Question about 2004 GMC Envoy

1 Answer

Will a ignition switch cause no spark at the coil over spark plugs? how do i check for ohms resistance at the ignition switch when cranking? 2004 gmc envoy 4.2L

The engine will turn over but want start no spark sometime when cranking after i turn the key loose the starter will keep turning for a few seconds.

Posted by on

Ad

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 652 Answers

Replace the starter http://troubleshootmyvehicle.com/gm/3.5L/how-to-test-the-cop-ignition-coils-1

Posted on Dec 23, 2016

  • 8 more comments 
  • Joe Russell Dec 23, 2016

    is the starter causing no spark at the coil over plugs?

  • woodzowl307 Dec 23, 2016

    http://troubleshootmyvehicle.com/gm/3.5L...

  • woodzowl307 Dec 23, 2016

    Testing the ignition coils on your 3.5L 5 cylinder or 4.2L 6 cylinder is not that hard to do and I'll show you how to do it in this tutorial.

    As you may already be aware, this type of ignition system is known as COP coil system. The acronym COP stands for: Coil On Plug, and refers to the fact that there's an ignition coil sitting on top of each spark plug.

    To help you navigate this article, here are its main points:

    Symptoms of a BAD COP Ignition Coil.
    What Tools Do I Need to Test the COP Coils
    What Does the COP Coil Do/Work?
    Circuit Descriptions of the COP Coils.
    Common Causes of a Misfire Diagnostic Trouble Code (DTC).
    TEST 1: Checking for Misfire Codes.
    TEST 2: Check the Ignition Coil for Spark.
    TEST 3: Swap the ‘No Spark’ COP Coil.
    TEST 4: Cylinder Balance Test.
    TEST 5: Most Common Cause of a P0300.
    Where to Buy a COP Ignition Coil.

    En Espa?ol You can find this tutorial in Spanish here: C?mo Probar Las Bobinas De Encendido (3.5L GM) (at: autotecnico-online.com).
    Symptoms of a BAD COP Ignition Coil

    The most obvious symptom, you'll see when a COP ignition coil goes BAD, is a miss at idle or when you accelerate. This miss being called a misfire in modern tech lingo.

    You're also gonna' see the check engine light (CEL) shining nice and bright on your instrument cluster.

    You'll also see one or several of the following symptoms of a BAD ignition coil (COP coil):

    Diagnostic Trouble Codes:
    P0300: Random Cylinder Misfire.
    P0301: Cylinder #1 Misfire.
    P0302: Cylinder #2 Misfire.
    P0303: Cylinder #3 Misfire.
    P0304: Cylinder #4 Misfire.
    P0305: Cylinder #5 Misfire.
    P0306: Cylinder #6 Misfire.
    Rough idle.
    Smell of raw gasoline coming out of the tailpipe.
    BAD gas mileage.
    Won't pass the emissions test.

    What Tools Do I Need to Test the COP Coils

    The most important tool that you're gonna' need is a spark tester. I'm gonna' recommend one that is the most effective (and the most inexpensive) out there: the HEI spark tester (OTC 6589).

    From personal experience (I work full-time as an automotive tech)... the HEI spark tester is a must have tool. You don't need to interpret the color of the spark or the weakness of it. With the HEI spark tester... if it sparks... the ignition coil is good.

    An HEI spark tester.
    To find out more about this inexpensive yet accurate spark tester, go here: The HEI Spark Tester (The Best Spark Tester On the Market) (this article at: easyautodiagnostics.com).
    If you need to buy one, you can buy it here: OTC 6589 Electronic Ignition Spark Tester
    Scan tool.
    A scan tool is not needed to check the COP coils with the info I'm presenting in this tutorial... but it does come in handy to retrieve the misfire DTC (Diagnostic Trouble Code).
    Don't have one?... check out my recommendation: Abe's Scan Tool Recommendation.
    Wire piercing probe.
    Although this tool is not an absolute must, if you do buy one, you'll realize just how easy it makes testing the voltages inside the wires.
    If you need to see what this tool looks like, you can see it here: Wire Piercing Probe.

