FAST and After Market Tach..How to Hook Up?

[Hot Air]

I have a VDO tach and FAST. What wire do I send to the tach?
Conrad

 

[HighPSI]

It doesn't matter wether you are using a FAST or stock ecm. The tach output is on the ignition module. If you are using a stock harness, you can get the signal from the unused plug (with two white wires) behind the alternator. If you are using a stand alone harness, you will use the unused white wire coming out of the module