Quick question on Cobb Ethanol sensor

[SimonSTI]

I have a Cobb Ethanol sensor, which seems to be the same brand (GM?) as the Link one.

Cobb use little electronic to convert to a 5V signal and is using the TGV input signal to send the info to the ECU. Could i use the digital signal directly from the sensor in the TGV input instead and get the fuel temperature as well by doing so?

tx,

[Adamw]

The TGV inputs are connected at the ecu end to analog inputs (0-5V) rather than a digital input that is needed for the ethanol% & temp.

So you could possibly use the TGV wire but it will need to be moved at the ecu end to a DI.  There arent too many spare DI's on the WRX104 ecu, does your car have cruise control?

[SimonSTI]

I though I could map an analog inputs to a DI GP input?

Yes I have cruise control. So looking at the diagram looks like I could use DI10 which seems unused, but it is labeled as "main switch" on the OEM ECU?

Is the neutral switch used anywhere in the ECU logic? It's not configured and doesn't seem to have any side effect at the moment, could be another option.

 

[Vaughan]

6 hours ago, SimonSTI said:

I though I could map an analog inputs to a DI GP input?

you can use an analog as a switched DI input but the analog inputs don't have the hardware to read frequencies and Duty Cycles (The ethanol and temp data are transmitted as a pwm signal).

Neutral switch can be used for idle trims but I wouldn't consider it to be super necessary so it would be a good option.

[Adamw]

DI10 is the main enable switch for cruise control.  The neutral switch is a good option as suggested.