The ignition module of your vehicle is the heart of your entire ignition system. The ignition module has a direct impact on the performance of the engine. The module resembles a small electrical box with a wire harness. It is usually located on or in the distributor housing in domestic vehicles, and on the firewall or wheel-well in foreign vehicles.
Like all automobile components, the ignition module will eventually deteriorate and break. However, you can anticipate and prepare for the failure. These tips will help you recognize the two most common symptoms of ignition module failure.
Overheating is a common indicator that you could be having an ignition module problem. Ignition modules that are overheating will soon completely cease to function and in the meantime can cause cause electrical shorts, engine stuttering, lower gas mileage, power loss, stalling, and gasoline odors in the exhaust. You can test for overheating while the car still runs. Idle the engine for 30 minutes, and then tap the module with a screwdriver. The car may stall, which would strongly suggest that ignition control module may be the cause of the overheating you're experiencing.
If you are caught with an overheated module in an emergency situation, you can cool it down with ice water, engine coolant, or refrigerant fluid. However, this is a temporary solution only to be used as a last resort until you can reach repair facilities.
GMC 5.7L/350 Chevy small block Gen I Ignition Modules
If your vehicle stalls unexpectedly during operation and will not start again, it is likely because of loose or corroded electrical connections in the ignition module. In this case, check the switch, clean oxidized terminals, and replace broken wires if necessary. If you cannot start the car, you need to test the ignition control module using a light timing tester to check the output of the module.
Connect the timer to the positive terminal of the battery and check the continuity of the black output wire while cranking the starter. If the light blinks, the module is good. If the light is blank or constant, the module is bad. Before you attempt to replace the control module, you must rule out other ignition system components.
The module is expensive and replacing it is a laborious process. Check the ignition coil for a spark.Display Options. Already know the part number you need?
CHEVROLET 5.7L/350 Ignition Modules
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Ignition Module Failure
United States delivery. Recent Vehicles. Refine results by: Current Vehicle Recent Vehicles. Recently Searched. Show Recent Vehicles. X Welcome International Customers!This is one of the easiest GM ignition control modules to test.
This article will take you step by step through the whole process of diagnosing and troubleshooting a bad ignition control module and ignition coil. If you're GM car or truck starts and runs, this article will not help you.
Since so many things can cause your vehicle to not start like a bad fuel pump, etc. At the end of this tutorial I've included a list of other tutorials that will help you diagnose a Cranks but Does Not Start Condition in case it's not ignition system related. Specifically, the ignition coil will not spark. For this particular reason and before you follow the test procedures in this tutorialyou need to verify that the ignition coil IS NOT sparking by connecting a spark tester directly on the ignition coil's tower and cranking the engine.
This is a pretty easy test, but it must be done with a spark tester. In this scenario, your vehicle will start and run most of the time, but every now and then it won't. If this is the case, you'll have to wait till the car or truck does not start to use the tests in this article. You don't need a whole lot of stuff, heck, you don't even need a scan tool tho' a scan tool is important to have, but not for this article! Here is what you're gonna' need to effectively use the information in this article:.
Here is a little background information to help you diagnose the ignition control module ICM or the ignition coil. In a nutshell, when your turn the key and start cranking the engine:. If everything is working properly, the engine will start. Now, the important thing to know is that the PCM controls the creation of spark from the get-go crank up and at all engine speeds thru' the ignition control module ICM.
The really cool thing about this type of ignition system is that all of these signals IC Signal and the Switching Signal can be tested easily with some very simple tools. The ignition control module ICM has 4 wires coming out of it. Below are the descriptions of what each circuit does. Each circuit is identified by a letter, and this is the same letter that you will find on the ignition module's connector.
The ignition coil on your car or truck may have or may not have 3 wires coming out of it.Not only that, you don't need any expensive tools to do it.
You'll test the following components: ignition control module, spark plug wires, distributor cap and rotor and ignition coil and pick up coil of the GM 4. Before we start, just want to remind you that since this is an On Car test, do not remove the ignition control module from the distributor or the ignition coil.
Some of the images in this article show them off of the vehicle just to make it easier to explain their testing process. The typical ignition system circuit diagram for the 4.
In a nutshell, when you crank up the engine and the ignition system is working properly :. The tests that you're gonna' learn in this article only deal with steps 1 thru' 4, among several tests. But whether your car or truck does not start or starts but runs with a misfire, this is the tutorial you need to diagnose it! The following are usually the most common symptoms of a bad ignition control module on this type of GM distributor mounted ignition control module:.
The following are usually the most common symptoms of a bad spark plug wires, or a bad distributor cap and rotor on this type of GM distributor mounted ignition control module:.
The following is usually the most common and only symptom of a bad ignition coil on this type of GM distributor mounted ignition control module:. All Tutorials: 4. This material may not be reproduced without the author's consent. Applies To:. Chevrolet Vehicles:.
