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voltage vs tach

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=118426
Printed Date: May 11, 2024 at 2:30 PM


Topic: voltage vs tach

Posted By: dvaldez0989
Subject: voltage vs tach
Date Posted: December 11, 2009 at 9:46 AM

so i have been reading here and noticed most people use tach.Now i will use tach if it is easy to get to but most of the time i use voltage. my question is why tach over voltage??



Replies:

Posted By: ajstetler
Date Posted: December 11, 2009 at 10:11 AM
Voltage sense has a predetermined crank time, which is usually programmable. The R/S monitors the voltage difference after the vehicle is started. That means on older vehicles or those that have weak batteries, it may take longer to crank and result in an unsuccessful remote start attempt. Obviously you don't want to over-crank resulting in starter grind.



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Big Al




Posted By: dvaldez0989
Date Posted: December 11, 2009 at 10:51 AM
well besides the fact that it is an older car it won t hurt anything as long it is the crank timr is correct




Posted By: KPierson
Date Posted: December 11, 2009 at 1:02 PM

I installed a remote start on my wifes car a few years back outside in the cold for Christmas.  It was the only car I ever did that I didn't hook tach up on.  When it got cold the car wouldn't start (the crank time wasn't long enough).  It would crank, not start, wait about 20 seconds while it checked the voltage, then crank again. 

The remote start can use the tach signal to precisely control crank duration instead of just using a preset value.  Therefore, with tach, the remote start has the ability to work for the life of the car as opposed to a voltage based car that as it gets older might not start up.

Also, the tach is used to shut the vehicle down if the motor is overrevved.  This can be useful of someone is climbing in to the vehicle and they accidently step on the accelerator.

It's only one extra wire and as long as you know a bit about motor layout (ie where the fuel injectors are) it typically isn't hard to hook up.  There are numerous benefits and virtually no drawbacks.



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Kevin Pierson




Posted By: tommy...
Date Posted: December 11, 2009 at 8:48 PM
Also improves customer comebacks or calls for what KP mentioned...I take pride in having as few "comebacks" as possible...I.E....Tach,factory dis-arm...! I almost always use the fuel injector wire...Usually easy to find and differentiate...Over-all it makes you a better installer by improving the customers outlook on situation...Remember for every bad experience a customer tells 10 people...but only 1 person for every good experience...! You can also use it as an upsell...!

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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: dvaldez0989
Date Posted: December 12, 2009 at 9:07 AM
wouldnt you say it is easier to do voltage on a diesel?? im not arguing the point that it is better to use tach but since the viper 5901 came out i have used voltage most of the time, and i havent had any comebacks




Posted By: tommy...
Date Posted: December 12, 2009 at 10:12 AM
Ummm...you do more diesels then gas...? I dont install the 5901 so if the voltage works...great...But overall...with all my experience...Tach is the way to go...!

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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!





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