    What Does the COP Coil Do/Work?

    In a nutshell, the COP ignition coil's job is to create and deliver spark to the spark plug.

    Its design allows for a more maintenance free ignition system... since you have less moving parts that may wear out and that eventually need to be replaced... like:

    A mechanical distributor assembly.
    Distributor cap.
    Distributor rotor.
    Spark plug wires.

    Now, in case you're really curious about how it works... below is a very brief description of how it works:

    When you turn the Key and crank the engine:
    Power is supplied to circuit A.
    Ground is supplied to circuit C.
    The PCM (Powertrain Control Module = Fuel Injection Computer) gets the crankshaft position signal from the crank sensor.
    The PCM now activates each COP ignition coil.
    This activation signal (Triggering Signal) is supplied to circuit B.
    This Triggering Signal activates an ignition module (also known as the power transistor) within the ignition coil
    The ignition module, in turn, starts to switch the ignition coil 12 Volts On and Off (by interrupting the coil's ground circuit).
    Its the switching On and Off of the primary current (the fancy name for 12 Volts) that causes the COP coil to spark.
    With all 3 signals supplied, the ignition coil now starts to spark.

    Circuit Descriptions of the COP Coils
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    Each COP ignition coil on your engine has 3 wires going to it (or coming out of it).

    Each wire, independent of its specific color, can be identified with a letter.

    These letters are A, B, and C.

    Each one has a specific job to do. Below are their job descriptions.

    IMPORTANT: The color of the middle wire will be different for each COP ignition coil... and this is normal. What will be the same, even if the color of the wire is different, is its job description.
    #1 Ignition Coil Circuits
    Pin Wire Color Description
    A Pink 12 Volt Ignition Power
    B Purple Triggering Signal from PCM
    C Black Ground


    < Prev 1 2 3 4

    ?

  • woodzowl307 Dec 23, 2016

    http://troubleshootmyvehicle.com/gm/3.5L...
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    02 February 2012
    Updated: 08 September 2016
    Written by: Abraham Torres-Arredondo
    Article Id: 162

    Page 1
    Page 2
    Page 3
    Page 4

    Common Causes of a
    Misfire Diagnostic Trouble Code (DTC)

    Before you start your testing, let me make you aware of the most common causes of misfire codes/conditions on the 3.5L 5 cylinder and 4.2L 6 cylinder engine:

    BAD COP ignition coil.
    A BAD COP coil will cause a specific misfire code like P0301, P0302, P0303, P0304, P0305, P0306.
    Leaking intake manifold gaskets.
    The intake manifold gaskets are made out of rubber (they're oversized rubber O-rings) and over time they hardened and shrink.... loosing their sealing ability and usually causing a Random Misfire Code P0300.
    Leaking valve cover gasket.
    A leaking valve cover gasket will let engine oil into the spark plug well and inundate the spark plug and coil boot with engine oil.
    This will eventually lead to carbon tracks on the spark plug and coil boot that'll cause a misfire.
    Incorrectly gapped spark plugs.
    Broken spark plug. Specifically, a cracked porcelain insulator.
    Water in the spark plug wells caused by washing the engine.

    TEST 1: Checking for Misfire Codes
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    The very first thing you need to do, is to connect your scan tool to your vehicle and check for misfire codes.

    Why? Because the misfire code will help you in identifying which cylinder is the one that could have a BAD ignition coil... and knowing which ignition coil to test is half the diagnostic battle.

    Now, if you don't have a scan tool, you can still use the info in this tutorial... but you'll need to do a cylinder balance test. For more info on this, go to: TEST 4.

    Choose from one of the cases below:

    CASE 1: You have a misfire code - The next step is to find out if this misfire code is being caused by a BAD COP ignition coil. Go to TEST 2.

    CASE 2: You have a P0300 Misfire Code - This means that whatever is causing the misfire condition, is affecting all of the engine cylinders and not just one.

    This code, the (P0300) usually rules out a BAD COP ignition coil as the culprit. For more info on troubleshooting a P0300, go to: TEST 5.

