The ignition coil management seems to be a different part of the software from the fuel cutoff, since we do get ignition spark, at least for a little while, but don't get fuel pressure. So we just stuck a very thin sewing pin through that wire near where it goes into the ECU connector. Then we connected a incandescent bulb based trouble light, with its loose lead grounded, to represent a modest load to that relay coil. Using a high impedance meter to watch that wire, we saw about 4V at that point with the ignition switch on, meaning there is +12V - 4V = 8.5V across the ASD relay's coil. That was enough to turn it on, and the fuel pump turned on.

So we are still trying to figure out WHY does the ECU want to shut off the ASD relay. There has to be a diagnostic chain out there someplace, we just haven't found it yet.

 

How'd the CPS test out?

 

In my mind there's no reason why that wire isn't 12V at that point. Perhaps there is break somewhere between the relay and up to and including the 51 pin on the ECU connector.

 

Or from the ignition to the relay. Or the connectors at the relay.

 

Or the ignition switch itself.