tbi tach wires

[michael0584]

I am adding a tach to my 87 with tbi, what wire do I use for the signal for the tach. I know where it is on one with an hei distributor, but I don't know for tbi. Is there a wire already under the dash or do I run one? Also what color wire under the dash is for the instrument lights? Also how about a keyed power source wire. I guess I'm getting a little lazy, I could use a test light and find all this, but typing is much easier...

 

[doonjumper]

I guess I'm getting a little lazy, I could use a test light and find all this, but typing is much easier...

Too many variables.

 

[4X4HIGH]

The TBI trucks have a white wire coming off the ignition coil which is for a tach, you'll have to run a wire from your tach to this wire and either use the appropriate connector or cut off the connector and solder/butt connector crimp the wires together.

 

[michael0584]

Is that the wire the ecm uses to determine rpm?

 

[BoondocK5]

...

 

[4X4HIGH]

Is that the wire the ecm uses to determine rpm?

It is the reference signal wire for the tach. Your tach should have a red (keyed hot), black (chassis ground) green (reference singal that connects to the white wire on the ignition coil) and a white (dash lights).

 

[BoondocK5]

It is the reference signal wire for the tach. Your tach should have a red (keyed hot), black (chassis ground) green (reference singal that connects to the white wire on the ignition coil) and a white (dash lights).

Thanks Scott! Good info right here.

 

[michael0584]

It is the reference signal wire for the tach. Your tach should have a red (keyed hot), black (chassis ground) green (reference singal that connects to the white wire on the ignition coil) and a white (dash lights).

Thank You!!