Thursday, November 7, 2013
What Is a Toyota Camry Coil Pack
The name "Camry" is an anglicized interpretation of the cars original nomenclature "Kanmuri," which means "crown" in Japanese. Little could Toyota have known when it introduced the car in 1982 how appropriate that name would become, as the Camry would eventually be crowned the king of compact sedans in America.
Ignition Function
The basic purpose of any automobiles ignition system is to ignite the air/fuel in the cylinders. Three basic parts comprise the ignition system: the triggering mechanism that sends energy to the spark plugs, the ignition coil that amplifies the triggering energy to create a powerful spark and the spark plug that receives that energy to make the air/fuel mixture detonate. The shorter the distance between the ignition coil and plug, the less energy the system loses through resistance in the wire.
Coil Pack Ignition
Ideally, a spark plug should be connected directly to the ignition coil so that every bit of the coils energy goes into creating a spark. This wasnt practical on older, distributor-driven cars; the distributor itself was the weak link in the system, so the gains would have been minimal. It wasnt until the mid-1980s that computers and magnetic sensors were cheap enough, powerful enough and sophisticated enough to detect crankshaft position and trigger the coil without a distributor. Once these were mass-produced, manufacturers began using a computer to trigger multiple coils in a "coil pack." Each coil provided energy to two cylinders.
Direct Ignition
Direct ignition is an evolution of coil-pack ignition and uses a single coil mounted directly to the back of the spark plug instead of one coil for every two cylinders. Direct ignition is the most theoretically perfect ignition possible with todays technology, offering a very powerful, computer-controlled spark without relying on a single moving component. The Camry doesnt actually use a coil pack; it has direct ignition with one small coil-pack-style coil per cylinder.
Failure
One of the direct ignition systems strongest trump cards is that it uses solid-state technology. There are no moving parts to wear out; even the crankshaft position sensor is fully magnetic, so it cant wear out through normal use as a mechanical component would. Aside from computer failure, the only way that a direct ignition system can fail is if the coil itself internally shorts out or something happens to the wiring between the coils and the computer.
If you suspect ignition coil failure, simply unplug the wiring harness from the top of the plug and see if the engine changes pitch or idle quality. Of course, the Camrys on-board diagnostics system will already have detected a coil malfunction and triggered a check engine light, so this might action might not be necessary.
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