[s-cars] CPS Question

[racingiron at comcast.net]

> Pin 30 on the ECU connector is shown on the Bentley diagram as going 
> directly to ground, but I'm not getting that. Specifically, it's #201, which 
> Bentley calls "ground connection -5-, in engine compartment wiring 
> harness." 

Can anyone give me a clue about where to find the ECU ground point? I'm fairly certain it's the source of my problems (well, THIS problem, anyway!) 

Eric R. 
'86 urq 
'92 urS 
'93 urS