Engine Misfire Archives - UnderhoodService
Deciphering Engine Misfire Codes

When the fuel/air mixture ignites, many factors must be met to pass a misfire monitor.

Detecting Misfire And Knock Conditions

Knock sensors are mounted on the block near the base of the cylinder head.

Diagnosing Misfires

What if there are no codes and a misfire is intermittent? This is where it gets complicated.

Mode $06 Misfire Diagnosis

Understanding why ‘Mode $06’ was developed and how it works to identify misfires.

ECM Damage

Engineers have devised two strategies that can be called the “immune system” for the electrical system.

Ignition Coil Output

To see inductance inside the primary windings, use an amp probe placed around the positive wire for the ignition coil.

Most Common Causes of Intermittent Misfire Codes

Misfires that turn on the check engine light and log a cylinder-specific fault code are the easiest to diagnose.

Understanding Misfire Events And Causes

Pre-ignition is very damaging because of two dynamics inside the cylinder.

VIDEO: Diagnosing Ignition Related Misfires

By performing these easy checks, you can determine if the spark plug wires are the problem or it is another component in the ignition system or on the engine. Sponsored by Blue Streak.

Understanding Misfire Events And Causes

When a spark plug fires, it is not an instantaneous ignition of all the molecules of air and fuel. When the spark kernel jumps between the two electrodes, the piston might be some distance from the top of the cylinder (this is usually described as degrees of crankshaft rotation).