Thankfully today’s cars no longer have distributors. Modern engines use separate coil packs, which are less complex. But there are still countless vehicles on the road that have a distributor hidden under the hood. And sometimes those distributors need replacement.
What is a Distributor in a Car?
Before getting into distributor replacement, let’s talk about what a distributor is. You’ve probably never heard of a distributor before, especially if you’re a young millennial or a member of Generation Z.
A distributor is an ignition element that, as its name suggests, distributes the spark to each of the engine’s spark plugs. Voltage is sent from the ignition coil through the spark plug cord to the distributor cap. That voltage then travels from the center terminal of the cap to the rotor located inside the distributor.
As the distributor turns, the rotor turns precisely, distributing the voltage one by one to the outer terminals of the cap. The voltage then travels from each outer terminal of the distributor, through a separate spark plug wire, to each spark plug. The spark plug then ignites the air/fuel mixture inside the engine.
In most cases, automobile distributors include a triggering mechanism (usually a pickup coil) that monitors the rotation of the distributor. The mechanism sends a signal to the Engine Manipulation Module or the Ignition Management Module. In some cases, the ignition module may also be located inside the distributor.
The module uses information from the triggering mechanism along with data from other engine sensors to determine when to fire the spark plugs. To accomplish the task, the module interrupts the ignition coil number one winding in modern times, increasing enough over-voltage across the secondary winding of the coil to ignite the spark plug. In this way, the car’s electronics can control the ignition timing, exactly when the spark is brought to each cylinder of the engine.
Most distributors have a device at the bottom. That tool matches the tool on the camshaft. The distributor is offset from the camshaft so that the ignition timing and engine timing are in sync. In older motors, the distributor may be rotated to control the base ignition timing.
However, on more recent motors, the base timing is often fixed. Additionally, in many cases, the distributor serves the secondary purpose of driving the engine oil pump.
Bad Distributor Symptoms
A faulty distributor can cause many problems. Here are some of the most common symptoms:
Engine Performance Problems
A faulty distributor can cause a wide range of engine performance problems, such as stalling, misfiring, and poor acceleration.
check engine light
If your vehicle is made within the last few decades, chances are that a problem with the distributor will trigger the check engine light.
engine cranks but does not start
If the distributor is bad, the engine will not get the spark it needs. As a result, the engine will crank, but it will not start or turn.
increase in emissions
A bad distributor can cause engine failure. This could lead to an increase in emissions and, potentially, a failed state emissions test.
unusual sound
In some cases, wearing distributor bushings or bearings allows the distributor to move around and produce unusual noises.
How to Replace a Distributor
Now we come to the fun part: distributor replacement. Are you ready to grab some tools and get dirty? good, We are going to discuss replacing the common electronically controlled, non-adjustable distributor.
Note: The following outline covers the option when the crankshaft is no longer rotated. If the connection between the engine and the distributor goes bad, let’s say because the engine has been replaced, you will need to give the distributor time for the engine. Before you start, keep in mind that all motors are different.
Be sure to follow the restore record on your specific application. Restore guides are useful, including Chilton, although all data subscriptions are better. AllData has single-automobile subscriptions for Dyer that provide exclusive manufacturing facility repair records.
Note: The following general guidelines are for educational and entertainment purposes only. Consult your vehicle’s factory information for specific repair instructions and recommended safety procedures.
Depending on the type of car you have, the tools needed to replace the distributor may vary. But in general, you will need:
- Ratchet and appropriate size sockets and wrenches
- Safety glasses
- Screwdriver (some vehicles)
- Torque wrench
How to Remove the Distributor
- Put on your safety glasses.
- Disconnect the negative battery cable.
- If you are replacing the distributor cap, remove the spark plug wires. On the other hand, if you are reusing the cap, you can remove it from the distributor (connected to the plug wire) and put it aside.
Note: All vehicles have a specific firing order. The plug wire should go to the appropriate terminal on the distributor cap. Otherwise, the firing order will be incorrect and the engine will either run poorly or not run at all.
In some cases, the distributor cap and plug wires are numbered so they don’t get mixed up. But if you don’t have numbers, you’ll want to make sure to mark them to prevent them from getting mixed up.
You can use a piece of tape and a pen to tag each plug wire.
- Disconnect all electrical connectors from the distributor.
- Mark the position of the distributor base with respect to the engine. You can use a permanent marker or whiteout to do this. The position must be marked to ensure that the new distributor is correctly aligned during installation.
