The ignition module in an HEI is also easily upgradeable for horsepower gains. Think of it as the ignition's brain. It controls the current sent to the coil, which, if fed a higher current, can feed the spark plugs at increasingly higher rpm.
How do I test my Hei module?
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.
How to tell if an ignition control module is bad?
Symptoms of a Bad or Failing Engine Control Module (ECM)
- Check Engine Light Turns On. An illuminated Check Engine Light is one possible symptom of a problem with the ECM. ...
- Engine Stalling or Misfiring. Erratic engine behavior may also indicate a bad or failing ECM. ...
- Engine Performance Issues. Engine performance issues are another symptom of a possible problem with the ECM. ...
- Car Not Starting. ...
- Poor Fuel Economy. ...
Is there a way to test a Hei module?
for the HEI gurus, does this look like a good way to diagnose HEI issues? "The easiest way to test a module on the car is to ensure that the wiring & pickup coil are OK. The module is essentially an amplifier with a built in analog to digital convertor. Easy tests for HEI system:
How to test for bad ignition control module?
Symptoms of a bad ignition control module
- Check Engine Light. The Check Engine light illuminates any time the vehicle detects a problem with a component that’s related to the functioning of the engine.
- Engine misfires or runs rough. The ignition control module controls the strength of the ignition spark as well as its timing. ...
- Module overheating. ...
- Vehicle stalls suddenly. ...
- Acceleration issues. ...
How do I know if my HEI ignition module is bad?
a faulty ignition module can affect ignition timing, resulting in an engine that misfires and runs rough. the engine may also run well at low speed, but won't accelerate well. 3. stalling: a failing ignition module can occasionally prevent the engine from getting spark, causing it to stall.
What does HEI ignition stand for?
High energy ignitionHigh energy ignition, also known as H.E.I., is an electronic ignition system designed by the Delco-Remy Division of General Motors.
What are the benefits of an HEI distributor?
The HEI system produces a more powerful spark, which allows for a wider spark plug gap. This delivers better ignition of the fuel/air mixture. The HEI setup was so popular, it became a must-do swap into non-GM vehicles as well.
How do you test a Chevy HEI ignition module?
3:024:44HEI distributor testing free easy way - YouTubeYouTubeStart of suggested clipEnd of suggested clipIt's going to blink or the slower you spin it the slower. It's going to blink. So i'm going to tellMoreIt's going to blink or the slower you spin it the slower. It's going to blink. So i'm going to tell you right now. This ignition module pickup coil. And everything has potential work just.
What is an HEI module?
An HEI distributor is still an inductive-discharge ignition, but it exchanges the points for a solid-state electronic switching device called a module. Since this system produces more voltage and amperage output, it demanded a larger-diameter cap to prevent voltage crossfire inside the distributor cap.
How do you tell if my distributor is HEI?
0:372:42Difference Between HEI & Non-HEI Spark Plug Ends - YouTubeYouTubeStart of suggested clipEnd of suggested clipCompanies build a hold down that'll keep all the boots and terminals held on to the distributor capMoreCompanies build a hold down that'll keep all the boots and terminals held on to the distributor cap but this is what an hei end looks like.
Can you run without vacuum advance?
You need the vacuum advance for best performance at low throttle settings for the street as Barry said. If you were running on a circle track or a drag strip there wouldn't be a need for it because the mechanical advance would be doing the job.
What years did Chevy use HEI distributor?
GM's High energy ignition (HEI), designed and built by the Delco-Remy division of General Motors starting in 1974. These units were used on all engines in 1975 through the mid-1980s, with several different variations over the years.
How do you adjust the mechanical advance on a HEI?
1:212:53How to increase HEI distributor mechanical advance - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo please on what you want to do is grind where I have these white marks on this Center metal barMoreSo please on what you want to do is grind where I have these white marks on this Center metal bar you grind there where it contacts these outer pieces that will let it.
Why is my HEI distributor not firing?
If the battery voltage drops below 10.5 volts while cranking, you probably have a bad battery. This low voltage could be insufficient to get the distributor to fire. Use a volt meter to test the hot wire while a buddy cranks the engine over. If the voltage drops below 10.5, check your battery.
Why is my distributor not getting spark?
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.
How do you troubleshoot a HEI distributor?
0:0010:13How to Diagnose HEI Distributer, No Spark No Start. - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo before you start pulling apart your distributor you want to check and make sure that you'reMoreSo before you start pulling apart your distributor you want to check and make sure that you're receiving power to your distributor.
What years did Chevy use HEI distributor?
