# Tachometer signal...



## bblocher (Jul 30, 2008)

Hey man. I've been there.

You need neither. Technically the crankshaft sensor was feed into the ECU which the ECU uses to generate a new signal to the tach. In my case they were different. The crank signal was 5v and the tach signal from the ECU was 12v. My tach requires two 12v pulses. I have all the details on the blog.

I'd recommend getting the service manual, if you don't have it already, and find the trouble shooting section for your tach. You should find hints in there as to what you're looking for. It will have you check certain connection pins to ground, etc and the one going to the tach should say something like 12v pulses when checking it.

You could also reconnect the ECU to the crankshaft sensor and crank the engine watching the output of the ECU for the tach signal.


----------



## piotrsko (Dec 9, 2007)

I'd use the crankshaft sensor since it usually has a nice mounting pad.

gap should be about .006 to .008 and I believe that the sensor will need a voltage source. As how to hook it up, I'm no good there without pouring for hours over the schematics for the tach. since my sensor is 2 wire I suggest a common ground, power in on one lead (need schematic for this) signal off the other wire in the sensor going to the tach. I'm guessing that the count wont be correct, but get it working first.

if the tach REQUIRES a 12 V signal there will be other considerations like perhaps needing a different hall effect sensor because the crank sensor ought to be 5 v


----------