    CASE 3: You DO NOT have any misfire codes - This means that the rough idle that you're experiencing in your vehicle is not being caused by a BAD COP coil.

    Now, unfortunately, this is not an absolute truth.. cause you could have a BAD COP coil. What I suggest you do, is to do a cylinder balance test (TEST 4) and/or a thorough visual inspection of the spark plugs, COP coils to see if:

    Spark Plugs are not:
    Soaked in oil (leaking valve cover gasket).
    Soaked in water (from power washing the engine).
    Cracked or broken.
    Center electrode's gap is filled/covered with Carbon (from the cylinder burning oil).
    COP coils are not:
    Soaked in oil (leaking valve cover gasket).
    Soaked in water (from power washing the engine).
    Cracked or broken.

    If all of the above checks out... I would suggest an engine compression test. You can find the test here: How to Check Engine Compression (GM 3.5L, 4.2L).
    TEST 2: Check the Ignition Coil for Spark
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    The very first thing you need to do, is check to see if the COP ignition coil is sparking or not.

    My instructions below call for an HEI spark tester and if you don't have one.. you may be wondering if you can use any other type of spark tester.

    And the answer is yes you can use any type of spark tester you want or have. The main reason I use and recommend the HEI spark tester is because this bad boy is accurate (and you don't have to worry about interpreting the color of the spark).

    OK, to get your COP ignition coil diagnostic going, this is what you need to do:

    Remove the ignition coil from its place on the valve cover.
    Connect an HEI spark tester to the ignition coil.
    Ground the HEI spark tester with a battery jump start cable directly on the battery negative terminal.
    When everything is set up, have a helper crank the engine while you observe the spark tester.
    The spark tester will do one of two things: spark or Not spark.

    Let's take a look at your test results:

    CASE 1: You got spark- This tells you that ignition coil is OK.

    So, if you have a misfire code for the specific engine cylinder this COP coil belongs to... then you need to look at the following things:

    Oil dripping onto the spark plug and COP coil boot from the valve cover gasket.
    Spark plugs for carbon tracks.
    Low engine compression in this cylinder.

    CASE 2: You DID NOT get spark- This usually means that the COP ignition coil is BAD... there's one more thing that you need to do (to make sure that the COP coil is truly BAD).

    And this is to make sure that the COP ignition coil that did not spark is getting all three signals from its connector. We can easily accomplish this by simply swapping a good and sparking COP coil in place of the one that's not sparking and repeating this test. For this test, go to TEST 3.

    1 2 3 4

  • woodzowl307 Dec 23, 2016

    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    02 February 2012
    Updated: 08 September 2016
    Written by: Abraham Torres-Arredondo
    Article Id: 162

    Page 1
    Page 2
    Page 3
    Page 4

    TEST 3: Swap the ‘No Spark’ COP Coil
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    OK, in TEST 2 you confirmed that you do have one COP coil that's not sparking...

    ... In this test step, you're gonna' place one of the other COP coils (that is sparking) in the place of the one that isn't.

    If the good COP ignition coil sparks in its new place, then you now know beyond a shadow of a doubt that the COP coil is getting all 3 signals from its connector.

    This is what you'll need to do:

    Disconnect and remove the COP ignition coil that did not spark.
    Choose one of the other COP coils that is sparking and remove it from its place.
    If you need to make sure that this COP ignition coil is sparking... you can tested with your spark tester.
    Once the good COP coil is removed, place it in the location of the BAD COP ignition coil.
    Next, connect the HEI spark tester to this COP coil.
    Ground the HEI spark tester with a jump start cable directly on the battery negative terminal.
    Now, place the BAD COP ignition coil in the location of the good one you just removed and bolt it down.
    Once everything is ready, have your helper crank the engine.
    What you need to see is:
    That the good COP coil is still sparking
    This would confirm that the 3 signals are present in the COP coil connector.

    Let's take a look at your test results:

    CASE 1: The COP ignition coil sparked- This tells you that the COP coil that did not spark in TEST 2 is BAD and needs to be replaced.

