How much max volts on tach?

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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=45243
Printed Date: May 11, 2024 at 11:41 AM

Topic: How much max volts on tach?

Posted By: ivanca
Subject: How much max volts on tach?
Date Posted: December 14, 2004 at 11:59 PM

Anybody knows that?Thanks

Replies:

Posted By: wblakes
Date Posted: December 15, 2004 at 12:01 AM

the highest i seen so far is a little over 7 volts on toyotas. on other cars i usually get around 5 or 6.

Posted By: ivanca
Date Posted: December 15, 2004 at 12:08 AM

is it higher if engine runs fast? such as when u drive car on high way. is the tach volts goes up with the speed?

wblakes wrote:

the highest i seen so far is a little over 7 volts on toyotas. on other cars i usually get around 5 or 6.

Posted By: wblakes
Date Posted: December 15, 2004 at 12:10 AM

sorry can't answer you that cause i always measure it when it's not driving. but if you wanna know i guess you can measure it and have some step on the gas pedal to see if it goes higher or not. i think that's the same thing as driving it won't you?

Posted By: cgalvin29
Date Posted: December 15, 2004 at 12:22 AM

Yes and no, on dc it may vary a little but on AC which is what is should be on it will rise with the rpms of the vehicle, you can also test on frequency (HZ) depending on if your meter has that and it will give you a much better idea of if your on the right tach or not.

Posted By: customcaraudio
Date Posted: December 15, 2004 at 6:53 AM

As above mentioned yes the ac voltage is correct and 99%of the time it should sit between 1 and 6 VAC. depending on the revs

Posted By: jaxman
Date Posted: December 15, 2004 at 7:48 AM

What do you need the tach for ?
Normally the tach will go up with your RPM and not with the speed fo the car.
Speedpulse will go up with the speed of the car.
Tach will meassure in AC and not DC and if you can't find it in the car use the injector wire.

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Posted By: markcars
Date Posted: December 15, 2004 at 7:58 AM

ivanca, I am not sure if you need this info for your remote start, but if the answer is yes, then you will need that tach voltage only during a "remote start". After that, the voltage is not even required for the remote-start unit. Hope this is relevant to you. And maybe to answer part of your question, on one of my cars (a toyota highlander) it went up to 6 volts when I tested it by revving up the engine.

Posted By: jaxman
Date Posted: December 15, 2004 at 8:05 AM

markcars ... this is not quite true :"then you will need that tach voltage only during a "remote start"

If the system is smart enough will monitor the tach signal and if the tach goes much over initial limit the engine will shut down of course also if the key is not in the ignition :)

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Posted By: markcars
Date Posted: December 15, 2004 at 9:25 AM

jaxman you're right. I shot myself in the foot when I wrote that you need it only during remote start. What I meant is if he was using the signal for a remote-start unit, then he needs it only while starting and after that the remote-start unit does not care about the existance of the tach voltage. But you're 100 percent right that the tach voltage is continuously needed for the engine to run. Sometimes I must read twice what I write before posting. Thanks for correcting!

Posted By: ivanca
Date Posted: December 15, 2004 at 9:41 AM

Thanks for every friend's answer.

I installed RS in Acura vigor 92. but burn the RS. I found the problem is the tach input part is burn. other features are ok.

So that is what I am thinking it is the high volts burn the RS.