What Are Coil Packs And Where Do They Go In The Engine?

A coil is exactly what it says, a coil of hair thin wire wraped thousands of times around a central core. It is sent electricity from your cars battery via your cars computer controller. The coil or coil pack amplifies this voltage many times over to usually 40,000volts or so and sends it on to the to the individual sparkplugs. Coil packs provide hi voltage to the sparkplugs in order to make the spark strong enough to jump across the electrode and ground gap on the business end of a sparkplug which is what ignites the air fuel mixture inside the individual cylinders and makes your engine "run". They are called coil packs because there is usually more than one coil terminal on them vs. A standard ignition system like my 5.9L V8 that relies on a distributor to direct individual sparks to each cylinder and has a single coil and a single terminal with which to do this . Some GM and Ford coil packs are centrally located on top of the engine or under the plastic dust cover on top of the engine, usually in sets of 2 on a 4cyl, 3 on a 6 cyl, and 4 on an 8cyl and usually with 2 terminals on each of the coil packs with wires that run from them to the sparkplugs. Find your sparkplugs and trace the plug wires back to the coil packs. Other newer Japanese, German cars have no plug wires at all and place the individual coils directly on top of the sparkplug boot( this is known as coil on plug), ie: A 4cyl engine would have 4 coils likewise a 6cyl would have 6 and an 8cyl would have 8. Hope this helps.

My 99 f-250 trk is idling rough, and very much loss of power mainly going up hill, and when I first take off. It has new air filter, new fuel filter.  Have been told that it could be coil pack.  Can you tell just by looking at coil pack to know if it is bad?  Does this sound typical for coil packs?  Thanks cjl

What does it usually cost to have a coil pack and 6 plugs installed?

In the old days a car had a single ignition coil. It lived on the firewall and a wire took the spark energy stored in it to the distributor where the spark energy was distributed to the spark plugs thru the spark plug wires as necessary.

Modern engines, due in part to much higher energy ignition requirements, need much more powerful ignition systems. In order to do this engines now have more then one ignition coil, sometimes known as "coil packs". In fact many engines have an ignition coil for each cylinder.

My dodge truck stalls out n sometimes if you steep on the gas it comes back and keeps running.Other times it just wont start again for about 10 mins I have changed the pulgs,wires and cap iam at a loss nand not sure what should be done next

Your coil  pack is located on lft or rt side on top of motor your spark plug wires r at the other end of it you may have one or two coil packs a bad coil pack will make your car shutter when idleing and shutter during take off

This is to broad in the fact that many different cars has different places the put them.

Most modern cars use one or more ignition coils for the ignition system. A coil pack is one casing with multiple coils in it. On this type of set up spark plug wires run from the coils or coil pack to the spark plugs. Even more recently you are seeing less and less of this design due to inherent inefficiencies. These cars use one coil per cylinder this is called Coil on Plug (COP) ignition. In this case the coil sits on top of the spark plug and is connected to it with a short boot acting as the spark plug wire. So if you have spark plug wires follow those to coil(s) if not the coil is bolted on above the spark plugs.

Coil packs are what make the spark for your plugs  they are on the top side of the motor most of the time