As said before, we have a supercharged AU xr8, and it doesnt want to start. We can hot wire the car (fuel pump and starter relays) to start it, but all of the warning lights stay on (but the oil pressure comes up on the guage), and the tacho doesnt move.

The computer is the standard ford computer, running a haltech as a piggyback.

As a side note, the relays have power and signal to them (ie get 'switching' power) when the appropriate button/knob/switch is pressed, but dont appear to have an earth. However other relays on the same bank (ie horn, lights etc) seem to work fine, but when put into the starter/fuel pump slots, nothing happens.

This is a sudden problem (ie car didnt just stall and refuse to switch off, the car just got parked, then refused to do a thing).

thanks
Ben

Sounds like a smartlock/smartshield problem...the body module may have gone south on you.
You won't see anything on the ground side of certain relays because they are low side driven ie; the ground is switched by the EEC.
Do a self test.

Pete.

yeah, we cant see a ground for the signal side of the fuel pump and starter relays. But we can still run things like the stereo, elec windows, central locking, etc.

however we do get a signal on the signal side of the switch (ie test light lights up on some terminals when starter motor and fuel pump are SUPPOSED to go on), just no ground on those two, and no guages.

thanks
Ben

Yep, that's because the fuel pump and starter relays are low side driven and disabled via Smartlock or smartshield...whichever your vehicle has. I believe smartlock was on AU1's but don't know the cutoff date for smartshield changeover. The Gauges are also driven by serial data from the EEC which if disabled will of course not work.

Pete.

My AU1 has Smartshield. Its a 10/99 build.

so the relays are driven on the power side by the ignition, and ground side by the computers?

Check all fuses..As Pete said "smartshield"...