INCREASING IGNITION SYSTEM SALES
Many veteran parts professionals
remember when replacing contact points, condensers and spark plugs was
required annual maintenance. But during the 1970s, electronic ignition
systems did away with all that.
Advances in engine fuel control
and the introduction of unleaded gasoline also began extending the
service life of most spark plugs well into the 30,000-mile range. By
the early 1990s, auto manufacturers had introduced long-life spark
plugs with extended service lives of at least 100,000 miles. When the
“100,000-mile tune-up” became commonplace, many throughout the
automotive service industry predicted that ignition sales were becoming
a declining market.
A PROFITABLE MARKET
most jobbers, perception is not reality. By the 2000 model year, it
seemed like ignition parts sales were, indeed, becoming a declining
market for many jobbers and retailers. But we can’t analyze markets by
comparing apples to oranges. The apples in this case are the relatively
inexpensive ignition parts of a decade ago and the oranges are the
expensive ignition parts of today.
To illustrate, conventional
distributor ignition systems used one coil to supply spark to all of an
engine’s cylinders. Modern waste-spark distributorless ignitions use
one coil per two cylinders, with a typical V6 engine having three coils
and a V8 having four coils. Coil-on-plug designs incorporate one coil
per cylinder. Simply put, modern technology has, depending upon
application, increased potential ignition coil sales by multiples.
many veteran parts professionals recall when the wholesale price for an
average spark plug application was slightly less than a dollar. Today,
the average wholesale price of a long-life spark plug can be $10 or
more for many applications. So, when we’re talking about the ignition
market, let’s talk about dollars and cents instead of unit sales.
PRIMARY AND SECONDARY IGNITION DEFINED
understand the ignition market, we need to understand the language.
Primary ignition parts like crankshaft sensors, camshaft sensors,
magnetic pickup coils for distributor ignitions and ignition modules
are those that operate at or near battery voltage. The ignition coil is
an exception because it operates with a primary and secondary winding,
with the primary winding operating at 12 volts and the secondary at
12,000 to 60,000 volts.
It’s important to understand that the
replacement of primary ignition parts isn’t part of any auto
manufacturer’s normal scheduled maintenance. While some shops might
replace primary ignition as a preventive measure on older vehicles,
most primary ignition is replaced only when the original component
In contrast, secondary ignition parts are expendable units
because the secondary winding of the ignition coil generates a
high-voltage spark that ranges between 12,000 and 60,000 volts,
depending upon application and operating conditions. This extremely
high voltage wears away spark plug electrodes and tends to burn through
or erode secondary ignition parts like ignition coils, distributor
caps, rotors and wires.
CATALYTIC CONVERTERS AND IGNITION MISFIRES
most important rationale to selling quality ignition parts is to
prevent an engine misfire from damaging expensive catalytic converters.
Because catalytic converters are designed to burn gasoline and other
hydrocarbons left over from the combustion process, an ignition misfire
can cause excessive amounts of hydrocarbons in the form of unburned
oxygen and gasoline to enter the catalytic converter. When this
happens, the converter core will melt, causing the check engine light
to illuminate and the vehicle to fail an exhaust gas emissions test.
when serving your amateur or professional mechanic, always remind them
that all modern ignition products are designed to prevent potential
misfires from damaging the vehicle’s expensive catalytic converter.
start by saying we should think twice before we reduce our
profitability by substituting conventional spark plugs for the more
expensive long-life spark plugs. Sure, the customer’s mistaken belief
that he’s saving money might be driving the sale, but the long-term
consequences might include a steel-shell spark plug permanently seizing
into an aluminum cylinder head or an expensive catalytic converter
destroyed by an inexpensive set of misfiring spark plugs.
course, some vehicles still require only a conventional spark plug
spark that must be replaced at 30,000- or 60,000-mile intervals. Beyond
those applications, the long-life spark plug should be sold exclusively
to prevent damaging expensive aluminum cylinder heads and catalytic
The sale can be made much easier if you ask your
customer to compare the cheapest spark plug in your inventory with the
most expensive. The customer will see at least three major differences.