    Here's why: By placing a good and sparking ignition coil in place of the BAD one and having spark come out of the good one... then this proves that:

    Circuit A wire is providing power (10 to 12 Volts).
    Circuit B wire is providing the PCM's Triggering Signal (known as the IC (Ignition Control) Signal).
    Circuit C wire is providing ground.

    If you need/want to save a few bucks and buy a good quality COP coil for your vehicle, look at this section: ‘Where To Buy a COP Ignition Coil’ for my suggestion.

    CASE 2: The COP ignition coil DID NOT spark- This tells you that the reason why the COP coil did not spark is because it's lacking one of the 3 signals it needs to spark.

    The next step for you is to:

    Check that Circuit A wire is providing power (10 to 12 Volts).
    Check that Circuit B wire is providing the PCM's Triggering Signal (known as the IC (Ignition Control) Signal).
    Check that Circuit C wire is providing ground.

    TEST 4: Cylinder Balance Test

    A cylinder balance test will help you determine which engine cylinder is the one missing (misfiring).

    In a nutshell, the cylinder balance test involves starting the engine, letting it idle, and then unplugging one COP ignition coil at a time to see which cylinder is ‘dead’.

    By ‘dead’ I mean not contributing to engine power. Now, let me go into more specifics: If an engine cylinder is getting both spark, fuel, and has good compression... and you unplug the COP coil connector, you're gonna' visibly see the engine shake more.

    In other words, disconnecting the COP coil (while the engine is running) will cut power from that cylinder and you'll see/feel a difference.

    NOTE: There's one very important thing to keep in mind when doing a cylinder balance test that involves disconnecting the COP coil connector... and this is that you can't spend too much time with the engine idling with the COP coil disconnected.

    Why? Because this will let too much unburned fuel overload the catalytic converter, and this is never a good idea.

    OK, this is what you need to do:

    Start the engine and let it idle.
    Once the idle has stabilized, briefly unplug COP ignition coil for cylinder #1.
    If the cylinder is ‘dead’
    You won't see/feel a difference in the engine's idle quality.
    If the cylinder is NOT ‘dead’
    You will see/feel a difference in the engine's idle quality.

    Let's take a look at your test results:

    CASE 1: The cylinder balance test identified a ‘dead’ cylinder- Now that you have identified the cylinder with the misfire, the next step is to check and confirm that it's not being caused by a BAD COP (Coil-On-Plug) ignition coil.

    This involves checking the COP ignition coil for spark... you can now start with: TEST 2.

    CASE 2: The cylinder balance test DID NOT identify a ‘dead’ cylinder- This tells you that you don't have a specific ‘dead’ cylinder.

    Now, if your vehicle is experiencing a rough idle condition... then it's something that's affecting all of the cylinders and not just one. My suggestion in this case is to look at: TEST 5.

    1 2 3 4

  • woodzowl307 Dec 23, 2016

    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    02 February 2012
    Updated: 08 September 2016
    Written by: Abraham Torres-Arredondo
    Article Id: 162

    Page 1
    Page 2
    Page 3
    Page 4

    TEST 3: Swap the ‘No Spark’ COP Coil
    Ignition Coil-On-Plug (COP) Test (GM 3.5L, 4.2L)

    OK, in TEST 2 you confirmed that you do have one COP coil that's not sparking...

    ... In this test step, you're gonna' place one of the other COP coils (that is sparking) in the place of the one that isn't.

    If the good COP ignition coil sparks in its new place, then you now know beyond a shadow of a doubt that the COP coil is getting all 3 signals from its connector.

    This is what you'll need to do:

    Disconnect and remove the COP ignition coil that did not spark.
    Choose one of the other COP coils that is sparking and remove it from its place.
    If you need to make sure that this COP ignition coil is sparking... you can tested with your spark tester.
    Once the good COP coil is removed, place it in the location of the BAD COP ignition coil.
    Next, connect the HEI spark tester to this COP coil.
    Ground the HEI spark tester with a jump start cable directly on the battery negative terminal.
    Now, place the BAD COP ignition coil in the location of the good one you just removed and bolt it down.
    Once everything is ready, have your helper crank the engine.
    What you need to see is:
    That the good COP coil is still sparking
    This would confirm that the 3 signals are present in the COP coil connector.

