Can someone tell me where the easiest place to splice into the Tach input wire is? Preferrably inside the car without removing the dash cluster. Hopefully someone knows which plug it's supposed to be in around the drivers left foot?

Thanks in advance.

http://www.MisRed.com/pix
'87 Mazda RX-7 w/Buick Grand National Drivetrain

 

I have no idea which wire it is, sorry. But after looking at your photos; I can't believe that you would even hesitate for a second, to remove the dash cluster. You have basically rebuilt the entire car, might as well take off the dash to. The wiring diagram is in the factory service manual; you can find it at www.fc3s.org

 

I have already removed the dash cluster once to recalibrate the tach for a 6cyl. I am hesitant to remove the dash cluster again because the plastic is very brittle. I have already repaired the bottom part of the dash cluster so it's again tightly attached on to the dash. Before the blinker switch and head light switch were essentially flopping around....

Thanks for any input.

 

Ok, looking over my wiring diagram, it's a Yellow/Blue wire running from the front coil pack all the way into the dash. Can't confirm for you, my car isn't ready to start yet.

PaulC

 

I don't exactly know what you're trying to accomplish...

If you're doing an engine swap, this eliminates the fact that the stock coils and ignitors (both leadings and trailing packs) have existing tach signal wires right off them...

If you're dropping in a non-rotary, don't you need a tach adapter spliced into the distributor???

Why are you messing with the stock instrument cluster for you?&nbsp Are you trying to get that to work or something?&nbsp It really sounds like you're trying to add an aftermarket tach to the car with a non-rotary engine swap...



-Ted

 

This jpg along with the one following. Look for the CO-3 plug and the wire coming off the tach.

 

Follow up jpg: The tach wire is the yeller and blue wire in the CO-3 connector as shown in the two jpg's.

 

Here's where the yeller and blue, YL, wire comes out of the coil assy headed for the CO-3 connector in the above jpgs:

 

Thanks for the info. I found the Yellow/Blue wire and tapped into it. Works great.

BTW, I am using the stock gauge cluster (all gauges now function) with the Buick DIS igintion system. There is no distributor, just a tach lead coming out of the coil pack.

Also, if you were wondering, I had to adjust the pot screw on the back of the Mazda tach until the RPM's were accurate with the actual engine RPM. Thanks again.