Quote: Originally Posted by
Twidget 
The EMS knows the engine speed at all times since it gets the info off of the cam and crank sensors. It just doesn't have an output for hooking up an external tach. I'm sure the hardware itself supports it, since AEM uses different I/O daughterboards with the same actual brain setup. AEM just must not have seen the need to include a tach output since we're still using the factory PCM to drive the stock gauges.
Chris
You can pull engine speed off serially. But yah, there is no standard tach output. A tach adapter works well and is cheap and relies on the coil firing or something. That is if you don't want to go the serial way.
D