    Let's take a look at your test results:

    CASE 1: The COP ignition coil sparked- This tells you that the COP coil that did not spark in TEST 2 is BAD and needs to be replaced.

    Here's why: By placing a good and sparking ignition coil in place of the BAD one and having spark come out of the good one... then this proves that:

    Circuit A wire is providing power (10 to 12 Volts).
    Circuit B wire is providing the PCM's Triggering Signal (known as the IC (Ignition Control) Signal).
    Circuit C wire is providing ground.

    If you need/want to save a few bucks and buy a good quality COP coil for your vehicle, look at this section: ‘Where To Buy a COP Ignition Coil’ for my suggestion.

    CASE 2: The COP ignition coil DID NOT spark- This tells you that the reason why the COP coil did not spark is because it's lacking one of the 3 signals it needs to spark.

    The next step for you is to:

    Check that Circuit A wire is providing power (10 to 12 Volts).
    Check that Circuit B wire is providing the PCM's Triggering Signal (known as the IC (Ignition Control) Signal).
    Check that Circuit C wire is providing ground.

    TEST 4: Cylinder Balance Test

    A cylinder balance test will help you determine which engine cylinder is the one missing (misfiring).

    In a nutshell, the cylinder balance test involves starting the engine, letting it idle, and then unplugging one COP ignition coil at a time to see which cylinder is ‘dead’.

    By ‘dead’ I mean not contributing to engine power. Now, let me go into more specifics: If an engine cylinder is getting both spark, fuel, and has good compression... and you unplug the COP coil connector, you're gonna' visibly see the engine shake more.

    In other words, disconnecting the COP coil (while the engine is running) will cut power from that cylinder and you'll see/feel a difference.

    NOTE: There's one very important thing to keep in mind when doing a cylinder balance test that involves disconnecting the COP coil connector... and this is that you can't spend too much time with the engine idling with the COP coil disconnected.

    Why? Because this will let too much unburned fuel overload the catalytic converter, and this is never a good idea.

    OK, this is what you need to do:

    Start the engine and let it idle.
    Once the idle has stabilized, briefly unplug COP ignition coil for cylinder #1.
    If the cylinder is ‘dead’
    You won't see/feel a difference in the engine's idle quality.
    If the cylinder is NOT ‘dead’
    You will see/feel a difference in the engine's idle quality.

    Let's take a look at your test results:

    CASE 1: The cylinder balance test identified a ‘dead’ cylinder- Now that you have identified the cylinder with the misfire, the next step is to check and confirm that it's not being caused by a BAD COP (Coil-On-Plug) ignition coil.

    This involves checking the COP ignition coil for spark... you can now start with: TEST 2.

    CASE 2: The cylinder balance test DID NOT identify a ‘dead’ cylinder- This tells you that you don't have a specific ‘dead’ cylinder.

    Now, if your vehicle is experiencing a rough idle condition... then it's something that's affecting all of the cylinders and not just one. My suggestion in this case is to look at: TEST 5.

    1 2 3 4

  • Joe Russell Dec 23, 2016

    there is 10 to 12 volts at the Circuit A wire but i don't how to Check that Circuit B wire to see is it providing the PCM's Triggering Signal how do i check for signal? Circuit C wire is providing ground. when i check for spark there is no spark at none of the coils.

  • Joe Russell Dec 23, 2016

    there is 10 to 12 volts at the Circuit A wire but i don't know how to Check that Circuit B wire to see is it providing the PCM's Triggering Signal how do i check for signal? Circuit C wire is providing ground. when i check for spark there is no spark at none of the coils.

  • woodzowl307 Dec 23, 2016

    Replace ignition switch

  • Joe Russell Dec 23, 2016

    where is the ignition switch located what i have to do to replace it? thank you for the information you have share with me it was a lot of help to me.