GM's High energy ignition (HEI), designed and built by the Delco-Remy division of General Motors starting in 1974. These units were used on all engines in 1975 through the mid-1980s, with several different variations over the years.
When did GM switch to HEI distributors?
1975Chevrolet's High Energy Ignition (HEI) from the Delco-Remy Division of General Motors was first offered in 1974 on production cars, though in very limited numbers. In 1975, HEI became standard on all GM vehicles.
How do you adjust the HEI ignition timing?
4:067:31HEI Ignition Tips for Your Engine - YouTubeYouTubeStart of suggested clipEnd of suggested clipYou can adjust timing by loosening the nut on the distributor clamp. And rotating the distributor aMoreYou can adjust timing by loosening the nut on the distributor clamp. And rotating the distributor a couple of degrees.
How does HEI vacuum advance work?
3:336:18How Ignition Timing Works: Vacuum and Mechanical Advance Explained!YouTubeStart of suggested clipEnd of suggested clipThe vacuum created by the engine pulls on the diaphragm. Found inside the vacuum canister. As theMoreThe vacuum created by the engine pulls on the diaphragm. Found inside the vacuum canister. As the diaphragm. Moves it rotates a plate which advances or retards the ignition timing.
What is HEI distributor?
The HEI distributor is still an inductive-discharge ignition, but exchanges points for an electronic device called a module. Since this system produces more voltage and amperage output than a point-type ignition, it requires a larger-diameter cap to prevent voltage crossfire inside the distributor cap.
Why are Hei coils cooler?
HEI Coils also run cooler because they are encapsulated in thermal epoxy, which dissipates heat more efficiently than oil-filled coils. The solid epoxy, in comparison to oil-filled coils also eliminates the possibility of leaks.
What speed does a Hei distributor give up?
Early HEIs were infamous for giving up at speeds above 5,000 rpm-so many avoided them. This was true of the early-model distributors, but it didn't take GM long to modify the modules and coils to offer greatly increased spark energy at higher engine speeds. These days there's a plethora of aftermarket high-performance modules, coils, and complete ready-to-run HEI distributors that can be added to a high-performance engine that'll provide excellent spark energy and rpm potential well in excess of 7,000 rpm.
Does vacuum advance increase horsepower?
Vacuum advance doesn't lead to more horsepower. Vacuum advance immediately begins to decrease as soon as you accelerate, and at wide-open throttle vacuum disappears. However, it is recommended that you connect your vacuum advance hose to direct manifold vacuum because it will provide you with more vacuum advance at idle, which will help to keep your plugs cleaner. Some motors will idle too fast/rough at manifold vacuum, in which case you will need to connect your vacuum advance to ported vacuum.
Is a HEI rotor phased?
Myth 9: An HEI rotor must be phased. On an HEI, if you use the holes in the housing that were originally there for the vacuum advance, to install your vacuum advance eliminator, there is no cause for rotor phasing. It will already be phased correctly due to the original design. Myth 10: Not necessarily a myth but a fact.
How does a HEI module affect horsepower?
Increased horsepower and torque are a direct result of higher cylinder pressures. However, these higher pressures require more spark voltage and current in order to ensure complete combustion. The beauty of an HEI is that even stock, it applies much more spark energy than a points-type ignition. Generally, stock HEI modules are current-limited to about 4 amps. Better GM performance modules increase this current to around 5.5 amps. Some of the more high-performance aftermarket modules can draw as much as 7.5 to 8 amps of power. The problem with higher amperage is heat. The heat can eventually build up inside the distributor, melt the internal circuits, and destroy the module. This is especially true at idle since the energy remains in the module (since little is needed at idle), which adds to the heat problem.
What is a Hei distributor?
An HEI distributor is still an inductive-discharge ignition, but it exchanges the points for a solid-state electronic switching device called a module. Since this system produces more voltage and amperage output, it demanded a larger-diameter cap to prevent voltage crossfire inside the distributor cap. This larger cap also offered space to position the coil, making the HEI distributor self-contained. All you have to do to run this system is to apply a straight 12 volts to the distributor and you’re ready to run.
How much rpm does a GM distributor give?
Today, there are several aftermarket high- performance modules and coils that can be added to a stock GM HEI distributor to give it excellent spark energy and rpm potential up to 7,000 rpm.
What does more power mean on a coil?
More power applied across the primary circuit of the coil means the coil can apply greater spark energy to the spark plugs. This additional power ensures more complete combustion at both idle and at wide open throttle. Increased horsepower and torque are a direct result of higher cylinder pressures.
How to reduce heat buildup in a module?
