Skip the auto shop - Our mechanics make house calls

How Does a Distributor Work?


In older cars, a distributor is one of the central parts of the ignition system. Since the early 1990's, many automakers have moved to using ignition systems without distributors. Though the number of cars with distributors has declined over the years, there are still quite a few on the road.

What is a distributor?

The distributor is responsible for getting the electrical charges needed for combustion within the engine out to each of the cylinders. The coil (outside the distributor) creates the very strong electrical charge needed for this process. Inside the distributor, a rotor spins in time with the car’s camshaft, transferring that charge to designated contacts (one per cylinder). As the rotor spins, it passes very close to each contact and the charge jumps from the rotor to the contacts, and then into the wires and plugs.

If you have an older vehicle, your distributor also has breaker points built into it. The purpose of these points is to ground the incoming current and facilitate the pulses of electricity getting to the proper cylinders. A cam from the distributor connects with each point in turn, breaking the ground on the coil, which opens the path for the electric charge to come through.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How Long Does a Throttle Return Spring Last?
Not all vehicles on the road feature an electronic throttle control (ETC), which is also called drive-by-wire. For vehicles that don't offer this system, they have a throttle cable instead that...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...

Related questions

Q: 86 GMC 305 quits firing occasionally

This car is very old. Personally, I'd just go and get a rebuilt distributor. Most companies sell the rebuilt distributors with the lifetime warranty. They don't cost that much. Replace your entire distributor assembly. If that doesn't fix it,...

Q: Electrical turning off.

The symptoms you describe are most commonly caused by the ignition switch loosing contact to one or more contacts in the switch. I would try and wiggle the ignition key to see if the problem comes and goes. This would...

Q: Service light change plugs

Hi there. Spark plugs are not generally sensitive to time. Being that they are 4 years old does not constitute that they need to be replaced. I would replace them at 40,000 miles only unless you have a warranty on...