What Causes Loose Spark Plugs

Spark Plug Problem Symptoms & When To Change It. The spark plug is the first thing you look at when a motor won’t start. Be sure the plugs do not drop into the plug wells as electrodes can be damaged. However, discoloration can increase with more racing mileage. You need to use a peak meter to read the millivolts being produced by both. In fact, there have been a small number of reports of engine fires due to spark plug ejection / blowout. The most likely cause would be the stator assembly. Are Bosch Spark Plugs pre-gapped at the factory? Most Bosch Spark Plugs are factory pre-gapped for popular vehicle applications. 2 engines use separate coil packs per cylinder instead of the DIS module, I felt that it should be supplemented by 2. How to Tell When it Is Time to Change the Spark Plug in a Lawnmower. It is recommended to use spark plugs with the special plating on all aluminum cylinder head applications to prevent damage to the cylinder head. Check the condition of your spark plugs and spark plug wires. A bad spark plug also may cause misfires, with the engine sputtering, missing or popping. How to Diagnose a No-Spark or Loss of Power Condition on a Modern Car Misfires caused by a loss of power condition on a car can be tricky to diagnose, but are necessary to fix to avoid further damage and costly repairs. and can cause flashover resulting in misfires. The result is a misfire in the spark plugs. By disconnecting the cannon plug for the. In addition to causing your check engine light to turn on, a bad O2 sensor will have a negative impact on fuel economy, spark plugs or your catalytic converter. If they're too loose, you may be able to turn it with your fingers. A vehicle experiencing a knock should be quickly inspected to avoid any serious damage to the internal components of the engine. NOTE: AVOID OVER TIGHTENING OR UNDER TIGHTENING AS SPARK PLUG OR ENGINE DAMAGE MAY RESULT. The structure of the ash is loose to cinder-like. What to Do. The problem was obvious once the plastic silver cover over the spark plug wells was removed, as the #2 spark plug wire's boot was sitting about 3/16" off the top of the valve cover surface, instead of being perfectly flush like the other 3 cylinder's wires. - vacuum leaks. The information here relates to spark plugs manufactured by NGK which are suitable for Vespas and Lambrettas. For gasoline fuels, the residuals of carbon compounds from rich mixtures of gasoline fuels can cause discoloration. This is a common problem after DIY tune-ups. I have had the IAICH (idle circuit) valve go out and when it does it fouls all the plugs to the point they are junk. As the number of misfires per mile goes up, exhaust emissions are increased and gas and power are wasted. Every time a spark plug fires, the spark burns a few molecules of metal off the plug’s electrodes. Learn how to change spark plugs on Mazda. CDI unit faulty. loose spark plug Post by guillermo848 » Mon Jun 13, 2011 6:33 pm my truck is a 1994 f150 5. Warning Signs of a Bad Spark Plug. If the spark plugs are old you might try new ones. If you loose spark on both plugs it could be a faulty trigger coil, or stator. 025" and the blade slides through the gap quite easily, without being too loose. Remedy: Repair engine. How to Change Spark Plug Wires. I get a weak spark and spark knock when I drink light beer! Seriously, you could just have a loose ground on the coil. What would cause no spark at the spark plugs on a mercury 125 outboard? Answer. Probably, you would be able to save some money on auto repair. You'll need it, and I'll sell it cheap. Care must be taken during installation that the spark plug socket is not slanted and does not slip causing insulator breakage (See Figure 1). The most likely cause would be the stator assembly. I went with the E3. From NGK - For spark plugs with special metal plating; anti-seize is not recommended during installation. Possible Causes: Depending on whether the spark plug is coated in oil or fuel, wet fouling can be symptomatic of a compromised head gasket, poor control from your pistons’ oil control ring, valvetrain problems, or an extremely rich condition. A wider gap may result in misfiring due to the voltage not being quite high enough to cause a spark across the electrodes. In fact, there have been a small number of reports of engine fires due to spark plug ejection / blowout. If you want to experiment a bit with Spark Plugs, how about going for the so called fan flame Spark Plugs. What's New 3 12 24 72. Clamp the square drive horizontally in the vise and hang a 15 lb dumbell from the handle, 12" from the pivot. I checked the spark plugs and noticed that one of them was loose and had some oil in it. Conditions that also contribute to pinging and pre-ignition Wrong or gimmick spark plugs. I now own a Ford 4. In general, copper spark plugs require replacement every 20,000 miles. Internal damage can still occur without the insulator actually breaking. Consider the tremendous pressure that your engine produces in each cylinder. Search My Stuff. 