After part replacements, spark plugs do not work
My car does not seem to be getting fire to the spark plugs and it will not start. I installed the control module, distributor cap, rotor, ignition coil, spark plugs, and spark plug wires. I can’t figure out why the spark plugs are not getting any spark. My car does turn over, but it just will not start. What can I do next to get the spark plugs functioning normally?
Experienced mechanics share their insights in answering this question :
If you have a Check Engine Light on, first check for those codes to determine what engine management thinks is going on. If no trouble code, check the ignition fuse behind the driver side kick panel (carpeted panel at foot level on the left – for left-hand drive vehicles). If the engine is spinning quickly, and doesn’t appear to be meeting any resistance (as a motor with good compression would have), you may have a broken timing belt. If so – STOP, call a professional mechanic, like a certified technician from YourMechanic for help.
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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 you see a good spark at the coil, but not at the spark plug, then the problem may be caused by either a bad distributor cap, rotor, or carbon point and/or spring, or plug wires.
If the ignition coil does not have spark, it`s time to check its wires. Use a test light to check the continuity on the signal wire and power wire on the ignition coil. If both wires are functional but the coil fails to produce spark, the ignition coil or the ignition control module is bad.
When the high voltage produced by the ignition system is applied between the center electrode and ground electrode of the spark plug, the insulation between the electrodes breaks down, current flows in the discharge phenomenon, and an electrical spark is generated.
Place the metal screwdriver near the electrode of the distributor. It should not touch the electrode. Step away from the hood and have someone watch the arc while the ignition is turned on. If there is an arc, it is firing.
your engine is misfiring: if the distributor isn`t providing enough juice to the spark plugs, it can cause your engine to misfire, which typically feels like the engine is stumbling. it`s usually caused by incomplete combustion. typically, a failing distributor will cause a misfire on all cylinders.
Ignition Control Modules fail when they overheat. The most common symptom of failure is a no-start. A failing module may give other symptoms, such as engine stuttering and stalling, before it stops working.
To check if the ignition module is getting voltage, set the multimeter to AC voltage (VAC) reading and check for voltage at the thermostat input or 24VAC input to the Ignition Control Module. You should get a reading of 24VAC with respect to common or ground.
Spark plugs usually require voltage of 12,000–25,000 volts or more to `fire` properly, although it can go up to 45,000 volts. They supply higher current during the discharge process resulting in a hotter and longer-duration spark.
The Ignition Coil
These coils are called windings. One winding is called the primary winding, the other is the secondary. The primary winding gets the juice together to make a spark and the secondary sends it out the door to the distributor.
There could be a crack in the cap, but most of the time the spark occurs due to lack of connection. Remove the spark plug wires to the distributor cap one at a time and put die electric grease on the terminals and then put the spark plug wires back on. Allow the one hour for the die electric grease to seal up tight.
Weights and springs inside the distributor rotate and affect the timing advance according to engine speed by altering the angular position of the timing sensor shaft with respect to the actual engine position. This type of timing advance is also referred to as centrifugal timing advance.
Switch on ignition, but do not crank the engine over. Hold the coil HT lead near the tip of the rotor, and flick the points open. You will get spark as the points open. If the spark jumps from the HT lead to the rotor, then the rotor is bad and is grounding the spark to the rotor drive shaft.
Distributor Cap
Distributor caps also assist in sending electrical current from the ignition coil to the spark plugs. Distributor caps are considered wear items that need to be periodically replaced, as a bad distributor cap can impact engine performance and gas mileage.
Cracked distributor cap
Cars that don`t have ignition coils on their spark plugs have a distributor cap and a wire set that disperse the electrical pulse to the spark plugs. If the cap is cracked, it allows moisture to creep in, which causes the electrical spark to jump to the wrong cylinder, causing a backfire.
Pull the coil wire from the distributor and hold it near a ground. Again, have your assistant crank the engine and look for spark from the coil lead. If you have spark, you likely have a problem with your distributor rotor or cap, so you may want to replace them.