GMC Vehicles:. Oldsmobile Vehicles:. Pontiac Vehicles:. Do NOT follow this link or you will be banned from the site! Hate Spam.Ignition module failure is no joke because it often leaves you stranded. The complaint is the engine cranks normally, but does not start.
The cause of an ignition control module failure is often associated with age and damage from heat buildup. The correction for this issue becomes the replacement of the failed component. Here in this brief article we'll talk about three popular generations of control modules known for a high failure rate.
This article focuses on General Motors automobiles from the last 30 years. We start on covering vehicles from the mids and progress through the model year. When I say high and dry I'm talking about a vehicle that cranks around, but will not fire up. Most of the original modules installed in Chevrolet distributors from the mids through the mids shared the same solid-state design. General Motors designed them to last for the life of the vehicle. However the 4. It's not uncommon the find a Chevrolet Silverado pickup from the early 90s with more thanmiles on the 5.
The same can be said for the Chevrolet Blazer or S pickup truck that carries the 4. These engines need ignition modules before they head to the junkyard.
On a technical note, make sure you apply dielectric grease to the heat sink before you install the new part. We have more on that below. These old distributors let air in through the bottom and vent it through the top of the distributor cap.
If these become clogged corrosion and heat buildup can cook the new module. In General Motors redesign the ignition module discussed above. They used it on about 10 years worth of vehicles. With that said, these parts didn't hold up as well or as long as the ignition modules from the previous generation.
These parts found their way into the same V-8 and V-6 engines mentioned above. However, they now call them Vortec motors. Some popular vehicles with high sales figures carried these types of ignition modules. This also includes the pickup trucks and cargo vans.
What's interesting about this common ignition module failure is the way it goes out. When the second generation modules go bad the vehicle starts up and runs good until it gets hot.
After the engine cools down the vehicle might restart and run fine until it gets hot again. This cycle happens over and over again until you replace the component. Intermittent malfunctions become hard to find, but the way this module fails is common knowledge around experienced mechanics. Sidebar: In some cases the Vortec plastic distributor fails before the ignition module. In the early 90s General Motors started to do away with the distributor, cap and rotor we all loved since the turn-of-the-century.
GM decided they didn't need all those moving parts. Now they would receive data from a crankshaft and camshaft position sensor and use this information to fire each plug directly. Hence, direct ignition became popular.To troubleshoot a Chevy engine expediently, you must figure out if the problem is the ignition, electrical, fuel or mechanical.
If the engine is not making noise i. Check for a fuel problem by spraying carburetor cleaner into the carburetor. Start the vehicle. If the vehicle starts, there is a fuel problem. If you have a mechanical fuel pump and the lines are not clogged, replace the mechanical pump. If you have an electric fuel pump, check the relay.
If the relay is bad, replace it. If the relay is good, check for power at the electric fuel pump. Check the ignition by checking for spark. Pull any spark plug wire off a spark plug. Stick an extra spark plug into the end of the wire and lay it on the valve cover or intake manifold chrome valve covers will not work for thisyou must be able to create a good ground on metal. Watch for spark at the spark plug while a helper turns the engine over.
If you see spark, the ignition is fine. If not, remove the distributor cap to check for worn contacts or a worn rotor. Make sure the points are adjusted properly. If you do not have a feeler gauge to check the points, a matchbook cover is the same thickness. Turn the key on.
You should see 12 volts. If you do not see voltage going into the coil, check the ignition switch and the wiring between the ignition switch and the coil. Check the battery with a voltmeter by touching the positive terminal with the positive lead of the voltmeter and the negative battery terminal with the negative lead of the voltmeter.
If the voltage is below Start the vehicle after charging the battery. Touch the battery terminals with the respective voltmeter leads as outlined in the previous step.
GMC 5.7L/350 Chevy small block Gen I Ignition Coils
If the voltmeter shows Shut the vehicle off. Have a helper start the vehicle while you are watching the voltmeter.GMC Ignition Coil & Ignition Control Module (ICM) - Re-Thermal + Cleaning - Car / Truck S10 Chevy
If the voltmeter drops below If the starter relay is good, the starter is bad and needs to be replaced. This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Works, contact us. Troubleshooting a Chevy Engine by Cayden Conor.
Check Battery and Alternator Check the battery with a voltmeter by touching the positive terminal with the positive lead of the voltmeter and the negative battery terminal with the negative lead of the voltmeter. About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.Display Options.
Already know the part number you need? Click here to enter them directly into your cart. If you are an international customer who ships to a US address choose "United States delivery" and we will estimate your ship dates accordingly.
If you are an international customer and would like to change the currency that prices are displayed in, you can do so here. What is this? Loading Tomorrow Estimated International Date Loading Today. Low Price Guarantee. We're so confident in our low prices, we offer a Beat-a-Price Guarantee: We'll beat our competitors' advertised prices on any identical, in-stock product proof of advertised price required! GMC 5. Vertical Navigation Horizontal Navigation.
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