20V TPS & 4AGZE CAS -> MoTeC (check the working of Rex...)

[Rex_Kelway]

Hello All,

Rex is wiring His stupid AE86 up and seeks the assistance with two sensors.

ECU is Motec M4

He has spent the last couple of mins looking at the 20V wiring diagrams. But as He is no expert, before he finalises anything it be wise to gain consensus from those in the know.

This is what Rex has put together in his head.

20V TPS:

Yellow (pin 1) - 5V (ie power from ECU)
Rex (pin 2) - Position Signal (to ECU)
Blue (pin 3) - Not used, presumably full throttle switch for factory ECU
Brown (pin 4) - 0V (earth back to ECU)

Hopefully He has it correct...


The other is the REF and SYNC signals. Motec uses two seperate mini looms in case the two signals come from different areas and different sensor types.

So basically you have power, ground, signal and sheild for each of the REF and SYNC signals.

Now, using the Motec diagrams, it appears the sensor is un-powered, IE there are only the REF and SYNC signals and 0V. This kind of makes sense being a magnetic pick-up, as Rex understands it.

So does one simply leave the Motec's power leads unconnected?

Do both of the REF and SYNC 0V wires get joined at the sensor along with their sheild wires?

If you get what He means.

Thanks lads, if you can confirm or have experience Rex would appreciate your helpness.

Cheers,

[Hen]

It sounds like you have the right idea. My experience is with Wolf, not Motec, but I hope they are similar.

Leaving the power supply wire disconnected (but insulated) is fine

The shields should each be connected to a pin at the ECU end. If so leave them unconnected at the sensor end.

Connecting the sync and ref 0V wires *should* be ok, but a nicer way of doing it would be to have each 0V wire run direct to the relevant pickup in the CAS (if you got anal you could even run each wire to the standard 4pin CAS plug since you are only using 2 pickups, the 4 pins would then be: sync sig, sync 0V, ref sig, ref 0V)

Hen

[takai]

Yup, both Rex and Hen have it right IIRC, the Haltech is similar again.

P.s. wow, Rex is actually wiring up his AE86.

[RobertoX]

The way we had the M4 on our FSAE car wired was as you describe, the 0V connected to the sensor's sheild and the signal to the signal wire on the sensor and the power left off.

It worked fine but took a while to get set up depending on the position of the sync signal wrt the ref. And then there was the strength of the signal (dammit I hate "sync not ok" lol)

[thechuckster]

most toyota sensors are VR (variable reluctor) and each sensor has a signal and earth connections. In the dizzi-based CASes, the earth si common for all two or three sensors.

They're not powered as the VR sensor generates a current when the ferrous trigger wheel passes the sensor.

The earth wire has to be grounded at just one point so if you dont connect it at the ECU, make sure it connects to the engine/chassis earth at the actual sensor.

My VR sensor's earth is the shield for the VR signal wire and i bring it back to the ECU and ground it there with all the other sensor earths (TPS, O2, CLT, MAT).


edit: i have a rock-solid RPM signal, despite that lead travelling many feet back to the ecu.