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No Spark From Distributor To Plugs (How To Test + Potential Causes)

March 22, 2022

No spark from distributor to plugs can be frustrating, thanks mainly to the myriad of potential causes. 

If this describes your current situation, you may be wondering — 
What’s the best way to test if the distributor is the problem? 
And if it isn’t the distributor, what else could it be? 

In this article, we’ll answer those questions and take a look at a few distributor-related FAQs

This Article Contains: 

Let’s get started! 

No Spark From Distributor To Plugs: How To Test

A range of factors can cause starting issues. As such, it’s essential to begin by determining whether the distributor is causing the problem. 

Note that the distributor is quite a complex piece of equipment that’s difficult to access. If you’re not comfortable disconnecting various components to access the distributor, let a professional mechanic handle it instead. 

Before you begin the test, ensure your car battery is fully charged, and you have another pair of hands nearby. Then: 

If there’s no spark or a weak spark, the next step is determining the reason.

No Spark From Distributor to Plugs: 6 Potential Causes

If your engine cranks but won’t start, there’s a good chance it’s because it’s failing to produce a good spark or simply won’t spark. However, any number of reasons could be causing the issue.

Here are six of the most common:

1. Dirty Or Corroded Distributor Cap

The distributor cap is a good starting point. 

Open the cap and ensure the inside and outside are clean. There should be no erosion on the surface, and the firing points should be free from rust and decay

While you’re there, check the rotor, rotor arm, and rotor button are in good working order. A faulty distributor rotor can short the coil voltage, resulting in a faulty connection in the cap’s terminal — which can then lead to a misfire in the spark plugs. Ensure each rotor point is clean. 

Alternatively, the distributor condenser could be the issue. 

2. A Bad Crankshaft Position Sensor

The crankshaft position sensor monitors the position and rotational speeds of the crankshaft. 

Without the crank sensor, the engine control module (ECM) wouldn’t know when to fire the fuel injectors and ignite the spark plugs

When the crank sensor begins acting up, it can’t supply the ECM with the correct information. ASs such, a bad crank position sensor often manifests as a failure to start, but more worryingly, it can cause the engine to stall at any speed. 

Begin by looking for a corroded, loose, broken wire from the powertrain control module. Fuel won’t make it to the injectors if the crank position sensor doesn’t signal the ECM. 

3. An Issue With The Ignition Control Module

The ignition control module manages the flow of electrical current fed to the ignition coil, which generates the coil voltage necessary to fire the spark plugs.

If your ignition control module is on the fritz, you’ll find your car occasionally stalling. If the ignition control module has failed altogether, it’ll create a weak spark, and the car won’t start

Check to see if the switch and terminals are free from rust and replace any damaged or broken spark plugs wires as necessary.

Alternatively, it could be a bad ignition module. 

A simple way of testing the ignition module is to leave the car idling for 30 minutes and then tap the ignition module with a screwdriver. If the car stalls, it’s a strong suggestion that your ignition module is acting up. 

4. Issues With The Pickup Coil Inside The Distributor

The electronic ignition pickup coil sits inside the distributor and triggers the ignition system to produce a spark. As such, if there’s an issue with the pickup, it can make starting your car difficult. 

The signal may cut out intermittently in an old or failing pickup, causing the engine to stall. Depending on how worn the pickup coil is, you may be able to start the vehicle again. 

While you’re checking the distributor, ensure the ballast resistor is working as it should. The ballast resistor stabilizes electrical current that flows to the ignition system, helping prevent additional wear. 

5. A Bad Ignition Coil

The ignition coil generates and sends a high voltage pulse to the spark plugs. 

One of the telltale signs of a faulty ignition coil is the engine dying suddenly after running for several minutes. This often happens because the coil is too hot, either because you have a bad ignition coil or another component is defective, and the coil is receiving too much current. 

When checking for a faulty ignition coil, look for any signs of cracks, burns, melting, or leakage from older canister coils. If any of these are present, the coils need replacement. 

Additionally, double-check each spark plug wire, looking for a loose connection at the spark plug cap. The spark plug cap ensures no voltage leaks, but heat and abrasion damage can cause a broken wire, leading to many issues.

An easy way to check your spark plugs wires is with a spark tester or a digital multimeter set to ohms. Ensuring the proper working order of each spark plug wire can save you the headache of dealing with a larger ignition problem.

6. A Faulty Ignition Switch

Of course, all your vehicle’s components may be working fine, and the problem stems from the ignition switch itself. 

An excellent way to tell if your ignition switch is acting up is when you turn the key to activate the car’s accessories; the dashboard lights won’t illuminate. 

3 Distributor FAQs

Let’s take a look at some common distributor-based questions and their answers: 

1. What Is A Distributor?

In older vehicle models, the distributor is an integral part of the ignition system. As its name suggests, it distributes sparks to each spark plug

Voltage travels from the ignition coil to the distributor cap via the coil wire. From there, the voltage travels to the distributor rotor. 

The distributor shaft and the rotor begin rotating, distributing voltage to each cap’s outer terminals. 

Then, the voltage travels from the distributor’s outer terminals, through the various spark plug wires, to each spark plug. This causes the spark plug to fire, igniting the air/fuel mixture in the combustion chamber. 

Newer cars without distributor ignition systems have replaced the single ignition coil with a coil pack that sits directly above each spark plug.

2. How Much Does A Distributor Replacement Cost?

Considering the complex nature of the distributor and its hard-to-reach position, it may be easier to let a professional handle it. 

In this case, you can expect to pay between $89 and $123. This price includes the parts, which should cost between $39 and $59, and the labor, usually costing between $50 and $64. 

Of course, if your vehicle has a complex setup, labor costs will increase, especially if other components need replacing as well. 

3. What’s A More Convenient Solution For Replacing The Distributor?

If you’re comfortable with engines, replacing the distributor shaft assembly yourself shouldn’t be too much of a hassle. However, if you don’t have the experience and the correct equipment, it’s best to leave it to the professionals. 

If you’re looking for a reliable mechanic to perform auto repairs, look no further than RepairSmith

RepairSmith is an all-in-one mobile auto repair and maintenance solution offering competitive and upfront prices, a 12-month, 12,000-mile warranty, easy and convenient online bookings, and more.

Wrapping Up

Unfortunately, diagnosing an ignition problem like why your car has no spark or refuses to produce a good spark can be time-consuming and frustrating. 

If you’re not comfortable with engines, it might be best to let our ASE-qualified professionals at RepairSmith handle the troubleshooting.