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Luis Lopez

Aux9 not sending signal to fuel pump relay

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Hi guys new here and new to all this programmable ecu stuff. So I have aux9 as my secondary fuel pump but when I went to test on the relay nothing happens. So I swapped the pins on the relay (85-86) and it clicked but it stopped. And he check engine light came on and it said something about temperature. The car is an Evo 8 2003. 

9348E973-2AEC-46E1-8DEA-90B7109F9540.jpeg

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Hi Luis,

With our plug-in ECU's that have Aux 9 & 10 available on the Expansion connector, those outputs were mostly put there with the intent of driving an E-throttle motor.  This next bit is hard to explain, so I will do my best:

There are some shared electronics resources that create odd interactions between Aux 4, Aux 9 & Aux 10.  In our wire-in ECU's most of this interaction is hidden from the end user in the software/hardware so they can freely assign whatever function they want to whatever Aux they want and it will just work.  With our Plug-in ECU's however since they are expected to be connected to a factory loom with many functions already assigned to certain pins, some of this confusing interaction is not able to be hidden (and its not even documented well).  You will notice in the software for instance there is no "Aux 10" available in the Aux outputs list...

It works like this:  If E-throttle is not enabled, Aux 4 works as normal.  Aux 9 in the software will drive the hardware pin labelled "Aux 10".  Aux 9 hardware pin cant be used.

If E-throttle is enabled, Aux 4 in the software controls the hardware pin Aux 10.  Aux 9 in the software controls Hardware pin Aux 10.  Aux 4 pin cant be used.

So I know that sounds crazy confusing but I think the fix for you is simple;  Leave Aux 9 in the software set to fuel pump or whatever function you want to use.  But connect the fuel pump relay to the Expansion pin labelled Aux 10.

 

Having said that, I dont think the way you had set it up should have caused the "E-throttle IC over temp" error so there may be something else wrong.  Please swap the FP relay to Aux 10 pin and report back.

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So I couldn’t go to sleep before checking this out haha. Adam indeed it works but when I key off it turns on again like the ecu is sending again a ground signal even with the ignition off. Once I key on it stops. If I do a test on it will turn on like it’s suppose to. Maybe because I have pin 30 and 86 jumped together on the relay and since they are 12v directly from the battery once the ecu shuts down it grounds automatically to car? I’m gonna try like a 12v signal from ignition on only and see if that works 

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20 hours ago, Luis Lopez said:

Maybe because I have pin 30 and 86 jumped together on the relay and since they are 12v directly from the battery once the ecu shuts down it grounds automatically to car

Yes this is your problem.  The 12V side of the relay coil must be ignition switched.  If it stays live with ignition off, the flyback diode in the ECU will keep fuel pump running and will also prevent the ECU shutting down.

Correct wiring from the help file:

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