Adamw Posted December 30, 2020 Report Share Posted December 30, 2020 A5 is the main ecu power supply, so you need to fix that. It should have full bat voltage on the A5 pin with ign on, ecu unplugged. Quote Link to comment Share on other sites More sharing options...
h82lose91 Posted December 30, 2020 Author Report Share Posted December 30, 2020 So I figured out once again this patch harness is partially the issue. With it back to stock ecu, fuse 21-22-23 get powered correctly from the MPI relay and voltages in and out of the MPI relay and the fuses match the battery. With the patch harness only connected, Fuses 21-22-23 have power.as well as the MPI relay on the output pin to these fuses with the KEY ON. Voltage does not match battery voltage its less. If i pull Fuse 22, there is now no power on Fuse 21 and 23, and the output leg of the MPI relay is also 0volts as it should be on the output pin. So some how the patch harness is back feeding voltage to the ecu from A5 which is going to Fuse 22, which should be the other way around if im following things correctly. Gave a call to the patch harness manufacturer, he seems to think this is an issue with the ecu hold power configuration and the diode thats on A5 and A23, basically that its not setup/configured correctly. Im not seeing what not setup correctly with the ECU Hold Power. Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 31, 2020 Report Share Posted December 31, 2020 Ok, so I just looked at the wiring diagram for an EvoX and the main relay is controlled by the ecu. The ECU grounds pin 73 to turn on the main relay. So testing voltage on 82 with the ECU unplugged is probably giving you odd results since 73 would not be grounded with the ecu unplugged. Pin 73 is controlled by Ign 5 and that ecu hold power looks set up correct to me. Looking at your log again with the batt voltage spikes, I think it is caused by the odd set up on Aux 7 controlling your alternator. So I dont think there is any issue with your wiring... As soon as batt voltage drops below 12.00V, aux 7 turns on and your batt voltage shoots up to the moon. Im sure I have had other users running evox's without any alternator control needed, but it looks like yours may need something. Can you try turning off aux 7 and see if you get any charging voltage at all. Quote Link to comment Share on other sites More sharing options...
h82lose91 Posted December 31, 2020 Author Report Share Posted December 31, 2020 Log switching AUX7 Off. The voltage instantly climbs until the ecu hits the voltage limit and shuts off. Had to zip the file down. Other log file is aux7 off and the ALT Control wire removed from ECU. Voltage is now stable with the wire depinned from ECU at 14.4v. aux 7 swtiched off.zip aux 7 Alt Control Wire Unplugged from Ecu.zip Quote Link to comment Share on other sites More sharing options...
Adamw Posted December 31, 2020 Report Share Posted December 31, 2020 Yep, looks good with it unplugged, it must need to be floating. Quote Link to comment Share on other sites More sharing options...
h82lose91 Posted January 4, 2021 Author Report Share Posted January 4, 2021 Yeah also this corrected our battery drain. Now the fun can begin! Thank you all for the help! Im sure Ill have more questions. Quote Link to comment Share on other sites More sharing options...
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