ECU Hold power - engine not switching off (SOLVED)

[beninnz]

Finally got the engine running (see other thread here) and now I'm chasing down the next gremlin  

I've set up the ECU for Hold Power so that I can run the radiator fans and electric water pump after engine shutdown if needed (to protect the cylinder head). 

I thought I'd followed the guide correctly (G4X Scheme 2) but I've obviously done something wrong as the engine won't switch off - it keeps running until I pull the fuel pump connector. When I'd been testing the hold power functionality before I had the engine running it worked fine - ECU shut down 15s after switch off.

ECU Hold Power settings in ECU:

Output: Aux 8
Aux 8 Active State: Low
Aux 8 Driver Type: Low Side
Keep Alive Time: 15s
Kill Until Stalled: No

Attached is a drawing I've done of my wiring set up for the main power / relays. Would be great if someone was able to point out where I've gone wrong  

 

Edited December 22, 2023 by beninnz
Solved issue

[beninnz]

Replying to myself, realised I'd missed out the radiator fan relays which are in a separate 'multi function relay unit' (MFRU) in the front of the car. Have updated diagram and attached below. The relay unit enables the fans to run either in series (half speed) or in parallel (full speed). The relays are triggered using 2x spare ignition outputs on my ECU.
I originally had these triggered of AUX outputs but couldn't get the ECU Hold Power to work (prior to getting the engine running). Once I switched them over to spare IGN outputs it seemed to work (at least in my testing before I had the engine running). 
 

I'll try running the car and switching it off with the 2 radiator fan relay pins disconnected from the ECU tomorrow morning to see if I can isolate the problem. 

[Adamw]

The Ign Sw function will cut all fuel and spark when the signal on DI2 goes off, so you must have something else connected to the ignition switch circuit that is keeping it high.  Possibly the alternator lamp?  Provided those fan relays are connected to ignition drives I dont see any way they could cause it.

[beninnz]

13 hours ago, Adamw said:

The Ign Sw function will cut all fuel and spark when the signal on DI2 goes off, so you must have something else connected to the ignition switch circuit that is keeping it high.  Possibly the alternator lamp?  Provided those fan relays are connected to ignition drives I dont see any way they could cause it.

Thanks for the pointers Adam. You were right that something was keeping the ignition switch high. It wasn't the alternator light though, it was the missing front clam & disconnected headlights... as soon as I plugged in the front right headlight the engine happily switched off!

I knew it'd be something simple. So thanks for the pointers.

Am still a bit confused as to why the ECU Hold Power 'state' shows as 'Active' when the engine is running though as the Help guide suggests that it should show as 'Inactive' when the engine is running. But either way it seems to be working as intended now.

Cheers, Ben