Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. Symptoms of a Bad or Failing Distributor Rotor and Cap

Symptoms of a Bad or Failing Distributor Rotor and Cap

distributor rotor and cap

A running engine sends a large amount of electricity through the ignition coils to the rotor, which turns inside the distributor. The rotor routes the energy in a specific through the spark plug wires ultimately to the engine’s cylinders in the correct firing order.

The distributor rotor and cap keep the distributor’s contents separate from the engine and keep the distributor’s working parts clean and tidy – while supporting the incredibly high volts of energy and delivering them to the appropriate spark plugs. The spark plugs utilize the spark from the distributor to ignite the fuel mixture, which is what keeps the engine running.

High voltage runs through this entire distributor system during the operation of your vehicle, but if there's an issue this voltage won’t get distributed to the correct spark plugs to ensure that your engine will run. Usually a faulty distributor rotor and cap will produce a few symptoms that alert the driver that service may be required.

1. Engine misfires

Engine misfires can occur for a number of reasons. Checking your distributor rotor and cap to see if they need to be replaced is one way to ensure that everything is in solid working order.

2. Car doesn’t start

When the distributor cap isn’t on tightly or is malfunctioning, the engine is unable to send the spark through the entire circuit required to move the cylinders – which ultimately make the car run.

3. Check Engine Light comes on

Your Check Engine light can mean a number of different things, but when you see this light on along with some of the other symptoms listed here, it’s time to call a professional to see what the code is from your car’s computer.

4. Excessive or unusual engine noises

Your vehicle may make some very strange noises if the distributor rotor and cap are malfunctioning – specifically because the cylinders will try to fire but fail. You might hear a tapping, clicking, or sputtering sound when the distributor rotor and cap are failing.

Any time you have routine service performed on your vehicle, ask that the ignition system be checked for defects or problems. If you experience any trouble starting your car get assistance from a qualified mobile automotive technician from YourMechanic.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on

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

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.


More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....

Related questions

Q: Engine not sparking; van cranks but won't turn over

If you are sure the fuel system is working correctly via pressure and injector firing, then the ignition would be logical to look at. Whether you have a 6-cylinder or 8-cylinder engine the ignition system is similar. The ignition has...

Q: I purchased performance brake pads and rotors however I only have a front pair of rotors.. 2014 Ford Mustang

Hi there - while there may be a very slight performance gain to be had by also replacing the rear rotors, you will be fine without doing so unless the rear brake rotors are severely grooved or otherwise worn. The...

Q: several warning lights on

Hello there, it is unusual for all of these lights to come on at one time with your 2004 Toyota Sienna. The most common cause of a malfunction that effects all these systems is an electrical one such as a...