My LS3 E38 ECM has a tach output on pin 48. I understand the output pulses are same as a 4 cylinder, in other words two revolution per pulse. Now comes my 2003 Boxster OEM tachometer that until now has been working with the Porsche 6-cylinder whatever pulses. Not to worry, I am out ahead of the problem. I bought a tach adapt from Pelican Parts. The riddle is: Do I set the dip switches for an 8-cylinder engine and a 6-cylinder tach? or.... for a 4-cylinder engine and a 6-cylinder tach? When I am a little further along and the engine is runnning I can come up with the answer by trying both ways. Meanwhile .........
