PontiacBonnevilleClub.com

Posted: **Mon Aug 30, 2010 6:47 pm**

Hello Guys. I am having a very difficult finding the tachometer wire for Northstar engine for wiring up a security auto start. I really need some help because this is mainly my only hang up. . I begging for help here. Take Care.

Posted: **Sun Sep 12, 2010 9:59 pm**

www.commandocaralarms.com

try that website and see if you can find the wiring diagram you need, they offer free wiring diagrams for remote start units

Posted: **Mon Sep 13, 2010 12:18 am**

I am not familiar with the northstar and GXP, but I do have the tachometer circuit description from the 2k FSM and I am willing to bet the others are done very similar.

The tachometer displays engine RPM (speed) anytime the power mode is RUN. The engine RPM is calculated by a discrete signal sent to the IPC from the PCM. The engine speed signal is active low, with a pull-up resistor located in the IPC and connected to switched battery voltage. The signal is a square wave with a 25 to 75 percent duty cycle. Each engine revolution is represented by 2 input pulses. Engine speed is calculated using the time difference between the 2 consecutive pulses. Accuracy of the final calculations are +/- 25 RPM.

Basically there is no single wire. It is calculated internally in the instrument cluster based upon the signals from the PCM. The PCM gets it's information from the CPS and cam sensor.

What is the need for the tach input?

PontiacBonnevilleClub.com

Auto Start Tachometer wire North Start

Auto Start Tachometer wire North Start

Re: Auto Start Tachometer wire North Start

Re: Auto Start Tachometer wire North Start