M150 Engine reference signal

[Islandworks]

A bit of a simple question that I cannot find a straight answer for. I have a Porsche 964 that uses a VR sensor and missing tooth flywheel together with a separate hall sensor.

In my previous ECU setup I pulled a ref+ and ref- signal straight to the ECU together with a shielded cable.

In the M150 documentation and M1 tune it seems to me like I only need one signal to the UDIG1 and then pull the hall sensor to UDIG2.

Where does the second wire from the VR sensor go or alternatively what have I missed? It feels odd to simply ground the second wire and then on top of that also shield it.

Would be great with some help on this!

[NathanB]

The second wire from the VR sensor will go to 0V A

[Islandworks]

So the sensor 0v for A?

Is that somewhere in the documentation?

[NathanB]

Technically any of the 0V pins are suitable. However, our recommended wiring convention is as follows:

Sensor 5VA and Sensor 0VA:
This supply should be used for all switching, frequency, or rotation sensors (such as Engine Speed, Camshaft Position, Driver Switches, Fuel Flow, etc.) Wire gauges should be the maximum allowable for the pin size in Autosport ECUs (M190, M170, M182), AWG22. For Tyco ECUs (M130, M150, M142), AWG20 is preferred, AWG22 is acceptable.

Sensor 5VB and Sensor 0VB:
This supply should be used for all analogue voltage and temperature sensors which are engine-critical (for example Throttle Position, Manifold Pressure, Throttle Pedal A, Coolant Temperature). Wire gauges as for Sensor 5VA.

Sensor 5VC and Sensor 0VC:
This supply should be used for supplementary engine-critical sensors (example Throttle Pedal B) and all non-critical sensors and devices (example GPS supply, Suspension position). Wire gauges as for Sensor 5VA.

[Islandworks]

That's a very good answer, thanks!

Now the issue I have is that I've pulled the 0V A (harness wise) to be used for fuel pressure, manifold, oil pressure and I'm already fully utilized on the bulkhead connector...

I'll have to work a bit more to pull both the A and the B line up there...

[David Ferguson]

Why don't you splice it on the engine side of the bulkhead connector? I usually only have one "0VA" pin on a bulkhead connector.

[Islandworks]

If it's acceptable to use the same 0V "A" for fuel pressure, oil pressure, MAP, throttle pots and one digital switch it would be the best.

Looking at the above recommendation I was thinking there could be a risk for noise?

[David Ferguson]

It will be OK.