Distributor ignition coils Distributor ignition coils have a high-voltage dome which is connected to the ignition distributor via a high-voltage cable. They are primarily used in vehicles with rotating high-voltage distribution.
A dead battery is one of the most common reasons why your car won`t start. Check the battery terminals for corrosion and clean them using a wire brush or battery cleaning solution. If the battery is old or damaged, it may need to be replaced entirely.
The Ignition Control Module controls the firing of the ignition coil/s so it can create the voltage the spark plugs need to ignite the air/fuel mixture in the engine cylinder.
What kills ignition coils is location; being mounted in one of the hottest, most vibration prone and dirtiest parts of the engine. Modern ignition coils are typically located between two camshafts on the valve cover and exposed to dirt and oil.
A failing points and condenser system can cause rough running, misfires, lean and rich conditions. If the engine is difficult to start, and runs rough once it does start, then it is time to contact a mechanic to have a look at the system and find out exactly what the problem is.
The relationship between crank and cam timing events can also cause no spark, especially on Chrysler products. On these vehicles, the PCM won`t trigger the ignition coil if the cam and crank are out-of-sync.
Although “diagnosable engine management systems” are installed in today`s vehicles, a multimeter or oscilloscope must be used when checking ignition systems.
If no spark appears, check for broken wires, shorts, grounds or a defective stop switch. Once you have confirmed that the stop switch is working, reconnect the spark plug lead.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Spark plug chaos. Rubber stoppers are preventing the spark plugs from coming out.
ANSWER : Hi there. Try using a pair of small needle nose pliers to pull off the rubber boots from the spark plugs. As you pull, twist the rubber boots to break them free. If you cannot get the rubber boots off, then try using some mineral oil on the boots to aid them off, then clean off the oil with soap and water with degreaser. If you need further assistance with removing the boots from the spark plugs, then seek out a professional, such as one from Your Mechanic, to help you.
Read Full Q/A … : After part replacements, spark plugs do not work
After part replacements, spark plugs do not work – 1996 Lexus LX450
ANSWER : If you have a Check Engine Light on, first check for those codes to determine what engine management thinks is going on. If no trouble code, check the ignition fuse behind the driver side kick panel (carpeted panel at foot level on the left – for left-hand drive vehicles). If the engine is spinning quickly, and doesn’t appear to be meeting any resistance (as a motor with good compression would have), you may have a broken timing belt. If so – STOP, call a professional mechanic, like a certified technician from YourMechanic for help.
Read Full Q/A … : After part replacements, spark plugs do not work
Engine will not stay started. I have replaced idle control valve map sensor spark plugs spark plug wires no check engine light is
ANSWER : You have a problem with the distributor assembly. I recommend replacing the distributor assembly. This will replace all the possible sensors and coil for the ignition and fix the problem you have.
Read Full Q/A … : After part replacements, spark plugs do not work
Just replaced head gasket, changed crack sensor new plugs. The check engine light is on, but dim, the only other light that the dash is a normal battery indicator. The fuel pump is not running when switch is turned on, the power windows don’t work, it turns over but not firing. It’s like only one part of the system is working. Also the heater fans work even if the switch is off.
ANSWER : I would first look at the diagnostic trouble codes. Those codes are available because the check engine light is on. If the fuel pump is not running (momentarily) at key on, that fault alone will prevent the car from starting as there will be no fuel pressure. Pump output and pressure can be directly tested and you can also check for electrical power to the pump. To find out why the engine will not run, the recommended diagnostic is a no start diagnostic. If you request that service, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Read Full Q/A … : After part replacements, spark plugs do not work
Need to replace bad spark plug & coil pack on Ford Expedition but not sure what else I need besides the plug and coil pack?
