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Impreza v3-4 Wheel speed


Babych44

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Car is 1998 Impreza GT, tell stupid what I have to put to settings that shows me wheel speed? Or is it even possibly with this car? Would need it for closed loop idle, and also for gear showing. Sorry my bad english, try to understand :(

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You probbaly dont have ABS sensors on that car to tap into so you wont get individual wheel speeds. Your speedo will be driven by a gearbox sensor.

connect the vehicle speed sensor in the gearbox up to any digital input, and configure this as LR wheel speed. Leave the wire connected to the speedo as well, dont just cut it.

then under chassis & body, set driven wheel speed source to this DI. Also set non-drive wheel source to the same DI.

 

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Yes, plug-in ECU. WRX-STI, ver 3-4 ecu. Speedo works fine, D1 set to LF Wheel speed, pullup resistor=off, on Speed sources both driven and non driven is LF Wheel speed. Should I wire extra wire from gearbox speed sensor to ecu like "cj" suggested? :o

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  • 5 weeks later...
  • 8 months later...

Hi! I Have similar question. V2 car with speedo cable, all wired to run on v4 ECU. V4 plugin now. Speed is 0 without pull-up, but with pull-up switched on once car is moving readings are inconsistent and jumping +/- 50 km/h.

With previous ECU (OEM v4 with daughterboard) speed readings were correct.

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There is no other setting in the ECU that can affect it.  You might have to get an oscilloscope on to the speed wire to see what is wrong with the signal.  Im not sure about subaru's, but in Nissans and toyotas from around that same era it is common for the reed switch that generates the signal in the back of the speedo to get sticky/erratic.

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Yes, I understand. Funny enough, VSS wire from speedometer to ECU is also connected to external datalogger and central diff standalone controller, and while diff controller seems to see speed just fine, both ECU and datalogger show noisy signal which does correlate to speed... Attached are screenshots from PC log and from datalogger (together with GPS speed channel).

I have v4 speed sensor for gearbox to try wire it directly to ECU, but this means ditching speedo cable and no readings on dash/odometer...

Screenshot 2020-03-16 11.45.08.png

Screenshot_20200316-114234.jpg

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