Electrical 87 GT - Want Stock Tachometer to work with MSD Ignitiion

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njmatt415

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Aug 22, 2018

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NJ

Aug 30, 2018

#1

• Aug 30, 2018

• #1

Hi All,

Working with an 87 Mustang GT T-Top here. This car came with an MSD ignition which works great. It also came with a shift light that was never hooked up (and never will be). What I'd like to do is get the stock tach working on this fox to restore the retro feel. Please help! What is needed to get the stock/factory tachometer hooked up to the MSD? I did read that the MSD Tach Adapter 8920 is not required for my year. I'm not sure if this is true. If anyone could tell me how/where to hook up to the tach that would be awesome! Thanks.

matt

 

Last edited: Aug 30, 2018

Blown88GT

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Nov 13, 1999

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Palm Beach Gardens, FL

Aug 30, 2018

#2

• Aug 30, 2018

• #2

The MSD should not interfere with the tach, if it was connected properly. MSD should have instructions online.

 

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njmatt415

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Aug 22, 2018

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NJ

Aug 30, 2018

#3

• Aug 30, 2018

• #3

Thanks. I assumed the MSD was involved since all these adapters are floating around. I've since found the following info:

Tach Wire: Dark green with yellow stripe wire at ignition coil

 

Blown88GT

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Nov 13, 1999

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Palm Beach Gardens, FL

Aug 31, 2018

#4

• Aug 31, 2018

• #4

There are no tach connections on a Fox body.

 

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njmatt415

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Aug 22, 2018

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NJ

Sep 3, 2018

#5

• Sep 3, 2018

• #5

I should mention this car had been converted from FI to carburated

 

a91what

SendMeUrDataLog

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Apr 6, 2011

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Sep 3, 2018

#6

• Sep 3, 2018

• #6

thats the first thing you should have mentioned... how much of the factory wiring is still remaining?? the tach is pulsed from the negative side of the stock coil. If the wiring is no longer there you will have to take the tach out from the MSD or the negative coil wiring and extend it to where the factory wiring was cut.

 

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njmatt415

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Aug 22, 2018

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NJ

Sep 5, 2018

#7

• Sep 5, 2018

• #7

Thanks. I was able to locate the signal using an external tach to the ignition coil and is steady! So now I would just need to run a wire from the negative side of the coil to the green and yellow stripe wire?

 

a91what

SendMeUrDataLog

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#8

• Sep 5, 2018

• #8

yes that should work

 

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njmatt415

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Aug 22, 2018

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NJ

Oct 6, 2018

#9

• Oct 6, 2018

• #9

I was able to get the tach to work. It was the POSITIVE side of the ignition coil TO the green and yellow stripe wire.

 

a91what

SendMeUrDataLog

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Oct 6, 2018

#10

• Oct 6, 2018

• #10

What color did you tap into at the coil? the stock tach is driven off the negative side of the coil.

 

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njmatt415

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NJ

Oct 6, 2018

#11

• Oct 6, 2018

• #11

That could be why. This is coming from an MSD coil, not stock. Either way, pick a side, one of the two will work!
Thanks for the tips again!

 

M

mustang50notch

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Jul 2, 2021

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Abingdon Md

Jul 8, 2021

#12

• Jul 8, 2021

• #12

So my 87 notch was a 4 banger. It has aftermarket tach and msd box. What do I have to do to get stock tach to work.