Installed new coil, now the tach acts funny
I have the exact same problem you’re having with my tach. I switched coils and had horrible issues with my tach directly after. Everything seemed to read right but I got erratic readings after 2000 rpm. I’m no expert but I did solve the problem.
I saw a video auto meter put out about needing to put a 10k ohm 0.5W resistor in the wire that connects to the negative side of the coil. I did this and it immediately made my tach work perfectly!
NOTE! The 10k resistor is not the be all and end all of solutions. I think different resistors should be used for different coils of different power capabilities. I tried to hook up a Blaster 2 coil to this system and it only worked up to 2500rpm and read erratically. A different resistor needs to be used.
EDIT: Okay, so the reason the 10k ohm resistor worked for me was, the secondary resistance for my coil is 10k ohm. I found this out by visiting Jegs.com, locating my coil and finding what the “secondary resistance” rating was on the product description was.
I have the exact same problem you’re having with my tach. I switched coils and had horrible issues with my tach directly after. Everything seemed to read right but I got erratic readings after 2000 rpm. I’m no expert but I did solve the problem.
I saw a video auto meter put out about needing to put a 10k ohm 0.5W resistor in the wire that connects to the negative side of the coil. I did this and it immediately made my tach work perfectly!
NOTE! The 10k resistor is not the be all and end all of solutions. I think different resistors should be used for different coils of different power capabilities. I tried to hook up a Blaster 2 coil to this system and it only worked up to 2500rpm and read erratically. A different resistor needs to be used.
EDIT: Okay, so the reason the 10k ohm resistor worked for me was, the secondary resistance for my coil is 10k ohm. I found this out by visiting Jegs.com, locating my coil and finding what the “secondary resistance” rating was on the product description was.