fliprayzin240sx
09-29-2010, 05:58 AM
Situation: S13 180sx redtop. Tach works fine with the stock ECU. We plug in a PFC for that engine (double checked the PN and it is for a redtop), the tach wont work on the cluster but the commander reads the signal fine.
How does the ECU see the tach signal? From what I know, the ECU and the cluster gets the same signal from the same wire (Yellow/Red wire iirc). It Ys off somewhere in the engine harness, one goes into the ECU and the other goes into a plug by the ECU that connects to the back of the cluster.
The cluster does not get its signal from the ECU correct? I'm pretty sure the ECU does not get the signal and then converts it to a signal that the tach can use.
I've checked continuity, and everything checks out. For shits and giggles, I've even replugged the stock ECU again to make sure it doesnt have a any wiring issue and the tach works again. Plug the PFC again, no tach.
How does the ECU see the tach signal? From what I know, the ECU and the cluster gets the same signal from the same wire (Yellow/Red wire iirc). It Ys off somewhere in the engine harness, one goes into the ECU and the other goes into a plug by the ECU that connects to the back of the cluster.
The cluster does not get its signal from the ECU correct? I'm pretty sure the ECU does not get the signal and then converts it to a signal that the tach can use.
I've checked continuity, and everything checks out. For shits and giggles, I've even replugged the stock ECU again to make sure it doesnt have a any wiring issue and the tach works again. Plug the PFC again, no tach.