7 shows the opposite kind of problem. One common cause of a check engine marker light-up is spark plug wires gone bad. If your engine has a coil-on-plug ignition system, replacing the rubber boot that fits between the coil and spark plug is recommended when changing high mileage spark plugs. Shocking them loose with a quick burst from a strong impact will remove them handily. This can cause a catalytic converter to be damaged, and in severe cases can cause a fire when. For example, spark plugs and spark plug wires, but the ignition coil and ignition timing should be checked as well. Can a faulty stator cause plugs to die quickly? jetting, reeds, coil and fuel mixture are all fine, but spark plugs loose all spark after about an hours riding, and suggestions are appreciated. If the spark plug wires or ignition coil(s) are bad, the plugs won't fire the air/fuel mixture. This causes some issues like: Carbon buildup; Erosion of the ground electrode; Worn or loose spark plug cables; In this guide, you’ll learn how to inspect your spark plugs and tell a bad one from a good one. Spark plugs gapped correctly? For what it's worth, you might check the gap but don't try to change the gap, as you stand a high chance of damaging the electrode on the plug itself. Cause: Alloying constituents, particularly from engine oil, Bosch Spark Plugs 0307 Spark Plug Faces — Part 3. White smoke after changing spark plugs? I changed my spark plugs on my 1990 300zx and now white smoke comes out the back and if i rev the car it has a really hard time staying on but it does stay on when i dont rev it. This guide was designed to assist the technician, hobbyist, or race mechanic in understanding, using, and troubleshooting spark plugs. It is plausible that the loose plugs were causing a tapping noise as gases are being forced past during combustion. Follow the recommended maintenance schedule. It is well worth buying long life plugs to attempt to double the time between plug changes and inlet manifold removal. A spark plug that is too loose will not have good heat transfer and may allow the plug to overheat. Labour tends to be rather more expensive than a few extra ponds spent on higher lifed plugs. This is often caused by piston rings or cylinder walls that are badly worn. As shown in the Crank/No Start video, you can easily check for spark with a spark tester or screwdriver. The best way to determine when spark plug replacement is needed is the maintenance schedule for your specific vehicle. The procedure is very clear and the pictures are just fabulous. One cause could be an engine that has had the cylinders been bored oversize. Always tighten spark plugs to the specified torque. Do I need colder spark plugs? Will colder spark plugs give me more power? These are common questions and they unfortunately get answered incorrectly most of the time or incite a flame war. This problem can be caused by too much oil in the fuel and oil mixture and/or having a faulty spark plug that is misfiring. The increase in electrode gap will be considerably in excess of 0. Polaris jet-ski has no spark, weak spark or intermittent spark refers to when an electrical discharge occurs at irregular intervals or lacks the ability to ignite the explosive mixture in the watercraft's internal combustion engine, and subsequently, the motor fails to start up. Tighten or connect where necessary. Ignition problems can also cause wet spark plugs. Most vehicles sold in the United States require their spark plugs to be replaced every 20,000 to 50,000 miles. To replace the Spark Plugs: Insert a 6-8” extension onto the 5/8” spark plug socket and then insert into the open crankcase. After prolonged use, the spark plug tip can become coated with ash, oil, and other residue. Loose fitting boots or damaged cables can cause ignition misfire. These may have been included with a pulley upgrade. I checked the oil and now it showed the level to be well above the top mark on the dipstick. NGK Spark Plugs have a FAQ page that answers many of the spark plug questions. I hope my situation may help someone else out. Cause: Alloying constituents, particularly from oil, may deposit such ash in the combustion chamber and on the spark-plug face. The idea is to impress on consumers the spark plugs can last the life of the car. Cold (carbon) fouling of the entire set of spark plugs may be caused by a clogged air cleaner element or repeated short operating times (short trips). I've just replaced cap and rotor, spark plugs, O2 sensors, and catalytic converter. Figure 1: This spark plug was over-torqued. Air/fuel mixture incorrect: Idle air screw mis-set. Causes hard starting in damp or cold weather and poor fuel economy. ) Handling: Remove all the spark plugs, crank the starter motor to bring fresh air into the cylinder and make the air-fuel ratio leaner. With help from the spark plug experts at NGK, we'll teach you how to diagnose minor tuning issues or potentially major engine problems by examining your spark plugs. The health of the spark plug is linked to the performance of the engine and as shown in the image above, they can become damaged easily. If a spark plug is loose, major problems can insue. 