MoTeC Global Forum

Hi guys,

I'm rewiring the car and removing factory ecu and was wondering what the attesa ecu is expecting to see as inputs to keep functioning as normal?

I've read a few conflicting stories and was hoping for a definite answer if anyone can help.

Cheers

Hi Shane,

It's expecting to see a buffered throttle position signal from the ECU. This can't be just spliced to the TPS though, it need to drive some current to the ATTESA unit.

Try the attached circuit to generate the ATTESA output from an M800 ECU.

Setup the m800 output as function 3 – Aux Table.
Parameters –
Frequency = 10000Hz
Polarity = 1
Output Mode = 0

Set the table axis to Throttle Position.

When all connected, test with a multi meter. You should see voltages like this.
0% in the table should be ~0.0V
50% may be ~2V
100% may be ~4.5V

Tweak the table for the desired output. Ideally the voltage will be similar to the throttle position. It's best to measure the signal out of the OE ECU in reference to the TP voltage when connected to the ATTESA, then connect the circuit and set the M800 up to output the same. Eg, TP = 1v, OE out = 0.9v. Tp = 3v, OE out = 2.7v. Tp = 4.5v, OE out = 4v. Etc. Then when the M800 is connected move the throttle to output 1v and set the duty cycle so the output reads 0.9v and do the same for all points.

Darren.

hi i am trying to do the same thing on r34 but can you
explain attached circuit its using two resistor 270/1k
and one capacitor that all we need

How about the RPM signal? Is that required by the ATESSA ecu? Is TPS the only signal that needs to be provided to the ATESSA from Motec to make the 4WD system functional?