What Causes HEI module failure?


Most common cause of module failure is still overheating of the in cap coil, and its layer shorting, causing increased resistance the coil trigger side of the module cannot handle.

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Subsequently, one may also ask, how do I know if my HEI module is bad?

Signs & Symptoms of a Bad Magnet Pick Up HEI Distributor

  1. Engine Fails to Start. If the positive hot wire from the battery that feeds the distributor has no voltage to it, the HEI distributor will not function.
  2. Plug Wire Engine Miss.
  3. Reduced Fuel Economy.
  4. Weak Spark.
  5. Electrical Arc and Shorts.
  6. Hard Starting.
  7. Smog Check Failure.

Furthermore, what happens when ignition module goes bad? Engine performance issues One of the first symptoms of a problem with the ignition module are engine performance issues. If the ignition module fails or has any problems it can lead to performance issues with the vehicle, such as misfires, hesitation, loss of power, and even reduced fuel economy.

Thereof, what causes ignition module failure?

The number one reason that ignition modules go bad is because of heat. On most of the cars that have a recurring problem with this, they have the original distributor in the car. As the distributor ages and wears, the bushing in the shaft goes goes bad and starts to cause excessive heat.

Can bad spark plugs cause stuttering?

Common Symptoms of Bad Spark Plugs. Slow acceleration will quickly follow poor fuel efficiency. As the symptoms of bad spark plugs get more serious, the car’s engine will start to misfire. Engine misfires will create stuttering sounds and emit more exhaust fumes than normal.

How do I find my HEI module?

Easy tests for HEI system:
  1. Test for power at the pink BAT terminal. You should have battery voltage w/ the key in the start and RUN positions.
  2. Connect the ground side of your test lamp to the battery POSITIVE cable.
  3. Remove the cap & rotor.
  4. DVOM (meter) still connected to green & white leads.

How do you test an ignition control module with a multimeter?

Check for voltage at the coil positive terminal when the ignition key is on. Place the red lead of the multimeter on the positive coil terminal. Place the black lead to the battery negative terminal. Turn on the ignition switch to the “Run” position.

How do you check the ignition module on a HEI distributor?

Turn the ignition ON. Touch the probe of the test light to the smaller terminal of the module–it’s labeled “G” and had the Green pickup coil wire connected to it. When you pull the probe OFF the terminal, you should hear a snap (the spark) from the coil.

What is a HEI module?

High energy ignition. HEI is characterized by the incorporation of the ignition coil into the distributor cap for most applications. The system consists of a control module and a magnetic pickup mounted in the distributor. This eliminates ignition points and the coil wire.

How do you check a distributor pickup coil?

These are the test steps:
  1. Disconnect the pick up coil connector at the ignition control module.
  2. Connect BLACK test lead of the multimeter to one of the female terminals of the connector (using an appropriate test lead).
  3. Connect RED test lead of multimeter to the other female terminal of the pick up coil connector.

Can a bad distributor cause loss of power?

Misfiring can be caused by loss of spark; imbalanced air/fuel mixture; or loss of compression. This includes worn, fouled or damaged spark plugs, bad plug wires or a cracked distributor cap. Sometimes, misfiring may not be caused by a total loss of spark but by incorrect sparking or by high-voltage electrical leaks.

How do you fix an ignition control module?

How to Replace an Ignition Control Module
  1. Park your vehicle in a safe place and locate the ignition module.
  2. Look under the dashboard.
  3. Open the hood and remove the distributor cap using a Phillips screwdriver or ratchet and socket, but do not disconnect the spark plug wires from the distributor cap.
  4. Look on one side of the distributor.

How much does it cost to replace an ignition control module?

The average cost for an ignition control module replacement is between $274 and $386. Labor costs are estimated between $65 and $83 while parts are priced between $209 and $303. Estimate does not include taxes and fees.

Where is ignition control module located?

The Ignition Control Module (ICM) is located in the distributor housing near the ignition coil. To access the module, remove the distributor cap, rotor, and if equipped, the dust cover.

Does the ignition control module control fuel?

The ignition module of your vehicle is the heart of your entire ignition system. Its two main roles are to create a spark strong enough to ignite the air/fuel mixture for combustion and to control the timing of the spark plugs by opening and closing the ignition coil ground circuit.

How do you diagnose a bad ECM?

Engine Stalling or Misfiring

Erratic engine behavior is another common symptom of a bad or failing ECM. A faulty computer can also be responsible for engine stalling or misfiring, though this tends to be more intermittent. These symptoms may come and go, and may appear to have no pattern to their severity or frequency.

What does a Ignition Control Module do?

It controls th ignition coil’s firing time. The ignition control module is the heart of an automobile’s ignition system. It regulates spark generation within the engine. The ignition control module relies on the car battery to provide the ‘spark’ that sets the ignition system in motion.

How do you test an ignition control module in GM?

If your GM vehicle has a slow or hard start, the ignition control module should be tested with an electrical test light.
  1. Open the hood of the GM vehicle. Locate the ignition module.
  2. Connect the positive test light lead to the ignition module signal wire.
  3. Ask a partner to crank the engine numerous times.

Why is dielectric grease used on the ignition module?

Dielectric grease is pretty much all silicone and use to keep moisture out not as a heat sink. Something else you might want to do, put a couple of washers per side between the ICM bracket and head.

How many volts does a stock HEI put?

Point ignitions two power systems that are controlled by ignition switch position 12 volts for starting and 9 volts running. The HEI just uses 12 volts. If it’s wired like points it will work on 9 volts but has problems being consistent especially at higher RPMs.

Are HEI distributors good?

An HEI distributor is a great piece of equipment for an over-the-road car because it is completely self-contained. But without an external coil, a stock HEI cannot provide a strong spark at rpm levels commonly seen on the racetrack. Engines with higher compression or more horsepower also require a hotter spark.

What is ignition control unit?

The Ignition Control Module is a part of the ignition system. It manages the electrical current that is fed to the ignition coil in order for it to generate the right amount of voltage for the spark-plug to ignite the fuel mixture. In turn, the ignition control module sends the input to the ignition coil to fire it up.