4 Reasons Why Engines Lose Power Over Time And How To Win Your Horses Back. It really doesn't back out enough to really cause a compression problem but enough to make a saw not idle quite right or an acceleration problem or if you have an ear for ignition it can make it sound or feel like it. If the fuel in your engine is old, it should be properly disposed of and replaced with fresh fuel. If your spark plug is black or oily than that means the engine is running too rich and is not properly combusting fuel. Install the New Valve Cover Gasket. Most people run into this issue when they attempt to replace the spark plugs on their Chevrolet Spark and Cruze models. Causing more likely hood of arcing. Good spark plugs will burn fuel efficiently, while bad or failing spark plugs can cause the motor not to start at all. 025" and the blade slides through the gap quite easily, without being too loose. Our recommendation is to use the ratchet only to make the spark plug loose and then remove it. for an additional $150. NGK have over 80 years of experience in spark plug manufacturing and we are a world leader in spark plug technology. An under-torqued spark plug can also work loose and fall out of the engine. Good spark plugs will burn fuel efficiently, while bad or failing spark plugs can cause the motor not to start at all. 6 signs your spark plugs need to be replaced If you're having trouble starting your car, it may be due problems with your spark plugs or ignition wires. Brisk spark plugs rival those of NGK and offer great gains in off idle throttle response as well and come in at right around $80. Bad or broken wires can also cause misfires. The fuel air mixture inside of the cylinder can build up and cause a back up. Smaller gaps, or smaller electrode tips (like found on platinum- and iridium-tipped plugs), require less energy to spark. Clean if needed. Here's the five things you should know about them. There are two basic types used on classic Italian scooters. After every 10,000 miles, motoring experts advise that the spark plugs need to be supervised as they can stop functioning. If loose , adjust them back and the misfiring will cease. As far as pinging, detonation, and pre-ignition are concerned, typically they occur under load and pretty much never at idle. 4 Reasons Why Engines Lose Power Over Time And How To Win Your Horses Back. Engine Misses Under Load Faulty spark plug. RAY: Then, as the engine ran and vibrated, the plug slowly unscrewed itself. Maybe not always easy, but definitely straightforward. ) Handling: Remove all the spark plugs, crank the starter motor to bring fresh air into the cylinder and make the air-fuel ratio leaner. It’s because the conditions within the combustion chambers (where the spark plugs are located) are extremely harsh. When I was doing this, I noticed that one of my spark plug wires had popped off of the spark plug. Could too much oil cause the spark plug to get dirty, get loose and misfire?. RAY: It sure sounds like one of your spark plugs popped out. Wiki User 04/20/2008. Spark plug gap:0. I tightened that plug back down then used the sea foam through the vacuum hose into the engine, some in the crankcase (not while it was running though) and the last third into the fuel. Every time a spark plug fires, the spark burns a few molecules of metal off the plug’s electrodes. Numerous questions have surfaced over the years, leaving many people confused. An engine knock results from one of several problems such as a loose connecting-rod bearing, bad fuel mixture, worn spark plugs or carbon build up inside the cylinder walls. Clean if needed. Once your spark plugs start to wear out, your car's performance and fuel economy will suffer, and your engine can begin to run or idle rough as well as use more fuel. One of the most common causes of an engine misfire condition is the tune up parts. Cause: Overheating caused by auto-ignition, for instance the ignition being too far advanced, combustion deposits in the combustion chamber, defective ignition distributor, or poor-quality fuel. Will bad spark plugs cause my car not too start? my car is giving me a hard time starting and i wanted too know if its my spark plugs because i was told by a machanic 5 months ago that they needed to be repaired and i heard ticking noise from my car, will back spark plugs give your car a hard time too start?? i have a 2000 chrystler 300m btw. Jeff Buckley of My Fathers Shop explains how an ordinary Tuneup can turn into additional repairs caused by the valve cover gasket leaking oil into the spark plug tube. Also, running a loose enough spark plug for any period of time can cause serious damage to your top end (piston/cylinder and related components). Basically, these seals are the major cause of oil on spark plug threads, which allowed the oil to seep into the spark plug. The reason I ask is because they seem to break loose and come out pretty easy. Spark plugs fire when you accelerate and change gears. 