Hey all. I’ve been having an issue with my tach not working on my 2000 civic. When I first got the car 3 years ago, it had a b18c1 in it and the tach worked fine. The dizzy took a dump on me and I had to put in a new one. When I did the tach stopped working. I swapped out the coil from my old one and it started working again. Fast forward to this year, I swapped in a built b18c1 with a new distributor and the tach stopped working again. I didn’t worry about it at the time. Now my alternator went out and I was in the process of replacing it. When the alternator was unplugged and the belt was off, I had to start it to move it real quick. I noticed my tach was working again? I parked it and the next day came and started it again and the tach was still working. I then replaced the alternator and hooked it all back up. But now my tach doesn’t work anymore. Is this a bad ground? I’m completely lost as to how my alternator could affect my tach.

 

Not sure how you can verify if your tach is working when you're in the progress of removing an alternator but for this particular yr the tach gets a signal from the obd2b ecu. If you have a different ecu than someone probably wired the tach directly to the distributor.