×

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Goodluck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

No spark from coil to distrubuter


Disconnect the ignition coil output wire at the distributor cap.
Connect a spark plug to the end of the ignition coil output wire which you just disconnected.
Connect a ground wire to the threaded portion of the spark plug.
Disconnect the ignition coil ground wire from the negative terminal on the coil (Green Wire).
Connect one end of a ground wire to the ignition coil negative terminal.
Turn the ignition switch to the ON position.
Tap the other end of the ignition coil ground wire jumper on an good grounding point (for example the battery negative terminal) and look for sparks at the spark plug that correspond to the frequency of your tapping of the ground wire.
If you have a good spark at the spark plug, the ignition coil is good.
If you don't get a good spark, check for approximately 12 VDC from the coil positive terminal (black wire) to ground with the ignition switch in the ON position. You should also get approximately 12 VDC from the coil negative terminal (Green wire) to ground
Ignition Coil Resistance Check

In addition to the test above, you may elect to perform an ignition coil resistance check as confirmation of the coil's condition.

Check the ignition coil primary coil resistance by connecting an ohmmeter between the positive (Black wire) and negative (Green wire) terminals on the coil. The resistance should be 0.4 to 0.6 ohms.
Check the ignition coil secondary coil resistance by connecting an ohmmeter between the coil output terminal and the ignition coil negative terminal. The resistance should be 5000 to 7200 ohms.

You may have a bad coil or bad ground or wire connection

Jan 23, 2017 | Cars & Trucks

3 Answers

Engine stop


If theres no spark from the spark plugs then you would have to replace them?

Jul 12, 2008 | 1993 Toyota Corolla

1 Answer

1997 buick lesabre runs good but hard to start


Hard Start
Checks
Action
Definition: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.
Preliminary
• Refer to the Powertrain On Board Diagnostic (OBD) System Check .
• Refer to Important Preliminary Checks .
• Refer to Visual/Physical Checks .
• Search for bulletins.
Sensor/System
• Check Engine Coolant Temperature (ECT) sensor for being shifted in value. Connect a Scan Tool and compare the Engine Coolant Temperature with the Intake Air Temperature on a cold engine. The ECT and IAT should be within ± 3°C (5°F) of each other. Check the resistance of the ECT sensor if the temperature is out of range with the IAT sensor. Refer to Temperature vs Resistance . If the ECT sensor resistance is not within the specification, refer to DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage or DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage .
• Check the throttle body inlet screen for foreign objects or damage that may affect the MAF sensor airflow sample. Refer to Throttle Body Assembly Replacement .
• Use a scan tool in order to check the IAC operation. Refer to Idle Air Control (IAC) System Check .
• EGR system. Check the for the following conditions:
- EGR pipes and adapter for vacuum leaks.
- Remove the EGR valve and check for a stuck open pintle. Refer to Exhaust Gas Recirculation Valve Replacement .
Fuel System
• Check the fuel pump relay circuit for proper operation. Refer to Fuel Pump Electrical Circuit Diagnosis .
• Check for incorrect fuel pressure. Refer to Fuel System Pressure Test .
• Check the fuel injectors. Refer to Fuel Injector Solenoid Coil Test .
• Check for fuel contamination. Refer to Alcohol/Contaminants-in-Fuel Test .
Ignition System
• Check for proper ignition voltage output by using the following steps:
- Clip the spark tester J 26792 to engine ground.
- Connect one end of a spark plug wire to the spark tester while leaving the other end of the spark plug wire to the coil being tested.
- Connect one end of another spark plug wire to the other coil tower.
- Connect the other end of the spark plug wire to ground.
- Crank the engine while observing the spark tester. A crisp blue spark should be observed.
- Repeat the above steps for each coil.
• If an adequate spark is not present at the coil(s), check for the following conditions:
- Coil(s) - Cracks, carbon tracking/arcing, or a resistance value outside the specified range.
Coil Resistance
5000 - 8000 ohms (5K - 8K ohms)
- Spark Plug wires
• signs of arcing/cross
• cracks
• carbon tracking
• firing
• plug boot damage
• pinched or improper routing
• high resistance
- Spark plug wire resistances should measure less than the specified value.
VIN 1 Spark Plug Wire Resistance
7000 ohms (7K ohms).
VIN K Spark Plug Wires Resistance
10000 ohms (10K ohms).
Important: Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition components will arc to ground when a secondary component is malfunctioning.
- Defective module.
- Ignition System Wiring - Loose ignition module feed or ground connection, or damaged system wiring.
• Remove spark plugs and check for the following conditions:
- Fouled plugs
- Cracks
- Wear
- Improper gap
- Burned or damaged electrodes
- Improper heat range or reach
• If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.
Engine Mechanical
• Excessive oil in combustion chamber-Leaking valve seals. Refer to Engine Mechanical.
• Low cylinder compression. Refer to Engine Mechanical.
• For incorrect basic engine parts. Inspect the following:
- Cylinder heads
- Camshaft and valve train components
- Pistons, etc.
- Refer to Engine Mechanical.

