# Tach wiring help



## muccman (Aug 24, 2003)

*Aftermarket Tach wiring help*

Hey guys, I just bought a cheap tach for my car because it doesnt have one. I was wondering if you guys could give me a heads up on where to hookuip the wires ( location etc ).


Green Wire: To the negative side of the coil ( where is that )

White Wire: Connect to any dash panel light wire for illumination ( where 
would i tap into for this one ).

Red: Ignition on so that voltage is supplied with engine running ( im thinking to the red wire off my cd player.. cuz its the same thing )

Black: Ground ( well duh.. ill find htat one  )


Im going to be mounting it between my speedometer and my gas guage so that its right infront of the guage cluster.. will be running the wires through the steering column for easy access purposes. So can someone tell me where the greem white and red wires could be hooked up to? Thanks


Marc


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## muccman (Aug 24, 2003)

c'mon.. someone has to know how this thing hooks up.. please :cheers: :fluffy:


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## recycled_toddler (Feb 4, 2004)

muccman said:


> Hey...I was wondering if you guys could give me a heads up on where to hookuip the wires...
> 
> 
> Green: Negative side of coil (Where is that?)
> ...


*Red Wire:* First off, I recommend against tapping directly off an accessory like a CD player; You could open a Pandora's box that might cost you. Use a voltmeter at the fusebox (Set it to accommodate 12 volts DC, ground the black probe and use the red at the fusebox), you can try to tap off a keyed circuit; Find out which circuit turns on and off with the key and tap into it. You're better off that way.

*White Wire:* You might find a wire that feeds a light bulb to another gauge; Ground your voltmeter black lead and turn your parking lights on; Using a sharp voltmeter red probe, pierce the suspected wire you want to tap off and adjust your dash illumination dimmer; If the voltmeter drops/rises as you adjust accordingly, there's your wire. Tap into 'er.

*Green Wire:* First off *(Very important!)*, go to *Radio Shack* and buy a 2 kilo-ohm, 1/4-watt resistor. Then, solder one end of it to the end of your green wire. Shrink-tube or black-tape the hell out of the resistor and 1 inch of the green wire sheath, leaving one inch of the free end of your resistor exposed. Route the end of your green wire through the firewall, along the engine bay to the coil and look on the coil for two terminals with small wires (I'm assuming your Sentra has a modular plug for the coil). Remove the plug and turn you ignition to *run*. Then, using your voltmeter, ground the black probe and use the red probe to find which of the two wires of the plug is 'hot'; The wire you want to use is the one that doesn't register voltage. Tap into 'er, and you should be OK. Rehook everything, fire 'er up and make sure it does the job. *Ergo!* :cheers:


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## FlippyBoy (May 23, 2003)

what is the resistor for? i didnt use one when i installed mine - ill try to post pics of it later.


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## Gsolo (Sep 11, 2003)

FlippyBoy said:


> what is the resistor for? i didnt use one when i installed mine - ill try to post pics of it later.



yeah...resistor?


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## muccman (Aug 24, 2003)

yeah.. whats the deal with the resistor? If its because you think that it might read higher because i have a 4cylinder, there is a switch in hte back of the tach that has a 4-6-8 selection on the back.. i just put it to the 4 cylinder model.. and there's nothing in the instructions that say about putting a resistor in the wiring going to the coil.. so do tell why the resistor


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## RiceBox (Apr 30, 2002)

Do a search. I've answered this question ATLEAST 3 times


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## muccman (Aug 24, 2003)

ok, i searched and found in some places that people tapped a turquoise wire on E16s... would this be the same with my E16i? I think i was looking at webfoot's pictures and found an actual picture of where he sliced into : http://community.webshots.com/photo/73449102/73449920hqtDvG 

would this be it?

Thanks a lot RiceBox


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## muccman (Aug 24, 2003)

ok, i went and took a picture of hte coil with my digital camera ( pardon the shitty quality ). There seemed to be a black/white wire, blue wire and green wire coming from the coil ( see picture ). Now the instructions say to run the wire to the negative terminal on the coil. What wire would I have to hook it up to to get my tach to work? #1 - green, #2 - blue, #3 - black/white.. there's a fourth one but i cant really remember the color.













EDIT:::

Should I take it as the blue wire is the one i connect to? Look here : http://community.webshots.com/photo/73449102/73449810HDYIOz 

and i quote:



> Tach transistor
> Here is some kind of power transistor that connects to the coil. this is where RacerX and others connected their tach signal. Connect to the blue wire. This component is abundant at the jy.



Blue wire?


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## Gsolo (Sep 11, 2003)

all of you honestly have me completely lost.


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## muccman (Aug 24, 2003)

OK, lets try to make this comprehendable for ya GSolo 


I need to know where to hookup the tach signal wire. According to Webfoot's pictures, he said the BLUE wire would give the signal for the tach. I'm just wanting to know if its true. If not, is there a way to check to see what wire gives off a tach signal?


Marc


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## Gsolo (Sep 11, 2003)

muccman said:


> OK, lets try to make this comprehendable for ya GSolo
> 
> 
> I need to know where to hookup the tach signal wire. According to Webfoot's pictures, he said the BLUE wire would give the signal for the tach. I'm just wanting to know if its true. If not, is there a way to check to see what wire gives off a tach signal?
> ...


i'm lost on why need resistor. But just use a voltmeter to check.


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## Gsolo (Sep 11, 2003)

RiceBox said:


> Do a search. I've answered this question ATLEAST 3 times


i searched and found nothing. But i'm thinking all it would do is probably keep it from being jumpy...but most good tachs have something built in, and usually the signal isn't that bad


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## Popkorn (Nov 16, 2003)

muccman said:


> OK, lets try to make this comprehendable for ya GSolo
> 
> 
> I need to know where to hookup the tach signal wire. According to Webfoot's pictures, he said the BLUE wire would give the signal for the tach. I'm just wanting to know if its true. If not, is there a way to check to see what wire gives off a tach signal?
> ...


Look at all the pics. This one http://community.webshots.com/photo/73449102/73451347DhAWfa is another angle.


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## minute rice sentra (Mar 21, 2003)

Ok the blue wire(not my spark plug wire  ) connected to the coil should be your negative.

Edit: hmmm... looks like everyone's got different ignition setups than me, that's wierd.


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## muccman (Aug 24, 2003)

minute rice sentra said:


> Ok the blue wire(not my spark plug wire  ) connected to the coil should be your negative.
> 
> Edit: hmmm... looks like everyone's got different ignition setups than me, that's wierd.



minute, thats the same setup as me.. if you take a look at the grey connector with the black and blue wire coming out of it, the blue wire goes to the bottom of the coil and the black one goes into the black box next to it. So is it safe to assume that the blue wire going to the bottom of the coil is the wire that would have the signal for my tach?


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## minute rice sentra (Mar 21, 2003)

I just went and double checked, the top wire on the connector(black) is positive and the bottom wire(blue) is negative. I don't know about any resistor though.


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