VStar650CL wrote: ↑

Tue Feb 27, 2024 5:28 am

If you're getting an open for a good cylinder then you can't be checking the right pins. Make sure you're reading the diagrams correctly, single outline means you're looking at the connector face, double means you're looking at the back side where the wires enter. To make sure the pin-fit is also good, use an 0.024~0.026" safety pin or piece of music wire to probe the ECM connector from the face. It should resist slightly when you insert and remove it, if there's no resistance then the spring in the female terminal is weak or broken.

To clarify, open and short are diametrically opposite concepts. Open is "OL" on most meters and means 0% contact (infinite resistance), short is 0.00 on the meter and means 100% contact (no resistance). Short is only a problem if it represents continuity to the wrong place. The coil trigger wire should show "short" between the ECM pin and the coil trigger pin, that means there's continuity. It should not show "short" to the chassis or the ignition circuit, that means broken insulation and an actual short circuit. To properly check all aspects of the trigger circuit, it should show:

1) continuity, less than 1 ohm from the ECM connector to the coil connector
2 ) good pin-fit at both ends
3) OL between the trigger wire and ground wire at the coil connector
4) OL or at least 5K ohms between the trigger wire and 12V wire at the coil connector

When using an ohmmeter, always make sure all connectors in the circuit (in this case both the coil and ECM connectors) are unhooked. Ohming on an ECU driver circuit can blow up your very expensive ECU.