8pcs NGK 6668 V-Power LFR6A PWC Spark Plug Tune Up Kit Set pe Status: In Stock Condition: New. 32 and one was all the way to. The worst case scenario is pieces of the broken spark plug such as the platinum tip electrode and ceramic fragments can fall down into the cylinder. The Bosch book "Gasoline Engine Management" has good information on troubleshooting spark plugs by appearance. A bad spark plug also may cause misfires, with the engine sputtering, missing or popping. To avoid the problem, replace spark plugs on older cars every 25,000 to 35,000 miles. I recommend using a torque wrench for fastening spark plugs. Clean the ground from the battery and ignition coil. k This is often caused by over advanced ignition, timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean air/fuel mixture, or a leaking intake manifold. A flat slap, when advancing engine speed under load, indicates a loose piston: Replace piston. How to check or change the engine spark plugs in a third generation Kia Sportage with the Theta II 2. Good spark plugs will burn fuel efficiently, while bad or failing spark plugs can cause the motor not to start at all. As voltage builds at the electrode, atoms in the air within the air gap gain electrons. I checked my spark plugs today and checked the gap, some were at. I Wiped out most the oil and finished replacing the plugs. 025" and the blade slides through the gap quite easily, without being too loose. "Excessive torque damages spark plug seal. If your spark plug is black or oily than that means the engine is running too rich and is not properly combusting fuel. Spark plug heat range is also affected by coolant temperatures. It’s cheap insurance. Failure to route the cables properly can cause the radio to reproduce ignition noise, cross ignition of the spark plugs or short circuit the cables to ground. Figure 1: This spark plug was over-torqued. Idle problems may originate in a worn out component, a. Under-torquing is a "don't" because a loose or improperly seated spark plug can overheat which can cause a pre-ignition or a misfire condition. If the plug wont fire under compression what would be the reason for that? #. Spark Plugs and Gasoline Fuels. Since there is a leak, the coolant is not able to circulate well throughout the system. Re: 2001 Ficht 175. First if you do change your spark plugs use only NGK or Denso Iridium which are the recommended spark plugs. If a plug wasn't tightened properly when it was replaced, it could have just loosened up over time until it finally popped out. Spark plugs with tapered seats should be tightened an additional 15°. Spark plug wires and ignition coils tend to last a little longer, but usually no more than double the lifespan of the spark plugs they power. 1 lb-ft of torque over the coppers! Conclusion: Swapping spark plugs can increase power output if the OE-recommended plugs can't ignite air and fuel at maximum efficiency. These can cause random misfire conditions. I changed spark plugs, fuel filter, and oil. First if you do change your spark plugs use only NGK or Denso Iridium which are the recommended spark plugs. Note the brown to greyish tan color,. Here's my question: My bike is eight years old and the plugs in there now have never been removed. Internal damage can still occur without the insulator actually breaking. Spark plug cap not in good contact with spark plug. In general, copper spark plugs require replacement every 20,000 miles. The poor con - nection forms ozone which builds up on the walls. Dispelling The Spark Plug Myths. The second cause is loose shifting linkage itself, which connects the gear. This can cause pre-ignition or "spark knock". Speaking of spark plugs, worn or fouled plugs can cause a variety of issues including an engine misfire. The result is that the spark plugs are more likely to blow out after you attempt to start the engine once again. In general, copper spark plugs require replacement every 20,000 miles. When removing the spark plugs from your vehicle, it's important to remember to set up your station properly and take the necessary safety measures. If you smell exhaust from the engine compartment and hear a ticking noise, you have a leak. 0 TFSI spark plug replacement, common to the A4, A5 and Q5 models. I had one vibrate loose, less than half a turn, but enough to make the cylinder lose spark/compression and cause the motor to run rough. They also have Time-serts instead of helicoils. It is also possible that you have a leak somewhere in the engine cooling system. Re-fitting the spark plugs. I use mine every time I remove the wires. If you’re in the market for a new or used spark plug, check out our spark plug buying guide today to determine the best product for your engine. However, today, car was running a little strange, I pop the hood, same plug wire, off of the spark plug. The best way to sidestep the Chevy Cruze ignition coil problem is to not touch it. 2 specific