How to test for faulty ignition

Yamaha FJR Motorcycle Forum

Help Support Yamaha FJR Motorcycle Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Tonyducks

Active member
Joined
Sep 26, 2009
Messages
31
Reaction score
0
Location
San Diego
After my bike just didnt even seem to have life last night. Checking battery and fuses. My gut is telling me it is a faulty ignition that soaked up some rain water and may have corroded some stuff.

I have a multi meter and have disconnected the connection underneath tank for the ignition. But how would I test to see if it really is the igniition using the multimeter.

Thank you everyone. Peace and truth

 
A quick test of the ignition is easy--all you need is a test light.

1. Remove the 2 wires at one of the ignition coils (doesn't matter which one).

2. Connect the test light alligator clip to one of the wires and the pointy end of the test light to the other wire.

3. Crank the engine over while watching the test light.

If the test light flashes (or flickers dimly) the following are working: Crank sensor is sending a signal to the ECU, the ECU has power and is processing the crank sensor's signal and sending a trigger signal(ignition pulse) to the ignition coil. This test also check the wires associated with each of these components.

If the test light doesn't flash, check for power at the ECU (find the wire at the ECU that should have battery power with the key on). Check the power source to the ignition coil (maybe a fuse?)

To check the crank sensor find the 2 wires from the sensor at the ECU. Unplug the ECU connector and use a multimeter set to read AC volts. Connect one lead to one of the crank sensor wires and the other lead to the other crank sensor wire. Crank the engine over while watching the multimeter. If the sensor is working you should read a small AC voltage (maybe 1 to 3 volts AC). This tests the sensor's operation as well as verifying the integrety of the wires from the ECU to the sensor.

 
Top