Story:
Before the swap and after the swap my tach was working fine. I know this because after the swap and gearing change in 5th gear at 100km/h I was at 4,000rpm. According to calculations it should be 64mph. Well we all know 100km/h is 62mph +/- 1 or 2mph is still within range so it is accurate.

Now in 5th gear 100km/h is still 4,000rpm, however, the tuner set vtec at 5800rpm but my tach reads between 6500-6800 at the switchover. This means that there is an issue with the tach i guess or even the signal. Can anyone shed some light or offer some troubleshooting solutions?

Thanks