Need wiring help on YJ Tach to CJ wiring

danheit · 12-30-2008, 08:22 PM

Hey guys, need a little help. Right now I am rounding the final bend on the CJ refreshening, and am down to the wiring.
A little background for those of you that have not seen my build, I swapped the YJ tub onto my CJ frame, and am using the CJ front clip, and all CJ wiring harness. I have chosen to use the YJ dash panel ( I know, it's sacreligious, but it's all I have and $$ is too tight right now for sheet metal) that I already have, but retain most of my CJ guages. I am losing the stock speedo in place for the one out of the YJ, as it is a mechanical speedo too. I just hope it will work with my turbo 400 trans....; I am using the stock volt meter and oil pressure guages, but will be adding in a fuel guage and temp guage to the instrument cluster, as well as the factory clock still being used somehow. Right now I am down to having to figure out the tach wiring.

The tach I am using is the stock 92 YJ 6cyl tach, but I am trying to wire it into my 79 CJ7 w/304 wiring harness. I have no haynes manual, as it is stuck in storage.

Long story short, has anyone done this, or can it be done? The tach wiring for the CJ is for a series tach. The YJ wiring I am not familiar enough with, and I only have the tub harness, not the engine harness, so I can't follow where everything goes. The YJ tach has 4 wires. Orange and Black which go to the lighting, and a green and white IIRC. Anyone know where or how these will splice in?

**John Strenk** · 12-31-2008, 04:58 AM

I suspect this is wired like a conventional tach with one lead going to power and one going to the (-) on the coil. I'll need to locate a YJ schematic to be sure.

Are you aware YJ fuel sending unit is the opposite of the CJ so your fuel gauge will read backwards?

danheit · 12-31-2008, 07:37 AM

yeah, I am going to use an aftermarket fuel guage, and the YJ sending unit/tank.
Thanks for the info on the wiring setup. Anyone have any idea of which wires go where?

danheit · 12-31-2008, 07:38 AM

yeah, I am going to use an aftermarket fuel guage, and the YJ sending unit/tank.
Thanks for the info on the wiring setup. Anyone have any idea of which wires go where?

**John Strenk** · 12-31-2008, 08:24 AM

Hard to read but it looks like Green goes to the ign coil.

Ignore the others stuff on this page. It's how to hook a CJ tach up to a YJ Engine.