0000072229 00000 n Spark plug problems can arise from a variety of things. 190 175 0000075419 00000 n 0000000016 00000 n It causes missing or roughness and creates soft black soot that is easily removed. 0000072524 00000 n 0000074855 00000 n 0000040001 00000 n 0000123754 00000 n 18 160 0000006710 00000 n 0000130638 00000 n 0000017313 00000 n Normal. 0000049673 00000 n 0000139471 00000 n 0000020561 00000 n 0000003873 00000 n 18 0 obj <> endobj 0000123611 00000 n 0000064466 00000 n 0000025705 00000 n 0000132193 00000 n 0000124376 00000 n Tis the season for tune-ups, my friends! This may lead to pre-ignition/detonation and expensive engine damage. 0000009178 00000 n Carbon fouling is caused from low-speed operation or a fuel mixture that is too rich. 0000123184 00000 n 0000039455 00000 n 0000125599 00000 n 0000006343 00000 n Carbon fouling often occurs when your vehicle’s engine is running too rich. 0000034568 00000 n 0000121650 00000 n 0000050136 00000 n 0000122912 00000 n 0000074661 00000 n 0000246116 00000 n If the gauge can’t fit between the center and side electrodes, the gap is too small, which means that the spark plug isn’t burning the fuel/air mixture efficiently. 0000004192 00000 n 0000050703 00000 n Dry and wet fouling. 0000121791 00000 n 0000075341 00000 n 0000027987 00000 n 0000028123 00000 n 0000042654 00000 n 0000034418 00000 n 0000124822 00000 n The partially solid compounds liquefy when you put a high torque load on the engine. 0000040414 00000 n H���KoS1�����:���B�@�kT� 0000304258 00000 n 0000011920 00000 n 0000124971 00000 n Sometimes a good spark plug will just go bad. 364 0 obj <>stream 0000030367 00000 n 0000006187 00000 n 0000128461 00000 n 0000126135 00000 n Oil fouling of a spark plug typically results in a shiny, black appearance. 0000064071 00000 n Spark Plugs Usually Die a Slow Death. Problems here can allow oil to dribble down the valve stems and enter the combustion chamber. 0000006878 00000 n A bad spark plug may cause your engine to sound rough while idling. 0000123047 00000 n 0000129033 00000 n 0 0000424715 00000 n Normal colour. If the tip temperature is higher than 850°C the spark plug will overheat which may cause the ceramic around the centre electrode to blister and the electrodes to melt. xref A clean, white insulator firing tip and/or excessive electrode erosion indicates this spark plug condition. xref 0000027651 00000 n 0000017600 00000 n Plug has been in there too long. 0000130018 00000 n Spark plugs can be the “canary in the coal mine” for underlying engine issues. 0000006962 00000 n 0000038577 00000 n 0000043615 00000 n 0000040200 00000 n 0000126853 00000 n 0000017183 00000 n 0000041855 00000 n 0000128173 00000 n 0000016825 00000 n 0000043231 00000 n 0000130256 00000 n Possibly precipitation of material not originating from the spark plug. 0000039103 00000 n 0000027854 00000 n The electrode wear is uniform and like the threads, should appear free of oil and unburned carbon. 0000006668 00000 n Discussion on possible causes of and solutions to a fouled spark-plug. 0000064411 00000 n 0000006836 00000 n Since they are continuously in use while an engine is running, they have a natural shelf life and can wear out. 0000005964 00000 n 0000064328 00000 n To remove heat from the combustion chamber. 0000035318 00000 n 0000124725 00000 n If the selected spark plug heat range is too cold, the spark plug may begin to foul when the engine speed is low or when operating in cold conditions with rich air-fuel mixtures. 