Yamaha VX: Three-Cylinder Runs Rough at Idle

On a three-cylinder you notice a weak cylinder immediately: the engine shakes. M-JET DIAGNOSTIC lets you activate each of the three ignition coils and injectors individually.

How to proceed

• Check the fault memory for ignition and sensor codes
• Activate ignition coils 1, 2 and 3 in turn
• Activate injectors 1, 2 and 3 in turn
• Watch idle values and teach the idle if needed

The comparison decides

If two cylinders respond normally and one does not, you have the candidate. Then you check connector and wire of that cylinder before replacing components. If all cylinders are in the normal range, false air, throttle valve and sensors come into question. If the throttle body was cleaned, learning helps calm the idle. The engine may only run with a water supply. After an oil change also check the oil level: overfilling can cost RPM on the TR-1 engines, and you will not see that in the app.

Related topics

• Yamaha VX with RiDE: Check Shifting, SCU and RPS
• Yamaha VX Won't Start: Check Relays, Pump and Ignition
• Yamaha WaveRunner Rough Idle: Diagnostics
• Diagnostics and fault codes for your Yamaha model
• All Yamaha WaveRunner diagnostics topics

Everything runs via app over Bluetooth, for Yamaha WaveRunners from model year 2002 to today. Learn more about the M-JET DIAGNOSTIC for Yamaha WaveRunner.