ANSWER : Hi There,
I would recommend having an expert from YourMechanic come to your location to take a look at the vehicle to first determine what the cause of the misfire is if this has not already been done. Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. When the misfire results from a fuel related issue, this is commonly related to a lean fuel condition (lack of sufficient fuel supply to the motor). Fuel related misfires can be caused by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air-flow sensor, a faulty or dirty idle air control valve or a vacuum or intake leak. When the fuel supplied to the combustion chamber is insufficient, this results in an ignition (spark) that is igniting a less than balanced load of fuel and air. This results in a misfire or an explosion in the cylinder that is much less powerful than the other cylinders. This creates a loss of power that resonates throughout the motor additionally causing other problems with ignition and fuel timing. Due to the number of different things that may cause an engine misfire, the quickest and easiest way to diagnose this type of problem is to hook the vehicle up to a scanning tool which will download any potential fault codes that may have registered in the vehicle’s computer as a result of the poor running condition. I would recommend having an expert from YourMechanic come to your location to diagnose your misfiring problem.
I would recommend having an expert from YourMechanic come to your location to take a look at the vehicle to first determine what the cause of the misfire is if this has not already been done. Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. When the misfire results from a fuel related issue, this is commonly related to a lean fuel condition (lack of sufficient fuel supply to the motor). Fuel related misfires can be caused by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air-flow sensor, a faulty or dirty idle air control valve or a vacuum or intake leak. When the fuel supplied to the combustion chamber is insufficient, this results in an ignition (spark) that is igniting a less than balanced load of fuel and air. This results in a misfire or an explosion in the cylinder that is much less powerful than the other cylinders. This creates a loss of power that resonates throughout the motor additionally causing other problems with ignition and fuel timing. Due to the number of different things that may cause an engine misfire, the quickest and easiest way to diagnose this type of problem is to hook the vehicle up to a scanning tool which will download any potential fault codes that may have registered in the vehicle’s computer as a result of the poor running condition. I would recommend having an expert from YourMechanic come to your location to diagnose your misfiring problem.
Read Full Q/A … : After part replacements, spark plugs do not work
Engine light fault. There was a bad spark plug and a failed ignition coil. Replaced both the coil pack or spark plug.
ANSWER : Hi there. If the light is coming on then shutting off and returning on, then if the issue is for the same coil, there could be an issue with the wiring on the coil plug. Check the wiring on the coil plug and see if the wires are split, broken, or burned. If there is nothing wrong with the plug, then the main engine harness has an issue / short and may need replaced. If you need further assistance with your ignition system, then seek out a professional, such as one from Your Mechanic, to help you.
Read Full Q/A … : After part replacements, spark plugs do not work
Just replaced spark plugs and wires and my car is still miss firing and I can’t pin point why and my old spark plug is oil covered
ANSWER : Hello there, many faults will cause your 1988 Ford Contour to have a misfire even after the spark plugs were replaced. When oil is seen on the spark plug this indicates that the valve cover is leaking onto the plugs. When this happens it fouls the plugs and can cause a misfire. Until the oil leak is addressed the spark plugs will continue to become fouled. If the misfire persists there are many potential causes such as the plug wires, fuel pump, vacuum leak, oxygen sensor, MAF sensor, or the cap & rotor. A qualified Technician such as one from YourMechanic will be able to diagnose your misfire fault and make any repairs required to resolve the issue.
Read Full Q/A … : After part replacements, spark plugs do not work
I have a dodge ram 1500 4.7- 2013 was changing spark plugs on top side with a 5mm socket socket is stuck help?
ANSWER : Hi there. Although what you are listing above is not necessarily a service we offer, it is possible to have one of our mobile mechanics come to your location to help you with this issue. To start, I would recommend setting up a spark plug removal service, then contacting the customer service sales professional that works with you to explain exactly what you need. When this has happened to me, I bite the bullet and purchase a new spark plug and new spark plug socket, as it’s very difficult to get it unstuck without damaging the socket.
Read Full Q/A … : After part replacements, spark plugs do not work
