How to properly read a tach signal

Home / the12volt's Install Bay / Car Security and Convenience / How to properly read a tach signal (

Topic Closed)

Welcome Guest :)

Members

< Prev Topic Next Topic >

Illuminatrix

Member - Posts: 23

Joined: September 21, 2003

Location: Canada

Posted: October 27, 2003 at 11:43 PM / IP Logged

Can someone tell me how to read the tach signal properlly. My Tester has 200mv and 500mv in AC mode. What should my tach wire read ?? and does voltage go up or down with a rev of engine ??

Thanks again. I am destined not to use voltage mode.

Cheers

Travis

NowYaKnow

Gold - Posts: 1,217

Joined: December 18, 2002

Posted: October 28, 2003 at 5:00 AM / IP Logged

Here's how I read tach wires..Take your meter. Put one side to ground and the other side to your tach wire. Set your meter to AC Volts and start the car. The wire shouldn't read anything with the car off, and then just up to like 1 - 1.5 volts with the car running. When you rev up the car it should jump to around 2 - 3 volts. That's how I read all my tach wires. The exact voltage numbers aren't too important you just want to see some AC voltage that rises when you rev it. Depending on the car they all read a little differently so yours may sit at like .5 volt and rise to 1 volt or may sit at around 2.5 volts and rise to 3 there's really no set numbers. As for finding the tach wire normally you would follow the spark plug wires back to the coil packs and it will be one of the wires coming off of that module. Sometimes accessing that isn't possible though so you may have to look elsewhere..Good luck,

Mike

Illuminatrix

Member - Posts: 23

Joined: September 21, 2003

Location: Canada

Posted: October 28, 2003 at 8:10 AM / IP Logged

So if my tester has 200mv and 500mv settings for AC what would it read. Sorry for such a dumb question I just want to be sure.

Thanks

Travis

sid2k

Member - Posts: 6

Joined: October 17, 2003

Location: United States

Posted: October 28, 2003 at 8:15 AM / IP Logged

200mv

Illuminatrix

Member - Posts: 23

Joined: September 21, 2003

Location: Canada

Posted: October 28, 2003 at 9:03 AM / IP Logged

Ok I am dumb so at 200mv what should my tach wire read ????

Thanks, I want to get this dang thing set up properly.

Cheers

Travis

derek123

Copper - Posts: 163

Joined: October 09, 2003

Location: Canada

Posted: October 28, 2003 at 11:21 AM / IP Logged

You may end up blowing that meter.

some tach signals are higher than 12 volts.

are you sure its 500 mV ?

from what your saying even a poor tach siganl ( less than one volt) is going to be too much for your meter.

also, NowYaKnow pretty much nailed it on how to test with a DMM, one thing missing is that some true tach references will keep the same voltage ( as RPM increases) but the frequency of the siganl increases instead. you need a pretty spiffy meter to read that though.

Illuminatrix

Member - Posts: 23

Joined: September 21, 2003

Location: Canada

Posted: October 28, 2003 at 1:03 PM / IP Logged

Will a DC 12 Volt battery test on my meter work to test this signal.

Sorry, you can NOT post a reply.
This topic is closed.

Printable version

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

Search the12volt.com

Follow the12volt.com

Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

How to properly read a tach signal

Sorry, you can NOT post a reply.This topic is closed.

Sorry, you can NOT post a reply.
This topic is closed.