Tach signal tap

[Adamn]

I'm trying to hook up a window switch on my car and I don't know what wire on the coils to tap for the tach signal. Any help is much appreciated

 

[03cobra#694]

Most use coil #1 which is pin #26, it's a light green/white wire. I taped in down by the ECU in the passenger kick panel.

 

[Adamn]

Most use coil #1 which is pin #26, it's a light green/white wire. I taped in down by the ECU in the passenger kick panel.]


Thanks a lot. Do u know if there is a spot inside the car to tie into the TPS instead of doing it right off the throttle body?

 

[03cobra#694]

Yeah, you can tap in at same spot as mentioned above. It's pin #89 gy/wh wire.

 

[Adamn]

Yeah, you can tap in at same spot as mentioned above. It's pin #89 gy/wh wire.

Thanks a lot

 

[IUP99snake]

You'll need a tach adapter unless your device has a programmable tach input. If that is the case, set it to .5 pulses per revolution-- On a 4 stroke engine, the injectors and coils fire once for every two revolutions.

I recommend tapping into an injector instead of a coil. Here's why: The factory ignition will produce multiple sparks per firing stroke under 3000 RPM. This creates a tach reading 2 or 3 times higher than it should be. You could be at 2500 RPM but the device will read 5000 RPM's instead. That could cause problems if your window switch is set below 5000 RPM.

Unlike the coils, the injectors will always produce a tach signal of .5 pulses per revolution. You can tap into the positive lead of any injector.

This trick works great on my AEM Wideband Failsafe gauge.

 

[MrCaliKrome]

Great info! Do you have a write up on the AEM Failsafe install?

I have the gauge installed with boost and A/Fvreading but dont have the failsafe set up yet.