it would work with the LG4 ecm but wouldn't read knock counts. My enthusiasm waned.

 

Not even some words of encouragement? sheesh.

 

I usually wait until naf comes in to answer these types of questions. . .