Print Page | Close Window

help with tach issue

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=44346
Printed Date: July 07, 2025 at 5:21 AM


Topic: help with tach issue

Posted By: taz23340
Subject: help with tach issue
Date Posted: December 03, 2004 at 10:47 AM

hi guys,

fist post here so hope i make sense in what i am asking.

i have installed many starters in my time but it's been a while now as i have been out of the business for 4 years so just wanted to refresh my memory on the tach wire.

in the past i used to have a tach sensing box, but i dont work at the shop that has it and only have my dmm, if i remember correctly we need approv 5v at idle to be able to get the car to start and run, also i see in the magazines more and more units have a tach sensor built that emulates teh tach

any help would be great thanks




Replies:

Posted By: hagmanti
Date Posted: December 06, 2004 at 8:43 PM
It'd help if you mentioned the car you were installing in. :)

Regardless, you're looking for a wire that measures somewhere between .8ish VAC and 5ish VAC at idle and that, more importantly, varies in strength w/ engine speed. Try measuring across both neutral and 12V. (I know, it shouldn't matter, but I've often found it does.)

Frankly, you're better off checking a few wiring diagrams (and then verifying) than you are just randomly poking wires. I've found (i.e., been pointed to) tach in some awfully weird places. And I've had RS units learn tach correctly from signals that did not look like a tach signal on my DMM....

Me





Print Page | Close Window