> The ground points up front ARE a pain, I've got one of them (on drivers side) clean but the other is way under and I can barely see it let alone touch it!!! Does any one know for sure if this is the ground point for one side of the injectors or not??
> I know I should have the injectors rebuilt and I was planning on it (even have the rebuild kit ) until only the injectors on one side weren't clicking, then my electrical gremlins side of my brain got working overtime thinking that there might be an easier way out of this mess since nothing was leaking etc.
> Anyway thanks for the input,................. anyone else??
> Walt L
> '82 5-speed
For a '82 model !!
The injectors do not ground on the engine or the chassis.
Power is supplied to your injectors thru Relay XVI. Power flows from the 87 terminal of the relay behind the panel to terminal W2 and W3.
Plug W is the next-to-last plug on the right end on the bottom of the Central Electric Panel. The terminal are arranged:
From W2, power flows on red/black wires to the injectors for cylinders 1, 5, 2 and 6.
From W3, power flows on red/green wires to the injectors for cylinders 3, 7, 4 and 8.
From cylinders 1 and 5, power flows on gray wires to terminal 15 on the injection ECU.
From cylinders 2 and 6, power flows on gray/black wires to terminal 33 on the injection ECU.
From cylinders 3 and 7, power flows on gray/green wires to terminal 32 on the injection ECU.
From cylinders 4 and 8, power flows on gray/red wires to terminal 14 on the injection ECU.
The only single points that would cause half of the injectors to not function are W2 and W3, or the connections to them behind the panel.
All of this info is on the CDs that Jim Morehouse sells. His email is jim928ATptd.net - change AT to @.
For a 1988 928s4 its like this:
Power feeds from the battery directly onto U12 and to LH-Relay XXV terminal 10. When engaged, the relay will provide power to relay terminal 87 which feeds to W13.
From W13 onwards power is split into two stages:
One provides +12v power to link-point  which connects injector pin 2 at cylinders 1,2,3,4 and the other goes to link-point  which feeds pin 2 of the injectors at cylinder 5,6,7,8.
Power return flows from injector pin 1 at cylinder 1,2,3,4 to link-point  and pin 1 at injector cylinder 5,6,7,8 to link-point 
Both link-points  and  are connected on the LH module at pin 18, which will trigger injection pulses by switching the signal at pin 18 to ground. All injectors are fired simultaneously whenever the system is running.
As you can see, its very simple, and a bit different from a '82 model.