0000028952 00000 n 0000003496 00000 n What to Look For 0000124227 00000 n You’ll need to fix this problem quickly before the engine is affected too much. 0000036243 00000 n Dark coloring, such as heavy black wet or dry deposits can indicate an overly-rich condition; too cold a heat range spark plug; a possible vacuum leak, low compression; overly retarded timing or too large a plug gap. 0000025559 00000 n 0000035123 00000 n Close scrutiny of the firing end can also suggest a variety of possible engine conditions and point the way to achieving improved spark plug and engine performance. 0000073088 00000 n 0000031849 00000 n 0000006416 00000 n A normal spark plug will have brown or grayish-tan deposits on the side electrode. A carbon-fouled plug will have black, dry soot on the electrodes and insulator tip. When these conditions prevail, even … 0000037022 00000 n 0000042854 00000 n The controlled explosion of the fuel-air mixture no longer occurs at the precise moment in the four-stroke cycle. Images 5 & 6: The wet, shiny deposits shown on these spark plugs are oil. 0000006552 00000 n 0000035882 00000 n 0000025876 00000 n 0000008638 00000 n 0000050787 00000 n 0000074213 00000 n 0000010183 00000 n 0000030536 00000 n Rough Idle. %PDF-1.4 %���� 0000123327 00000 n 0 trailer 4) Bad Piston How the Spark Plug Works . A black, dry soot may develop on … startxref Over time, the spark plugs in a healthy engine develop a slight brown or tan tint of color on the center and ground electrodes. hÞb``°g`(b`g`= Ȁ ‚¬l,7v…500|;À€8ª\íI½‘ò\¶ò‡b—¥ê pdt€ DaZ˜Ó 6 ¬†b5VQ YÇàÃàÅ`͐#“(Y%¹B¢A2Cª—ч1ˆIˆñ8ƒc ãNCƕL‚zŒ*Œ‘ÜGn3èݬ ԕÏiÉ[ÍÚÍ`Îà͐4UƒQ(ã‡D¡ña´0ˆf>ÀÈÎh´:Ÿ‘!!3€ÄNaHbHdHfȋd2nfÈg4ّ`2L:3¸Cñd†r ®t†` h2XB¦u¥Åó-1t'I †W@üˆßAÙoA4û1öcœ×;€iã¯ÁtèÉ¥ š£þT$û/ö_œôÀ⹗÷0H0à¼â Ø`b`à6‚‹º0ðšòiF Þ ` šùe 0000129481 00000 n 0000026658 00000 n 0000033867 00000 n 0000073481 00000 n 0000075903 00000 n 0000127145 00000 n 0000478957 00000 n Running too rich means there is too much fuel in the air/fuel mixture when it is ignited by the spark plug. 0000016612 00000 n 0000004650 00000 n 0000017248 00000 n 0000016538 00000 n 0000038920 00000 n 0000038053 00000 n Tags: NGK , reading your spark plugs , Spark Plugs 0000017535 00000 n 0000006065 00000 n The excessive quantity of oil can result from worn cylinders, piston rings or valves. 0000075787 00000 n 0000132546 00000 n 0000127790 00000 n If enough oil is in the combustion chamber, the deposits can build up on the tip, porcelain or shell. <<25d09b8a0cde5f47b0004ea3112f59f8>]>> Severely eroded or worn electrodes. 0000122497 00000 n 0000038399 00000 n 0000127407 00000 n 0000003933 00000 n Cause: Incorrect mixture setting (carburetor fuel injection); mixture too rich, air filter very dirty, automatic choke not in order or manual choke pulled too long, mainly short-distance driving, … 0000128884 00000 n 0000129630 00000 n 0000132271 00000 n 0000121510 00000 n 0000127286 00000 n When this happens one cylinder will stop working. 0000036633 00000 n 6. 0000306471 00000 n 0000362470 00000 n 0000006584 00000 n 0000130159 00000 n 0000027455 00000 n 0000034973 00000 n 0000037553 00000 n 0000006626 00000 n 0000025383 00000 n 0000039630 00000 n 0000017047 00000 n 0000248543 00000 n 0000242060 00000 n 0000029627 00000 n 0000131137 00000 n All of a sudden a spark plug will just stop producing a spark. 0000040838 00000 n 0000032777 00000 n 0000132624 00000 n 0000072486 00000 n There are three basic types of spark plug fouling: "carbon" fouling, "high speed" or "lead" fouling, and "oil/carbon" fouling. 0000072342 00000 n 0000034770 00000 n 0000005888 00000 n 0000043043 00000 n Spark plugs which have exceeded their recommended service interval and have expanded gaps, may also contribute to misfires. 