Nov 17, 2016 | 1997 Buick LeSabre

1 Answer

How do I test my 2002 jeep liberty coil ignition. I need to find out which one is bad


Use a multi-meter, turn it to ohms, and check the resistance in the coil circuit. All should be similar- showing resistance of only a few ohms, typically. High resistance in the circuit indicates a bad coil.

Or you could just check for spark on each coil to plug wire. Check the spark at each plug wire end terminal with the engine cranking over. If spark is a strong, blue spark, that coil is probably good.

Sep 12, 2015 | Jeep Cars & Trucks

1 Answer

I have a 2001 roadking police bike. it has no spark. the bike cranks fine the fuel pump works, I checked all fuesess relays. checked the ckp sensre for metal ,checked the pickup senser metal. checked




Are the plugs installed because without compression you will not get ignition/spark.

Are there any codes set???

Is the ignition fuse okay??? Is ECM fuse okay?

Of course first you need power to the coil which should be there whenever the ignition and run switches are on if so see below:


Are the plugs installed

Remove the coil. THEN set your ohmmeter scale to RX1 and place ohmmeter leads on the primary coil windings A (front of coil) to B (middle of coil), B to C (front of coil) and check for primary coil winding resistance which normal resistance range is 0.5-0.7 ohms. If primary resistance is not within this range check out test results below.


Ignition Coil Secondary Circuit Test

With the ignition coil removed from the motorcycle and the ohmmeter set to the RX1K scale place the ohmmeter leads on the secondary coil windings B (middle terminal) to

R (rear secondary terminal/socket), B to F (front secondary terminal/socket) and check for secondary coil winding resistance which normal resistance range will be 5.5-7.5K ohms. If secondary resistance is not within this range check out test results below.


Test Results

A low resistance value indicates a short in the coil winding which requires coil replacement.


A high resistance value might indicate that there is some corrosion/oxidation of the coil terminals requiring the coil terminals to be cleaned and the resistance test then repeated and if after the test is repeated the resistance is still high after the terminals were cleaned the coil must be replaced.

If there is an infinite ohms or no continuity) resistance value the coil is open and must be replaced.


If you have spark, it sounds like either the sensor in the timing cavity of the engine is bad or the electronic ignition unit is bad.


Oct 18, 2014 | Cars & Trucks

1 Answer

My 92 explorer has no spark


Hi, here are some tests you can do to diagnose the problem. Please let me know if you have questions.

First, use a voltmeter or 12 volt test light to check for power on the red wire going to pin 8 of the ignition control module when the key is on. The module is in the left front corner of the engine compartment.

jturcotte_2441.gif
jturcotte_2440.gif

If there is no power, the problem is the ignition switch or EEC relay. If there is power, next, check the ignition coil as listed below.

IGNITION COIL TESTINGPrimary and Secondary Circuit Tests
  1. Turn the ignition switch OFF , disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
  2. Check for dirt, corrosion or damage on the terminals.

