EFI electrical issue

Hello All

My beloved van won't start and I can't work out why, so I'm posting to see if anyone can help...

The problem with my van appears to be something to do with the power supply to the ECU. This power supply also feeds the fuel pump and injectors. For some reason when the ignition is turned on, the power supply to the ECU reduces from 12v to about 2v, suggesting there is a short somewhere.
The fuses are ok, and the “EFI” relay seems to also be operating correctly.

Part of this circuit should also power the radio, but the circuit diagram I have does not go into detail.

There does seem to be a lot of ‘bodge’ jobs done to the wiring loom underneath the dash, but again, I can't diagnose any further as the wiring diagram I have doesn’t match the vehicle.

Any bright ideas/suggestions are welcome (including recommendations for any garages in the Rugby area who know about Daihatsus...)
Thanks

Welcome in a drop in voltage could be a connection going high resistance try the wiggle test with the loom see if it changes and also try wiggling the key about incase it is a worn switch.

I think you should have a look at this thread:-

https://hijet.forumotion.com/t735-electric-avenue

Sounds like either you boot battery wire is dodgy, your main relay is dodgy or maybe something in between.

First one to check is that blasted battery connector - all of you electrics excluding the starter motor are powered of the thin wire on the battery +12v terminal, thing is the connector always goes dodgy and often will fall out if you pull them.

The problem seems to be fixed now. It was the ECU power wire from the battery as you suggested.
Thanks for your help!