info. Good luck and keep us updated. Or, if you’ve left a tool on top of the intake or valve cover it can cause a rattling sound. Possible Causes: Depending on whether the spark plug is coated in oil or fuel, wet fouling can be symptomatic of a compromised head gasket, poor control from your pistons’ oil control ring, valvetrain problems, or an extremely rich condition. Use a spark. Spark plugs are actually quite long lived. Indexing plugs can only be achieved when a conventional-type “gapped” plug is the threaded into the head. Air/fuel mixture incorrect: Idle air screw mis-set. Install the New Valve Cover Gasket. Screwed the plug back in properly, and the noise is gone. Possibly the silliest reason that your check engine light is on, a loose, damaged or missing gas cap may cause your check engine light to come on. WELL! Decided to check the ol spark plugs. To answer the other part of your question lean jetting can absolutely cause detonation. Use FIXD to scan your vehicle to verify P0300 is the only code present. If the spark plug wires or ignition coil(s) are bad, the plugs won't fire the air/fuel mixture. Loose plugs might cause misfiring if they leak badly and cause low compression, but they won't make the mixture lean. if its really loose, then the fuel air mix can escape into the combustion chamber. Loss of spark includes anything that prevents coil voltage from jumping the electrode gap at the end of the spark plug. The aluminum head cools and therefore shrink s faster than the steel plugs. Discussion about the “right” way to check spark plug resistance can go on until the cows come home. " Carbon tracking causes spark plug misfires. The procedure is very clear and the pictures are just fabulous. Clean if needed. Can result from: inoperative exhaust gas re-circulation system, defective detonation sensor, lean air fuel mix, incorrect fuel octane rating or spark advance and loose fitted spark plugs; Effect: Misfire and/or general poor/ uneven running which may result in engine damage; Remedy: Identify the cause and replace the spark plugs. If your spark plug is black or oily than that means the engine is running too rich and is not properly combusting fuel. This is only valid if you shut-off the engine after the finish line then tow the car back to the pits where you remove the plugs for reading !!. If you’re in the market for a new or used spark plug, check out our spark plug buying guide today to determine the best product for your engine. They make special helicoils for spark plugs. To avoid the problem, replace spark plugs on older cars every 25,000 to 35,000 miles. If loose , adjust them back and the misfiring will cease. Running too cold a plug can only cause it to foul out, whereas running too hot a plug can cause severe engine damage. What causes a spark plug to blow out of the threaded hole, stripping it in the process and denting the hood? That is normally caused by a loose spark plug. Regardless, exactly this happened to some 5. If you ignore this it can cause engine damage. Stop if you find that the spark plugs are sitting so tight in their holes that you can't wrench them out. Conventional fault tracing involve basic checks such as vacuum leaks, bad fuel, wiring faults, and worn or fouled spark plugs, loose alternator belt or faulty alternator. k This is often caused by over advanced ignition, timing, poor engine cooling system efficiency (scale, stoppages, low level), a very lean air/fuel mixture, or a leaking intake manifold. 2 engines use separate coil packs per cylinder instead of the DIS module, I felt that it should be supplemented by 2. Engine oil viscosity not correct. I hope my situation may help someone else out. Why does the Engine of my Car Shake?. Hard to say if its just at idle or not as you can't smell it on the go as it will just get absorbed in the air whilst on the move, but it is there when idle. The second cause is loose shifting linkage itself, which connects the gear. You should also crank the engine and check that the distributor is turning. Remember that before you remove the old seals and valve gasket, you have the new ones, in hand. The difficulty of removing, checking, and installing spark plugs varies with different engine brands and. Several components in the system need service at regular intervals. Bosch Platinum Plus spark plugs: Made with durable, efficient platinum, these plugs maximize MPGs. Check for loose connectors at the ignition coils or for damaged wiring. Just so we're clear, what we are looking at. It is recommended to use spark plugs with the special plating on all aluminum cylinder head applications to prevent damage to the cylinder head. The fuel air mixture inside of the cylinder can build up and cause a back up. Overlooking these basics can lead to breakage issues during the next replacement. if your burn ring on your plug is. I used Danuk excellent How2 for the 3. As a result, broken pieces or fragments of the defective spark plugs get stuck in the cylinder. The factory recommended torque is too low and