Sleeper Needs Boost!
sorry TEL but this is a much better explination. though with yours i still got it. thanks.SquishyPanda said:the Sentra's tach is designed for a 4-cylinder signal. VQ has 6 cylinders. That's why a lot of aftermarket tachs have a switch on the back for 4, 6, or 8 cylinders. The sentra tach is reading 1.5x faster than the VQ is actually revving.
On a distributored ignition system, the coil fires 2 times per revolution on a 4-cylinder engine, but 3 times on a 6-cylinder car. If the tach is counting sparks, and dividing by 2, it's not gonna match up.
Those cars have distributorless coil pack setups, but the tach still works pretty much the same way. I did that by accident on my old truck... It was a V6 and I left the tach set to 8-cylinder. Confused the hell out of me.