PRIMARY RESISTANCE
  1. Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:

Except 2.3L, 2.5L and 5.0L engines


B+ to Coil 1 B+ to Coil 2 B+ to Coil 3
The resistance between all of these terminals should have been between 0.3-1.0 ohms. If the resistance was more or less than this value, the coil should be replaced with a new one.

SECONDARY RESISTANCE


jturcotte_2439.gif

Fig. Fig. 1: Engine ignition coil harness connections-3.0L and 4.0L engines

  1. Measure, using the ohmmeter, and note the resistance between each corresponding coil terminal and the two spark plug wire towers on the ignition coil. The coil terminals and plug wires towers are grouped as follows:
Except 2.3L, 2.5L and 5.0L engines

Terminal 3 (coil 1)-spark plugs 1 and 5 Terminal 2 (coil 3)-spark plugs 2 and 6 Terminal 1 (coil 2)-spark plugs 3 and 4

If the coils test good, move on the the crankshaft sensor.
Using a DVOM set to the DC scale to monitor less than 5 volts, measure the voltage between the sensor Cylinder Identification (CID) terminal and ground by backprobing the sensor connector. If the connector cannot be backprobed, fabricate or purchase a test harness. The sensor is okay if the voltage reading varies more than 0.1 volt with the engine running at varying RPM. (check both the blue and gray wires at the ignition module with the engine cranking.)



jturcotte_2442.gif

Fig. Fig. 3: CKP sensor wire harness connections for the 4.0L (VIN X and E) engines


If there is power and both the coils and sensor check good, replace the ignition control module.

Oct 27, 2011 | Cars & Trucks

1 Answer

Dodge neon 1996.it has no spark.already le intal crank position sensor and cam sensor.and yet has no spark.that may be.


remove electrical plug from coil,with test light check tosee if u are getting power to the coil with the key on.(remove fuel relay during the testing) if there is power to coil then check resistence on coil. with plug still disconnected.take ohm meter and connect to the two outside plugs to check ohm resistance 0.45 - 0.65 ohms then use ohm meter to check secondary resistance.connect ohmmeter across the two secondary terminals of each coil. resistance 11.5-13.5 k-ohms. if all checks out test wires and plugs. hope this will help!!!

Apr 20, 2010 | Dodge Neon Cars & Trucks

1 Answer

Truck just all off a sudden wont start. Put new


MAKE SURE DISTRIBUTOR COIL IS GETTING POWER.IF NOT.CHECK IGNITION FUSE.IF FUSE IS GOOD AND COIL IS GETTING POWER.REMOVE COIL AND CHECK THE COIL PRIMARY RESISTANCE USING A DIGITAL VOLTMETER. IT SHOULD BE 0.1 OHM.SECONDARY RESISTANCE SHOULD BE 5000 TO 25000 OHMS..IF COIL PASS ITS THE IGNITION MODULE.IF COIL FAILS.COIL IS BAD.

Sep 05, 2009 | GMC G2500 Cars & Trucks

1 Answer

The car will crank but does not have fire going to the coil pack


did you do a spark test?
This could be a number of things, your crankshaft sensor, coils or ignition module.
check the coils
  1. Remove the ignition coil(s).
  2. Using an ohmmeter, check the resistance between the primary terminals on the underside of the coil. The resistance should be 0.50-0.90 ohms.
  3. Check the resistance between the secondary terminals. It should be 5,000-10,000 ohms.
  4. If the coil failed either test, replace the coil.

Jul 25, 2009 | 1995 Chevrolet Cavalier

1 Answer

How do you test the ignition module and ignition coil no fire in spark plug gmc savana 1999 5.0l 2500


to test the ignition coil hook a meter to the respective ends. there should be infiinite resistance in ohms on the coil

Mar 20, 2009 | 2000 GMC Savana

Not finding what you are looking for?
2004 GMC Envoy Logo

Related Topics:

48 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts

yadayada
yadayada

Level 3 Expert

76846 Answers

Freddy

Level 3 Expert

1311 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22246 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...