causes the plugs to back out and blow out of the head. Next morning I started the car and right away notice that the engine was misfiring. It is very important to properly tighten spark plugs during installation. If the plug is loose, it will strip out go flying at a high rate of speed. Search My Stuff. Also a sensor to the throttle body may be bad. Cooling fins plugged. Spark plugs indicate lean mix on carbureted V6. I put it back on and didnt think much of it. I installed plugs and wires about 2k miles ago. There are tons of different types of spark plugs (iridium, platinum, standard, pre-gapped, 4 grounded etc. Bad or broken wires can also cause misfires. Do a google search on taking spark plugs out of a warm engine. So when to replace spark plugs? It depends on the type of spark plug and materials it is made from. How to Repair Stripped Spark Plug Threads: Auto Clinic Spark plugs that haven't been changed for a long time can become one with the cylinder head. RAY: Then, as the engine ran and vibrated, the plug slowly unscrewed itself. A wider gap may result in misfiring due to the voltage not being quite high enough to cause a spark across the electrodes. im going to chuck a set of these on my V8s and see how they go. If you consider your spark plugs little more than disposable engine parts to be replaced for every event or two. But you are right with regular Zink paste. Loose spark plugs almost got me tonight! I had a chirping noise coming from the throttle body rubbing just a little on one of the black mounts next to the valve cover, and thought I solved the mystery. Good spark plugs will burn fuel efficiently, while bad or failing spark plugs can cause the motor not to start at all. when i slowly reved the. E-250 VAN 5. Several components in the system need service at regular intervals. White smoke after changing spark plugs? I changed my spark plugs on my 1990 300zx and now white smoke comes out the back and if i rev the car it has a really hard time staying on but it does stay on when i dont rev it. Spark plugs get worn out with time due to spark plug fires that burns a few metal molecules of plug electrodes during ignition. Confusion can set in when it is time to put these spark plugs back into their slots. 4 Triton engines right from the start in 1997. In fact, with a crank/no start condition, I often check for spark first since it's usually the easiest thing to check. Determine if ignition timing is over advanced or if other operating conditions are causing engine overheating. the ones i used were ngk BKR6. The deposits that cause cold fouling are basically carbon. Drove home without an issue. Greco Tire & Auto is the leading 150,000 mile service shop in Danbury, CT, Ridgefield, CT, and Bethel, CT. The spark plugs simply supply spark to the cylinder. If its milidly, loose, the electric arc at the end of the plug, will not be in proper placement to properly ignite the mixture. Look for loose engine ground wires as well. The poor con - nection forms ozone which builds up on the walls. A loose spark plug can. Car has almost 88,000 miles on the odometer. One cause could be an engine that has had the cylinders been bored oversize. The best way to determine when spark plug replacement is needed is the maintenance schedule for your specific vehicle. Re: MINI Cooper Spark plug popped out Car is a 2003 MINI, base model. A bad spark plug also may cause misfires, with the engine sputtering, missing or popping. Coat threads of spark plug with anti-seize. That does dry out and might become very sticky in a cylinder head. It can be very understandable why car owners will ignore the spark plugs. The pin at fault can be found by short circuiting the spark plugs, one at a time, until the noise stops: Repair or replace. Find out how to inspect your plugs and wires to ensure that your ignition coil is delivering adequate spark. Car Care: Take cars that misfire regularly to a repair shop, where mechanics should check for bad spark plugs or an ignition boot failure. If gasket style spark plug is installed without sealing gasket,. I put in a new battery, points, plugs, condensor, rotor, dizzy cap, leads, and coil. Higher That Normal Compression. The rotor is up against the center dizzy cap terminal, points were opened and spark was seen jumping from the rotor to one of the dizzy's terminals. If the fuel in your engine is old, it should be properly disposed of and replaced with fresh fuel. First, you should figure out if the spark plug is the problem. TOM: Sometimes, spark plugs just work their way out over time. Deteriorated Spark Plug or Spark Plug Wires. Spark plug gap:0. If loose , adjust them back and the misfiring will cease. Spark Plugs and Ignition Performance. Common Causes of Mercedes Engine Misfire Spark Plugs. NORMAL Combustion deposits are slight and not heavy enough to cause any detrimental effect on engine performance. new spark plug used spark plug Sealing with a gasket (washer) - spark plugs can never be mounted into cylinder head without a sealing gasket (washer).