Narvarr Posted April 27, 2020 Report Share Posted April 27, 2020 I have an R53 Mini Cooper with the MiniLink PnP ECU. I have recently been made aware that the ECU does not hold power like the stock ECU. This was helpful during the summer because it allowed the engine cooling fan to stay running for a while when the engine was shut off if the ECT was too high. How would I go about getting that working again? I assume since it was a factory feature, it's just a matter of setting up the correct inputs and turning on the Hold power function. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted April 27, 2020 Report Share Posted April 27, 2020 Looks like the main relay is controlled by some circuitry on the bottom board of the ECU, not explicitly by an ECU output. It or the wiring could most likely be modified to allow the ECU to hold itself on. An alternative could be to have a kill switch to turn off the engine without turning the ECU off (RPM Zero timeout fan setting will need to be set appropriately). Quote Link to comment Share on other sites More sharing options...
Narvarr Posted April 27, 2020 Author Report Share Posted April 27, 2020 Any ideas on what the main relay could be controlled by? The kill switch would work but not really practical on a daily driver type vehicle. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted April 27, 2020 Report Share Posted April 27, 2020 It looks like the ign switch signal comes in on pin 118 as a 12v when on signal and the ecu pulls pin 97 to ground to turn on the main relay. If the main relay does indeed power the engine, fans and ECU then what you would need to do is hook up pin 118 to a DI (set to ignition sw) and to ecu pin 120 (ECU power), this will also require a diode to ensure that only the ECU is powered up by the ign switch and not the rest of the items connected to the same circuit. You will also need to connect a spare inj or ign pin to pin 97 and use it as your hold power output (you probably can't use an aux as if the other side of the relay coil is constant power this could hold the ECU power on). This is all assuming that the other side of the main relay coil is connected to constant power and not a switched power. The help manual "Wiring Information > Power and Ground Wiring > ECU Hold Power Wiring" section might help explain the general idea better Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2020 Report Share Posted April 27, 2020 Im not sure I would recommend changing this as it is likely to open a big can of worms with backfeeds etc. How is leaving the fan running going to cool the engine? - or do they have an electric water pump too? Quote Link to comment Share on other sites More sharing options...
Narvarr Posted April 27, 2020 Author Report Share Posted April 27, 2020 20 minutes ago, Adamw said: Im not sure I would recommend changing this as it is likely to open a big can of worms with backfeeds etc. How is leaving the fan running going to cool the engine? - or do they have an electric water pump too? The upgrade supercharger kit from Harrop comes with an electric water pump. It keeps the pump running for a couple minutes after the ignition is turned off. Someone happened to notice that this doesn't work anymore after switching from the stock ECU to the Link G4+. The switched power for the pump is actually pulled from the cooling fan circuit. Quote Link to comment Share on other sites More sharing options...
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