What kind of signal do the factory tach and Speedometer gauges receive from the ecu? I’ve always really liked the way the factory integra gauges looked and am hoping to retain them while swapping to a Holley stand alone. TIA

 

factory tach is 0-5v PWM signal
factory speedo is 0-12v PWM signal
(they do not come from the ECU)

 

thank you good sir. Does the speed come straight from the speed sensor? That tach signal I’m pretty sure can come from my holley but if I can get around having to use I/o for the Speedo that would be cool

 

Yes, speedo signal is straight from the vehicle speed sensor (VSS) orange wire.

 

Tachometer can also run off of the ICM signal. The tach output from the distributor is this, as is the NEP output on obd2b ecus.

the VSS pulse comes from the sensor and is “tee’d” at the brown distribution connector near the ecu under the dash.

 

Thanks guys, I think I can work with this

 

is the tach a pwm- or a pwm+ that it requires? The Holley outputs a pwm-