RPM wire on ecu harness?

I have a 90 DA with a pr4 ecu. I just put in a Apexi VAFC. I know its not good for tuning at all but I just wanted to see some parameters of a few things before I went to a fully tunable ecu. I ran into a snag. I can’t locate the RPM signal wire on the ecu harness. I’ve looked around and I heard one guy said it might be the B20 connector but it wasn’t it. Any help would be appreciated. Thanks in advance. I also have checked the ecu pinout diagram and it’s not labeled.

I believe if it has it, it would be near the resistor box. If not you can alsways tap off one of the wires going to the §§§§§. Not sure which one thou.

i found this out when i was puting in a kill switch on my friends teg on the distributor there is a plug that has two wires a black and yellow one and a blue one the skinny blue wire sends the signal to the tach i wired the switch wrong the first time maybe it will work