You may not have the wire from the ignitor to the tach. I had to run one in my 85 pu. I went to the junk yard and got a similar toyota electrical connector and pulled a pin, then attached the pin to my new to-be-installed tach wire. The pin then was inserted in the correct pin location of the instrument cluster connector, pin location found in the wiring diagrams. (If you need it I can get it for you later) I ran the wire out of the firewall down the inside left fender and finally routed it to the - terminal of ignitor. This and the oil sender is all I had to do to put a tach cluster into a non tach cluster 85.