Aux Table not releasing a ground

[USAdude]

I am building a patch harness for a 2003 Lancer Evolution for use with M400. I am trying to use Aux 6 as an Aux Table to switch to ground any time the ecu is powered (I have the ecu only powered with the ignition in the "ON" position. I'm using this ground to activate the main relay which has constant battery voltage being fed to it at all times. The problem is that once the ignition switch is turned back off, it appears that the ground doesn't release completely so the accessories powered by the main relay simply flicker with very low voltage. My settings are below.

Aux 6- Aux Table

Parameters:
PWM/Switched 1
Output mode 0
Polarity 0
Frequency 10
Min Duty 0
Max Duty 0
Hyst 0

Table (no axis selected)- 100

I realize that I could change the battery voltage being fed to the main relay to be +12v only with the ignition switch on but I would like to complete this without changing any factory wiring.

[SprinterTRD]

You cannot have constant power to relays connected to the ECU. It feeds back through the drivers and keeps it powered. The M800 drawing shows all relays must have +12V removed when the ECU is turned off.

[USAdude]

I see that in the drawing, I didn't realize that it couldn't do what I need it to. The factory ecu and other plug-and-play options don't have a problem dealing with constant +12v being fed to relays. What is different about the Motec ECU? It's going to be a large task, to remove battery power from all of the factory relays.... seems to me that there should be another way.

I have another question that I am unclear about.... Can someone explain the difference between Output Lo when Active/ Output Hi when active? I am attempting to ground the factory relay to run the thermo fan but it will not work with the Polarity set to 1, regardless of the on/off temp. And with polarity set to 0 it is on ALL THE TIME regardless of on/off temp.

[Blu302]

With the Aux outputs etc on the ECU, they are internally grounded when the ECU is shut down. I had the same problem and the way around it is to have the relay grounded with the ECU supplying power to the relay when you want it on(output hi when on). the output hi/lo is which way you want the output to go (hi=+12v, lo=0v) when the output is turned "ON". hope that helps

[MarkMc]

Hi USADude,
It's true you casnnot have 12v feeding into an Auxiliary output becasue it will falsely keep the ECU alive. Having said that our plug and play ECUs for the EVOs are designed to take all of the factory powering into account. Can you send a diagram of how your patch loom is wired (need pin numbers) and I can have a look and get you to change it to make it more like our plug and play. There have been many EVOs wired with patch harnesses before.

Email your diagran to mark.mccoy@motec.com.au.

[USAdude]

MarkMc: Email sent. Thank you

[Scott@FP]

If you have an adapter harness in between the OEM vehicle harness and the ECU, use an NPN transistor or small micro relay to actuate the OEM MFI relay. Use the Ign1 (B+ in key position Run and Start) on OEM harness ECU pin 82 (black/red stripe) to the P or coil of relay, ground other side of relay coil, put contact side of relay on OEM ECU pin 36 (red), ground the output side. Now use OEM ECU pin 12 or 25 (OEM MFI relay to ECU power) into the M800 pin A26.

Everything will work as it should and you save an M800 output, all the voltage based comps will work correctly if you are using the OEM wiring for injectors and ign coil B+.

What I usually do is use OEM ECU pin 12 to power the ECU, then pin 25 for Lambda heater and other accessories that need to be powered parallel to the ECU.

[Scott@FP]

BTW the fan control for the OEM main (driver's side) fan is not an on/off relay control, it is a PWM signal. If you set your temp on/temp off for a bit larger spread than a normal fan it will operate same as the factory fan and vary the fan speed proportional to temp.

Freq = 4000 Hz
Polarity = 1
output mode = 0
min duty = 0