- Mark the position of the rotor with respect to the distributor housing (which side the tip points to). The position must be marked to ensure that the new distributor is correctly aligned during installation.
- Remove the distributor hold-down bolt and clamp.
- Remove the distributor by pulling it up and out of the engine. As the distributor is removed, the rotor will turn slightly. Note the position of the rotor tip when it stops turning and also marks that position with respect to the distributor housing.
- Make sure the old distributor O-ring is removed from the engine.
CAUTION: Do not turn the engine crankshaft after removing the distributor.
How to Install a Distributor
- Compare the new distributor with the old one to make sure both are the same design.
- Mark the new distributor at the exact same location you marked on the original unit during steps 5, 6, and 8 of the distributor removal process. To do this, you must remove the limit from the new distributor.
- Rotate the distributor by hand so that the rotor points to the same position as created in step 8.
- Carefully install the distributor (with the new O-ring) into the engine. If everything was done correctly up to this point, the rotor should turn, then line up with the markings made in Step 5 and Step 6.
Note: You may need to play with the distributor so that its gear teeth match the camshaft.
- Reinstall the distributor cap.
- Install the distributor hold-down clamp. Use a torque wrench to tighten the retaining bolt according to the manufacturer’s specifications.
- Reinstall the electrical connectors leading to the distributor.
- Reinstall spark plug wires according to the engine firing order.
- Reconnect the negative battery cable.
- Start the engine. If the vehicle runs poorly or the check engine light is on, the distributor was installed incorrectly. You will have to remove the distributor and reinstall it.
Additionally, you may need to set the engine timing for the distributor, as described below.
As mentioned, if the engine is exhausted anyway, you will need to do a few extra steps before putting in the distributor. Marks made while closing the distributor will no longer be valid and you will have to give the new distributor time to the engine.
Typically, the technique involves bringing cylinder No. 1 to the top dead center (TDC) on the compression stroke, then positioning the distributor so that the rotor points toward (or near) the No. 1 cylinder terminal on the distributor cap. Consult the manufacturer’s restoration records for the exact method.
Car Distributor Replacement Cost
If you’re going to hire a specialist to replace your distributor, this is a neat trick. If you’re unsure of your mechanical strength, expect to pay anywhere from around $300 to $1,000. The activity can be even more spectacular when you own a high-end luxury or performance car.
Should you decide to tackle this activity yourself, expect to pay around $100 to $300 for a new or manufacturer distributor. Still, if you are given an extended car, the fee may be better.
FAQs.
How does an ignition distributor work?
As the engine spins, the distributor shaft cam turns until a high point on the cam suddenly separates the breaker point. Immediately, when the points are opened (separated) the current flow through the primary windings of the ignition coil stops. Due to this, the magnetic field around the coil is broken.
What are the parts inside a distributor?
The distributor consists of the following parts:
- Cam
- Capacitor.
- condenser.
- contact breaker.
- distributor cover.
- terminal.
- distributor shaft.
- drive gear.
How do you diagnose a distributor problem?
- Check the distributor cap. Often the distributor cap is questionable.
- Check the contact points. Inspect the condenser; If the engine is damaged it will not work.
- Check the arc.
- Tools and materials.
- Crank the engine.
- Remove the old distributor.
- Set the point gap.
- Set up a distributor.
What would cause a distributor to not turn?
It is possible that the camshaft gear has come off the camshaft and the distributor shaft has not turned. Remove the timing cover and turn the crankshaft and watch the timing chain move the camshaft. If the distributor does not turn but the camshaft does, take the distributor out and look at the gears.
What module controls the ignition timing?
Powertrain Control Module (PCM): The brain of the car. The PCM controls ignition timing, fuel delivery, valve timing in engines with variable valve timing), emission functions, turbo boost pressure in turbocharged engines, idle speed, throttle position, and cruise control.
What are the parts of the ignition system?
The basic components in an ignition system are a storage battery, an induction coil, a device for producing a timely high-voltage discharge from the induction coil, a distributor, and a set of spark plugs.
How can you tell if a distributor rotor is bad?
Common signs include an engine misfire, the car not starting, the engine light coming on, and excessive or unusual engine noise.
Can a car start without a distributor?
If the distributor is bad, the engine will not get the spark it needs. As a result, the engine will crank, but it will not start or turn.
