[s-cars] Stalling Solution, Was:CPS Question

[racingiron at comcast.net]

Weather was nice the rest of last week, so I rode the beemer to work and didn't have time to work on the S until yesterday. I set out looking for the mysterious "ground connection 5". No ground spots in the engine bay besides the standard ones on the head, so I started digging under the dash--both sides. No gr/bk ground points under there either. With harness plugged into the ECU, I get continuity to ground from the sensor connections... Great, the wiring diagrams must be wrong! Pin 30 doesn't go to a ground point, it PROVIDES a ground for all the sensors THROUGH the ECU. Connection 5 must be a spot within the harness where all the wires are tied together. 

So, after that wild goose chase, this morning I decided to just button everything up and drive the car until another incident and start troubleshooting again. As I was doing up the driver's side, I found the problem. The nut on the #15 stud on the bottom of the relay panel was loose. Sure enough, this supplies power to the ECU. Removing that connection causes the boost gauge to drop to 0.2. With that nice and tight, I'm sure the car will be fine... until the next issue. Thanks for all the support, guys! 

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