0000006455 00000 n 0000032597 00000 n 0000024698 00000 n 0000131215 00000 n 0000031267 00000 n 0000073652 00000 n 0000006920 00000 n Normal spark plug. startxref Common reasons for Oil leaking into spark plug well: Leaking Valve Cover Gaskets: The valve cover is a metal part found on the top of the engine, which seals the engine and helps prevent oil leaks. 0000128604 00000 n It occurs because of excessive compression and heat in the combustion chamber. 0000125360 00000 n 0000016751 00000 n In general, a light tan/gray color tells you that the spark plug is operating at optimum temperature and that the engine is in good condition. Standard Spark Plug Conditions: An examination of used spark plugs can reflect the accuracy of heat range application. 0000131921 00000 n 0000037900 00000 n 0000028748 00000 n 0000072136 00000 n Spark Plug Trouble Tracer. 190 0 obj <> endobj 0000033139 00000 n 0000244088 00000 n If you can’t determine if it is carbon or oil fouling, smell the plug; it will smell like engine oil. 0000006229 00000 n 0000024865 00000 n Spark plugs are a popular item to change, and it is important to know what a good spark plug vs. a bad one looks like.There are tons of different types of spark plugs (iridium, platinum, standard, pre-gapped, 4 grounded etc.,) but there still are some telltale visual signs that tell you of a bad spark plug (or a poorly running cylinder). 0000040019 00000 n 0000038216 00000 n 0000073166 00000 n 0000036835 00000 n Easily identify the problem with our Trouble Tracer! 0000121932 00000 n 0000032417 00000 n Between the valve cover and the engine are gaskets that tend to fail over time. 0000129384 00000 n 0000121471 00000 n endstream endobj 191 0 obj <>/Metadata 67 0 R/Pages 66 0 R/StructTreeRoot 69 0 R/Type/Catalog/ViewerPreferences<>>> endobj 192 0 obj <. 0000026076 00000 n 0000049586 00000 n 0000042456 00000 n 0000064642 00000 n 0000007004 00000 n Fuel system problems may cause a rich or lean condition, which can contribute to spark plug misfires. 0000017112 00000 n 0000046854 00000 n %PDF-1.4 %âãÏÓ 0000026856 00000 n 0000035675 00000 n Known as engine spark knock, this phenomenon describes a very erratic form of combustion. And since the oil saturates the spark plugs, you’ll need to replace the spark plugs as well. 0000017458 00000 n The spark plug has two primary functions: To ignite the air/fuel mixture. 0000028605 00000 n 0000006500 00000 n 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. 0000073730 00000 n 0000025032 00000 n hÞbbr``b``Ń3Î¥¶™ ¦J 0000125211 00000 n 0000043429 00000 n 0000064791 00000 n 0000010614 00000 n %%EOF Gap bridging is a consequence of deposits collecting in the combustion chamber. 0000009636 00000 n This electrical spark ignites the gasoline/air mixture in the combustion chamber. 0000048733 00000 n 0000049107 00000 n Causes of carbon fouling include rich fuel mixture, clogged air filter, prolonged low-speed driving or idling, faulty ignition system, retarded ignition timing and spark plug heat rating is too cold. 0000010375 00000 n 0000041452 00000 n Causes of Spark Plug Problems. 0000029826 00000 n 0000129869 00000 n 0000027060 00000 n 0000006542 00000 n 0000075170 00000 n 0000123469 00000 n Caused by over advanced ignition timing; poor engine cooling system, lean air fuel mixture, or a leaking intake manifold. 0000130865 00000 n 0000420236 00000 n 0000029259 00000 n 0000051117 00000 n 0000130541 00000 n 0000070679 00000 n 0000039277 00000 n 0000364876 00000 n 0000136952 00000 n But certain conditions can cause them to wear out faster than usual or to go bad very quickly. 