The key to reducing heat buildup in the module is to use the special white grease supplied with new modules on the mounting side of the module. This grease creates a better heat transfer path between the module and the distributor body so that the module tends to run cooler. According to ACCEL, you should not use the clear dielectric grease on these modules (like MSD’s Spark Guard) since this is actually an insulator type of grease that will act as a heat transfer barrier, which could lead to trouble.
What happens when a distributor is idle?
The heat can eventually build up inside the distributor, melt the internal circuits, and destroy the module. This is especially true at idle since the energy remains in the module (since little is needed at idle), which adds to the heat problem.
Does an ignition system make horsepower?
Ignition systems don’t make horsepower, but a weak ignition can cost you power if it can’t get the combustion process started. There are plenty of killer ignition systems that could probably weld sheetmetal, but those monster capacitive-discharge (CD) systems aren’t necessary for a typical street engine.
What is a HEI distributor?
GM’s high energy ignition (HEI) distributor has been used as an affordable, easy to install performance distributor since its introduction in the mid 70s. It should come as no surprise being one of the most popular options among modern rodders and race enthusiasts to this day. Most of the original GM V-6 and V-8 models used an ignition coil inside the distributor cap, making it a one-piece ready-to-run distributor. HEI ignition systems are very dependable and offer great performance on a number of applications. The heart of any ignition system is the coil, battery voltage is supplied on the positive side, while the negative side is repeatedly pulsed to ground. When the negative lead is grounded, the primary (low-voltage) circuit is completed and a magnetic field is generated by the coil windings. When the circuit is opened, the magnetic field collapses and induces a high-voltage spark from the secondary winding to the spark plug.
What color are the coil leads on a Hei?
Factory HEI. On a factory HEI, the primary coil leads will either be white and red, or yellow and red. The colors of the leads determine the direction the coil is wound, which determines its polarity.
What is the heart of an ignition system?
The heart of any ignition system is the coil, battery voltage is supplied on the positive side, while the negative side is repeatedly pulsed to ground. When the negative lead is grounded, the primary (low-voltage) circuit is completed and a magnetic field is generated by the coil windings.
What is the part number for vacuum advance?
-If you are not using a vacuum advance, we recommend using our lock plate, part number 91012339. This will keep the timing steady without any flutter that the vacuum advance can cause.
Why does my ignition control module go bad?
Over time of use, the ignition control module can go bad due to plenty of reasons. Whatever the reason is, as a driver, you must take care of the problem and replace the faulty components in the ICM immediately ...
How much does it cost to replace an ignition control module?
Luckily, replacing the ignition control module is not a big deal and is not one of those expensive repairs. It usually costs between $50 in $250, which is not too bad. However, you have to be careful about where you're getting the job done because labor costs can be a major component.
What is the main module responsible for monitoring and maintaining the spark?
To prevent dealing with such situations, it is important for you as a driver to keep an eye and ear for any symptoms of a bad ignition control module which is the main module responsible for monitoring and maintaining the spark.
What is an ICM?
To put it simply, the ignition control module or the ICM is a simple switch in the vehicle responsible for turning the ignition system on and off.
What to do if you see a check engine light?
That's why it's recommended that once you see a check engine light illuminating is to take your vehicle to the nearest repair shop and have a mechanic confirm the main culprit. If you have an OBD 2 scanner, you can simply plug it into your vehicle and scan any errors to give you hints about what's the real culprit.
Why does my check engine light illuminate?
Since the check engine light illuminates for various reasons, it can be hard to tell whether it's coming from a bad ignition control module. That's why it's recommended that once you see a check engine ...
Why replace ICM?
Whatever the reason is, as a driver, you must take care of the problem and replace the faulty components in the ICM immediately to prevent major damages to your engine and also prevent burning your life at risk of accidents, especially when the engine doesn't provide the required energy at the right time.
What is the ground strap on a distributor?
the ground strap I referred to is internal to the distributor. It's a piece of stamped steel with some kind of gray coating on it. If the battery ground cable is attached to the engine as it should be the engine is grounded as well as it'll ever be. Those straps are for grounding the body to the engine, not the other way around. Where does the battery ground cable attach to the engine?#N#When you check the pickup coil note what color the the wires are.
What happens if the ground is bad on a distributor?
a bad ground in the distributor system will destroy the modules. check the ground strap or wire inside the cap as pictured above. also check the wiring from the cap to the module, could be a break in the ground wire leading to the module. have you ever switched the coil to a different one?
Do I always carry a spare module in the trunk?
I always carry a spare module in the trunk. When the Chevelle was newer and I was younger, I always had a spare cap, rotor, points and condender in the trunk. The one time I got stuck, I had a tool box and the spare parts to get going again.
