Motec M142 wiring.

Hey guys, this is my first Motec ecu, coming from Haltech.

Basically, I am running a Motec M142 and a Motec PDM 30 in my racecar after removing my Nexus R5.

I have completely wired up all the modules, compnents and sensors fairly easily but could for the life of me not find "ignition" wires anywhere on the pinout/wiring diagram. I spoke to my dealer and he said I should wire the 3 Bat+ to the PDM directly and run the ECU off the PDM. Basically what I'm trying to wrap my head around is, how does one go about wiring an on/off switch into the ecu?

Any help would be greatly appreciated, sorry if this is the wrong section to ask this, I did try the search function and it seems like I'm the only person who cant figure this. TIA.

You use a UDig input for the ignition switch (unless you wish to send it over CAN from the PDM). Then configure the Driver Switch xxx Resource to use the selected UDig. Then set the Engine Run Switch Index to the driver switch you configured. Now, this switch will control if the engine runs or stops. This will allow you to crank / monitor the engine (oil pressure, RPM, etc) with the ignition off, so the fuel pump, injectors, and coils aren't triggered.

So, if I connect UDig to 12v, the system should turn on, should I put a fuse inline or will it be fine without it? Will the ECU wake-up the PDM via CAN?

No. Since you indicate this is a race car -- the PDM would be powered with the master switch. The ECU would either be ON whenever the PDM is, or you may have a cockpit main power switch that enables the ECU, Dash, etc.

The ignition switch would just be used to enable/disable the ignition (ie, allow the engine to run or cause it to stop). If the switch goes high (ie, 12V when on), then I would wire it to the UDig, and program the active edge to "Rising Edge" and the Threshold to something like 7 volts.

The ECU is "on" whenever the Battery and Ground connections have power. That is why the PDM or master switch could power it.

I typically use a PDM or a circuit breaker for the ECU power.