What causes a spark plug to misfire intermittently?
Intermittent ignition misfires can be caused by faulty spark plugs, spark plug wires, ignition coils and ignition coil drivers located in the ECM. Some intermittent misfires can be more easily detected if a scan tool displays an individual cylinder misfire count in its datastream, or monitors coil activity…
What causes a cylinder to have a misfire code?
When you have a misfire code for a particular cylinder, you can focus on one of three things: an ignition problem, a fuel injector problem or a compression problem. Every time a spark plug fires, the spark burns a few molecules of metal off the plug’s electrodes.
What causes an intermittent misfire on a V-type engine?
In either case, the misfire might occur only under specific operating conditions. Engines equipped with variable valve timing (VVT) generally cause misfires on a single cylinder bank of a V-type engine if a cam phaser or solenoid intermittently sticks in position.
Can a coolant leak cause an intermittent misfire?
Since misfires caused by coolant leaking from cylinder head gaskets often depend upon engine temperature, they can become very intermittent. In most cases, the diagnostic tech must pursue intermittent ignition faults by visually inspecting parts for spark perforation or carbon tracking, or by using a labscope to monitor ignition activity.
Intermittent ignition misfires can be caused by faulty spark plugs, spark plug wires, ignition coils and ignition coil drivers located in the ECM. Some intermittent misfires can be more easily detected if a scan tool displays an individual cylinder misfire count in its datastream, or monitors coil activity…
What does it mean when a cylinder is misfired?
If your scan tool’s misfire history indicates multiple cylinder misfires, focus on the cylinder with the most misfire counts. The misfire counts on adjacent cylinders are often “sympathetic” misfires that will often disappear when the primary misfire is repaired.
How to diagnose an intermittent engine misfire?
When diagnosing intermittent misfires, don’t forget to look at pending codes for indications of an individual cylinder misfire. If your scan tool’s misfire history indicates multiple cylinder misfires, focus on the cylinder with the most misfire counts.
Since misfires caused by coolant leaking from cylinder head gaskets often depend upon engine temperature, they can become very intermittent. In most cases, the diagnostic tech must pursue intermittent ignition faults by visually inspecting parts for spark perforation or carbon tracking, or by using a labscope to monitor ignition activity.