Top Tips: Misfires and ignition coils
coil packs came along
the modern coil pack and ignition coil technology, most will remember
or have heard of the 'distributor' within an engine.
This device was simply a rotating arm that passed over a number
of metal contacts as it rotated. As it passed over each contact,
the high-voltage from the ignition coil would be 'distributed' to
the correct spark plug to generate the spark.
move to coils and coil packs
engines have done away with the distributor, instead using low-voltage
electronic signals from the engine-management system to trigger the
signals are sent to an individual coil for each spark plug. These
coils act as a transformer to generate the high-voltage required
to operate the spark plug.
The coils convert the 12 volt signal from the car internal supply
to the 25,000 to 30,000 volts needed by the plug to create the spark.
using individual coils, the need to 'switch' high voltages is removed.
This was often a source of trouble in earlier engines - especially in
damp conditions, as I'm sure many will remember.
and coil packs fail for a variety of reasons.
This often manifests itself as a poor idle, intermittent misfires
at low engine speed or a total failure of spark in the affected
diagnostic tools are key to helping identify the source and location
of the fault. They will often not only identify that the fault is present,
but also which coils have failed.
fault codes pointing towards possible ignition coil faults are,
P0351 - Ignition coil A, primary/secondary - circuit malfunction
- Cylinder 3 - misfire detected
- Random/multiple cylinder(s) - misfire detected
coils and coil packs are readily available and are generally
quick and easy to change.
setups can vary between cars, but there are 3 main types:
where separate coils are located very near to or directly on top
of each spark plug (known as direct ignition or coil-on-plug)
where the coils are mounted together in a single 'coil pack'. This
block is mounted away from the spark plugs and is attached to them
with HT leads
again where the coils are mounted together as a pack, but the cassette
generally fits directly onto the spark plugs
our online application
list for your car - we currently stock replacement coils and
packs for over 600 car models.
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