95 Tach with 2003 TJ PCM?

[bottleworks]

JU is down, so I am asking here.

I installed a 4.0L engine/trans/xfer case from a 2003 TJ into my 95 YJ. I am using the 2003 TJ computer. I have it all wired up and running, but now I am working on the small things like gauges. The 95 computer had a tach signal out wire. the gauges for the 03 TJ get all their data from the PCM via a data stream. Any suggestions on how to connect the 95 tach to the 03 system?

 

[RichP]

After a quick look and according to my 97TJ manual the PCM supplies the signals thru a twisted pair cable coming out of the PCM as ccd bus c30 and c28, connector c102.
C30 d1 18vt br, c28 d2 18wt bk. That c30 and c28 supplies a whole bunch of other data signals to the other gauges too.
Personally I don't think you are going to get the factory YJ tach to work with the PCM. I'd go the other way and grab a signal off the dist, plug 1 or see if there is a tab on the distb for this. You will also have to be careful if you tap something, the load the tach puts on the signal strength could cause some issues with the PCM.

 

[aardvark4x4]

The YJ tach works from the YJ PCM so it's unlikeley to work. You mau have to use an aftermarket tach instead.