measuring tach signal

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=1067
Printed Date: July 04, 2025 at 6:42 AM

Topic: measuring tach signal

Posted By: timetoride
Subject: measuring tach signal
Date Posted: May 31, 2002 at 6:58 PM

How do you measure the tach signal with a multimeter. I gotten a wire that has a 12v when the vehicle ignition is on and then a 6v that bounces when the car is running. But on the ac side all i get is constant 13.2 volts.

I'm trying to figure is the ground of the multimeter goes to the ground on battery and positive to tach wire. Do i use the meter in DC or AC to determine if that's the correct tach wire. What reading should i see once i do connect to this wire.????

Replies:

Posted By: Velocity Motors
Date Posted: May 31, 2002 at 7:08 PM

With voltmeter set to AC, its positive lead applied to 12V+ and the negative lead attached to the target wire, the meter should indicate one volt or more (AC). With the vehicle running, the voltage should rise as the accelerator is pressed. What vehicle are you trying to find a tach signal for ??

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Posted By: timetoride
Date Posted: June 04, 2002 at 9:33 PM

I'm was searching for the tach on a ford expedition. 5.4l triton v8 WHITE/ pink cable

Posted By: Velocity Motors
Date Posted: June 04, 2002 at 11:20 PM

I ended up using the injector wire off # 1 on top of the engine, passenger side. There are two sets of wires on each injector, use the non common one and set the remote starter to 2 cylinder or if you have an automatic tach sense, just go through the tach learn and it will work better than the tach wire.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

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