Tach Filter Question

[csfields]

I know this has been burnt up on other threads. I am still not finding what I am looking for. I am installed a factory tach, which was obviously junk, didn't know it at the time, so I purchased a new repo tach from Classic Parts and stated that I had to use a tach filter. I have read threads where some say it's needed etc. I figured since they recommended it wither for functional purposes or for a sale, I would use it. I just need the sime question of how to hook it up exactly. The tach like a factory one has the 12+ and coil terminals on the back along with a added ground post. I am just curious as to the proper way to get the filter inline with all this. Not quite sure I understand the directions. Call me stupid, just need some direction. I have managed to build this truck from the ground up, but stumped here.

I pulled pictures from other posts to show filter and directions.

[csfields]

I know where the ground goes. I am thinking that the yellow goes to coil post on tach and that the red leads back to the coil itself? Do you all think this is accurate?

[No8Easy2]

whats up Casey? yeah that's a head scratcher! the only thing I'm not 100% on if it go inline with the tach signal or just piggy back on the tach itself

this is the way i would do it

black to ground
red to (-) coil
yellow to tach

did it come with any other fittings that might help figure it out?

Chris

[Zeke's Garage]

Yes, the filter needs to be inline between the coil, red wire to (-) on coil, and yellow to the tach input on the tachometer, and black goes to ground.
The filter is used to cut down on 'rpm noise' on the radio coming from the coil. With a modern radio, or radio block-off plate, I doubt you even need one.

[TBONE1964]

http://www.marshallinstruments.com/pdf/37.pdf


The link has better instructions.

[71K20chevy]

I hooked my factory tach to my HEI without the filter and it works just fine.

[csfields]

Originally Posted by TBONE1964

http://www.marshallinstruments.com/pdf/37.pdf


The link has better instructions.

Thanks guys for alll the help. These instructions really make it easier to understand. According to these instructions you can wire it backwards for increase filtering? I will try the standard way first and go from there. Thanks again for all the input. Sometimes you just get unsure of yourself and need a second or third opinion.

[TBONE1964]

Originally Posted by csfields

Thanks guys for alll the help. These instructions really make it easier to understand. According to these instructions you can wire it backwards for increase filtering? I will try the standard way first and go from there. Thanks again for all the input. Sometimes you just get unsure of yourself and need a second or third opinion.

That's what we are here for Casey. Glad it helped you.

Keep up the good work on the truck. It is looking great.

Take care,
Tom