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Motec M150 wiring

EFI Wiring Fundamentals

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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I was originally building a harness for a friend under AEM infinity EMS but decided to jump on the Motec wagon. Went with 2 pdm15 and a m150 grpr (I think that's right). Problem is I am not familiar with how Motec ecu and pinout work. Not sure what half bridges do and what not. I have a spreadsheet I would like to share with someone if they could help me out.

Evo 9

2.0 mivec

Bosch dbw throttle body

Penny and Giles rotary potentiometer for gas pedal

Drenth transmission with mme motorsports paddle shift system

M&W cdi box sequential spark

Lambda to CAN wideband

All I can think of right now. I have assigned all inputs on spreadsheet. Just want to see if I'm understanding it correctly. Thanks in advance

G'day John. I'm away at the moment, so if you havent been able to get the help you're after before I get back next week I'll have a look at your spreadsheet and give you a hand. Cheers.

Cheers. Thank you

Hi John,

I have a little idea about wiring MoTeC products... Post the spread sheet up and I'll have a look at it for you.

The Half bridges are a high amp switchable output, that can either supply voltage (high side, 9A) or provide a ground (low side, 12A) to the device under control. They can be either switched or PWM in their controlled output. If you combine two of the together (i.e. HB1 and HB2) then you get a full bridge, this allows for a motor, such as a DBW, to be driven in both directions.

G'day John. Back on board, post up that spreadsheet and we'll have a look :-).

Hope you can understand it...Anything power related is going to PDM and sensor will be to m150. Letter is plug number is plug number. I've put questions marks to the ones I have no Idea where they go and the rest is roughly from what I gathered from what I have read. Thank you much for your assistance

Attached Files
  • kevin-evo-9-wire-harness-diagram-071118.xlsx
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

Hi John,

There is not a file attached.

Sorry, it should be there now

Hi John,

The main points that have come up with this chart are;

The Cam and Crank sensors should be powered by the 5V supply from the M1, not Battery+.

The injectors should be feed from the Battery+ supply, not from the Half Bridges. The Injector Lowside connections are correct.

You do not need a 5V feed for the Oil Temp Sensor if it is going into an AT.

The AT inputs are internally linked to the 5v+ rails, so AT1 and AT2 use 5VA, AT3 and AT4 use 5VB and AT5 and AT6 use 5VC. These must be linked to the matching 0V supplies for proper ratiometric operation.

TPS signals go into AV inputs, not UDig inputs. The UDig Hybrid inputs are available as a resource for some specific throttle systems that use a Sent signal.

Udig1 cannot be used for a Wheel Speed input as it is configured in the Firmware to be the Engine Speed input only.

With the M150, you need to have Battery+ fed to C26, B13 and B19. Battery- is to C10, C11, A24, A25 and A32.

I would use different colours for the CAN High and CAN Low wires, as it makes identifying them after they are twisted much easier.

appreciate the response. So how doe the 3 wire temp sensors get wired. I have 5V, 0V, and singal on the aem sensors we have. So for UDIG1, i would need to land the Tacho signal from CDI to this pin? Thanks for the reminder about the perm power and chassis grounds. I had another tab for the sensors inside the car. Primarily for the paddle shift signal, tank pressure. Where do these land on the M150. We are also looking to do a rotary trim pot switch for adjusting boost levels as well as a push to pass button the the steering. Not sure where these land either. Thanks for the help. More familiar with the AEM EMS. New to Motec

UDIG1 can only be connected to your Crank Position Sensor (sometimes called the Reference sensor in many MoTeC documents). You will need some details about your 3-wire temperature sensors (you may be able to connect just two of the wires to a temperature input - 0V and Signal), or you may use all three wires and use one of the Analog Voltage inputs. Generally you want to use Digital or Universal Digital inputs for your switches like shift paddles and push-to-pass. Connect one side of the switch to the M150 input and the other side to 0V or ground. Your rotary trim pots would use the Analog Voltage inputs, as they provide a variable voltage output depending upon position.

This is exactly what Stephen said above.

Hi John,

Having a look here at the wiring information for the AEM Temp sensors, the 5v+ feed shown in the diagram is internal to the ECU and is linked to the input used for the temp sensor by a 1K ohm internal pull-up resistor, the same as the M1 and any other ECU that uses AT inputs.

I would use the Digital inputs for on/off (paddles and PtoP) switches before the Udig or Analogue inputs and I would connect them to the 0v only, not to ground. Any switch inputs that have a varying input voltage I run onto the AV or AT inputs.

Hi Stephen, I assume this is for constant power not switched power correct for those pins you mentioned. B13,B19,C26

Hi John,

You should have switched Battery+ to those pins, either through an ignition switch or master switch.

David Ferguson - you've stated that the UDIG1 (PIN D1) can only be referenced to a Crank Speed Sensor (Motec references it as the Engine Speed Sensor). I have gone through all of their documentation (of at-least what is available online) and cannot for the life of me find where Motec have stated that this sensor is locked to ONLY be used for the engine speed sensor.

From my understanding all UDIG* ports can be used for any hall effect, reluctor or vr sensor - eg.

* Cam angle sensors

* Crank speed sensor

* Gearbox speed sensor

* ABS/Trac speed sensors

Please correct me if I am wrong as I am relatively new to wiring world of Motec, I am very confused after reading your statement (no offence).

Have you installed M1 Tune and tried to configure a package? You will find that with the current firmware packages, UDig1 is always allocated to the Engine Speed Reference / Engine Speed Pin / Engine Speed Voltage. This can be verified with the M1 Tune menu Help->Firmware Wiring...

So, it's locked in the firmware -- in fact if you use M1 Build to make your own firmware, you will find that Engine Speed Reference is an IO Resource Constant, and the only constant available is "Universal Digital Input 1".

BTW - Stephen Dean (who works for MoTeC) also stated: "Udig1 cannot be used for a Wheel Speed input as it is configured in the Firmware to be the Engine Speed input only."

So this is a fact, despite no documentation that explicitly states this.

I saw in the post above that Battery Positive should = a switched (e.g. ignition switched power supply).

Is there also a permanent fused power input, say to D12 Battery Backup?

Hi Aaron,

The memory in the M1 is non volatile so it doesn't need to have a battery backup supply. The Battery Backup pin that is mentioned in some documentation is there for use in OEM systems that need to sense a load on that pin in a standard loom, in a non OEM system it isn't needed.

Thanks Stephan... more learning switching from an AEM Infinity. I don’t regret getting the Infinity and “cutting my teeth on it”, but I always wanted a MoTeC and am excited to start this journey.


I have been searching prior posts and found this one very useful. New to MoTec and am building the harness for an LS based powerplant with an M150. From one of the posts above which stated, "With the M150, you need to have Battery+ fed to C26, B13 and B19. Battery- is to C10, C11, A24, A25 and A32", can you feed the +12V supply from the PDM (PDM 30) or does this need to be a fused link directly from the battery? Also, for the ground connection, do these need to come directly from the battery?



PDM supply of ECU power is typical. The PDM is the fuse.

I would use a good chassis common ground, that the battery is connected to.

Thank you David. Perfect!

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