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Vr4link AUX-Injector 6 output

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Im in the middle of building a totally new harness for my VR4 with the VR4LINK.  I have run out of AUX outputs and wanting to use the Injector 6 output.  In the wiring information it mention the output being used for 'ecu hold power' but can not find any information on the pin used for this . 

Im wanting to use this to run my engine fans..

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Injector 6 controls the main efi relay.  This is done because the car has a stepper motor idle valve, so after you turn the ignition off, the ECU needs to stay alive for a short time to reset the stepper motor.  Injector 6 is what keeps the main relay engaged.

Unfortunately you cant use Inj 6 for anything else as it has an additional circuit connected to it internally to make the relay control properly.  

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Thats great to know. I did suspect something like that as I could not find any info. So it must use either pin 56 or 66 . Ill have to check the mpi relay diagram..Im not using the factory relay any more as I have a custom relay setup. I can just find the pin and wire it to the new relay for the isc to keep it active to reset . Ill just wire fans to the AC trig. 

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I have a couple other questions also. I have removed the power transistor for the factory coils as im going to run a direct fire coil on plug system , so I have lost the factory tacho output and was told to run a relay triggered by ecu ( with contacts removed ) parallel to an Aux output set for tacho to create the voltage needed to drive factory tacho. Do i need to run a resistor inline to the relay coil ground? 

Also , the AUX settings have a high and low setting . Is this to change between a pos and neg trigger? 

 

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11 hours ago, ozyvr4 said:

So it must use either pin 56 or 66

Inj6 grounds pin 63 & 66 to power up the mpi relay and associated circuit.

 

8 hours ago, ozyvr4 said:

Also , the AUX settings have a high and low setting . Is this to change between a pos and neg trigger? 

 

The high/low polarity settings on aux outputs is to invert the behaviour.  Polarity low will output a ground when on.  Polarity high will be grounded when off.  On some auxes you will also have a highside/lowside drive setting, this is irrelevant on the VR4 ecu as it only has lowside drives fitted.

 

8 hours ago, ozyvr4 said:

I have a couple other questions also. I have removed the power transistor for the factory coils as im going to run a direct fire coil on plug system , so I have lost the factory tacho output and was told to run a relay triggered by ecu ( with contacts removed ) parallel to an Aux output set for tacho to create the voltage needed to drive factory tacho. Do i need to run a resistor inline to the relay coil ground? 

If you have a spare injector or ignition drive to drive the relay then it will work without anything extra, just connect the relay coil parrallel to the tacho.  If you only have an auxiliary output then you may find the flyback diode will prevent the relay from doing its job, you will have to use an extra transistor like the circuit you will find all over the net in this case.

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Thanks that some great insite to how it all works. I went over the mpi relay schematics and saw how it works. I will keep it as normal on inj 6 and swap my fuel pump to an AUX trig and use the injec 5 for the tacho. At the moment the AC does not work so ill use that output to drive fans. 

 

Ive added some pics of the harness and the coil setup as this is totally different than a stock setup. 

20190323_005349.jpg

20190331_230842.jpg

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