Have a 65 GT350 with original tach using dual points distributor and original yellow top coil and the famous pink resister wire which comes from back side of key thru firewall to Battery side of coil. Single Black wire from dual point distributor goes to Distributor side of coil. Red wire from the 65 Tach also connects to Distributor side of coil for signal and all is well.
An tired fooling with points and dwell and want to incorporate a Pertronics Ignitor I into the system.
Removed dual points plate and black wire to Distributor side of original yellow top coil.
Left red lead from firewall that connects ignition pink resister wire to Battery side of coil connected.
Left red tach wire that went to Distributor side of coil disconnected.
The Pertronics Ignitor I has two wires, red and black. Red wire goes to Battery side of yellow top coil and black wire goes to Distributor side of same coil.
Engine fires and runs great.
However, when I reconnect the original 65 red tach signal wire to the Distributor side of the coil, the tach does not provide accurate reading for RPM. Needle moves but not at right RPM.
Any idea what I am doing wrong here? Car is scheduled to head to Florida tomorrow morning and still having issues getting tach to function. Pertronix says Ignitor I will work just fine using the pink resister wire voltage.
Any help at this hour is greatly appreciated.
Martin
I don't know if there is a fix for the tach. I had the same problem on a Chevy with an aftermarket tach. I talked to them at the time (they were still here in Covina) the guy said it was due to the trigger voltage and different dwell. I went back to points.
I suspect if you got your voltage from the ignition switch before it goes through the resistor wire instead of at the coil then your problem with the tach will most likely will go away . You will also get a full 12V to the pertronix which is more desirable. The resister wire made into the circuit knocks the voltage way down. You could also put the point plate back on to solve the problem in the short term .
I sent you wiring instructions. I'll be stateside this evening. If the written directions I provided are confusing I'll give you my phone number and walk you through.