You have heard it said before that the internal combustion engine is basically an air pump. The internal combustion engine has never been 100% efficient, but recent technology has improved the engine on a major basis with the addition of intake runner control systems, variable valve timing systems and turbo and turbo-equipped engines.
A friend of mine and automotive instructor by the name of John Forro once stated that 80% of the emission codes that light the malfunction indicator light (MIL) can be easily diagnosed from the generic or global side of the scan tool, and I would have to agree with him.
For those of you who can recall when the manufacturers first came out with the port fuel injected systems, you will remember it wasn’t long before we saw some predictable problems surface on these vehicles, such as olefin and diolefin buildup on the pintle area of the injector causing a restriction.
Coil-on-plug, or COP, features an individual coil dedicated at each cylinder, with the COP connected directly to the spark plug, eliminating the need for plug wires. Due to variances in COP design among auto makers, spark control, troubleshooting and diagnostics can vary. This article is intended to provide education relative to COP, along with tips and precautions regarding testing and diagnosing engine misfire issues.
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