So i'm trying to wire up my maft to my 1uz, and the only wire i was uncertian of was this one white wire that says is RPM signal in the maft manual. i'm supposed to connect it to the IGT wire on the 7m ecu, but since the 1uz has two ignitors i have a igt1 and igt2 so instead i connected it to the tach signal. so are IGT and the tach signal different?