First, the threads of the expensive spark plugs will be plated with
nickel or similar materials to prevent the spark plug from seizing in
aluminum cylinder heads.
Second, the center electrode will be very
pointed and perhaps needle-like in configuration to help the spark to
jump the air gap between the electrodes much more efficiently. Third,
the electrodes will be plated or contain precious metals like platinum,
palladium or iridium, which drastically reduces electrode wear. All of
these features combine to provide a steady, consistent spark that
reduces misfire emissions and lengthens catalytic converter life.
considering poor accessibility to the spark plugs on many modern
engines, it’s simply not cost-effective to spend three hours or more
replacing a set of long-life spark plugs with a set of conventional
spark plugs. The secret to selling long-life spark plugs is to help the
customer understand the benefits of long-life spark plugs and the
reasons the auto manufacturer requires long-life spark plugs in that
SPARK PLUG WIRES AND BOOTS
recommend replacing spark plug wires at specified intervals. For
example, the owner’s manuals of many late ‘90s Chrysler products
recommend replacing spark plugs and spark plug wires or cables at
60,000-mile intervals. Here again, this recommendation is driven by the
need to prevent damaging the catalytic converter by eliminating the
potential for ignition misfires.
While wire replacements aren’t
generally specified in most auto manufacturer’s scheduled maintenance
charts, real-world conditions dictate that wires should be replaced
along with the spark plugs at 100,000-mile intervals. In many cases,
the wire’s boots seize to the spark plugs and can easily break when the
wires are removed. Consequently, selling a set of wires to go with the
new spark plugs isn’t as much over-kill as it is good preventive
But the most fundamental reason for replacing wires
and spark plugs at the same time is to prevent flash-over spark leakage
from occurring. Because air gap voltage increases as the spark plug
wears, the high-voltage spark seeks the path of least resistance and
eventually begins to leak down the side of the external spark plug
insulator. This leakage causes a black carbon track to form on the
spark plug’s external insulator and, if we look inside the spark plug
boot, we’ll see a carbon track that matches the one on the spark plug.
If the wire or boot isn’t replaced, high secondary voltage will
continue traveling down the track or “flashover” in the boot, causing a
misfire that might damage the catalytic converter.
Most production resistor spark plug wires are made with a tough core impregnated with carbon particles.
type of core eliminates electronic emissions that interfere with radios
and sensitive electronic circuitry. The core is further coated with a
flexible silicone-based material that insulates the wire by containing
high secondary ignition voltages. The outer layer basically protects
the inner core from being damaged by atmospheric pollutants, oil and
abrasion. Wires are made in sizes that include the 6-millimeter wires
used on many Toyota products to the standard 7- and 8-millimeter
diameters used on many distributor and distributorless ignition
But, regardless of how well-made the original wire might
be, heat, oil, ozone, and high voltage will eventually increase the
fragility of the wire. Indeed, many old wires fail shortly after the
spark plugs are replaced simply because the very act of tugging them
off the spark plug has separated the wire internally or cracked the
wire or boot. OE wires should be replaced with wires of comparable
quality. Given the difficulties of access and current labor rates,
installing cut-rate spark plug wires isn’t always a cost-effective
repair. Because a secondary ignition failure illuminates the “check
engine” light on the instrument cluster on modern vehicles, the failed
wire can’t be covered up or concealed. It can only be replaced with a
quality ignition wire, as it should have been in the first place.
Goms is a former educator and shop owner who remains active in the
aftermarket service industry. Gary is an ASE-certified Master
Automobile Technician (CMAT) and has earned the L1 advanced engine
performance certification. He is also a graduate of Colorado State
University and belongs to the Automotive Service Association (ASA) and
the Society of Automotive Engineers (SAE).