0000134924 00000 n 0000027167 00000 n 0000040624 00000 n 0000128076 00000 n Compare the state of your spark plug with the table below to diagnose any problems. Some common causes of spark plug fouling include: Worn or damaged valve guides or valve guide seals. 0000130405 00000 n 0000072972 00000 n 0000033520 00000 n 0000126240 00000 n So, a clean, white insulator firing tip and or excessive electrode erosion; indicates this spark plug condition. 0000016683 00000 n 0000127010 00000 n 0000006458 00000 n 0000127556 00000 n 0000048661 00000 n 0000047224 00000 n 0000300202 00000 n 0000011108 00000 n 0000122776 00000 n Fouling, either dry (top - matt black, sooty) or wet (bottom - gloss black, sticky), Can be caused by many different conditions. 0000007938 00000 n 0000029468 00000 n Replace with new plugs of the same heat range. The newly liquefied material then collects and solidifies between the electrodes of the spark plug. Spark plug conditions Normal Carbon-fouled Oil-fouled Severe centre electrode wear ... conductive and causes misfiring. 0000012859 00000 n 0000184373 00000 n 0000043802 00000 n 0000077202 00000 n 0000074777 00000 n 0000190843 00000 n 0000006794 00000 n 0000030708 00000 n 0000122073 00000 n 0000026264 00000 n endstream endobj 363 0 obj <>/Filter/FlateDecode/Index[69 121]/Length 27/Size 190/Type/XRef/W[1 1 1]>>stream 0000130787 00000 n 0000358310 00000 n 0000037734 00000 n To remedy this situation, make appropriate mixture adjustments, replace air filter or use a hotter spark plug in case of extreme stop & go driving conditions. %%EOF 0000017381 00000 n 0000037216 00000 n 0000126454 00000 n A good indicator that the plug is functioning correctly and general engine conditions are good. 0000033717 00000 n 0000007089 00000 n 0000041651 00000 n 0000036032 00000 n Carbon deposits build up when the plug … 0000128322 00000 n 0000042252 00000 n 0000129772 00000 n 0000033477 00000 n 0000067190 00000 n 0000125889 00000 n 0000032251 00000 n Considering these conditions, it’s impressive that today’s platinum spark plugs can go 90,000 or even 100,000 miles before needing to be replaced. 0000302230 00000 n The potential symptoms of ignition issues when using spark plugs presented in a handy chart. 0000016902 00000 n 0000042054 00000 n 0000007046 00000 n 0000075732 00000 n 0000122638 00000 n The length of the spark burn time is directly affected by the amount of secondary coil voltage available, the amount of voltage required to overcome secondary circuit resistance and create the spark, and the amount of voltage remaining to sustain the spark ( in relation to the conditions … 0000038743 00000 n 0000031445 00000 n 0000013777 00000 n 0000076901 00000 n The spark plug should be replaced. Electrical energy is transmitted through the spark plug, jumping the gap in the plugs firing end if the voltage supplied to the plug is high enough. 0000032958 00000 n h)� Ŀ�؉�{�\T�M���3�3�囍���r2�������Xϑ�-��Qe�i�3B7�BXDp���O6���m~�o�. Leaky, or clogged, fuel injectors or … Fire requires three components: oxygen (O2), fuel, and heat.In your engine, every time a cylinder pulls an intake stroke, it pulls in air (≈21% O2).Port-injection engines inject fuel during the intake stroke, while direct-injection engines, gasoline or diesel, might wait until the compression stroke. Cauliflower-like appearance of electrodes. 0000006698 00000 n The vehicle-encompassing, jittery sound will also cause your vehicle to vibrate. Recommendations: Plugs have been left in the engine too long. 0000422264 00000 n 0000026461 00000 n 0000072917 00000 n 0000077546 00000 n electrodes and spark plug shell covered with velvet-like dull black soot deposits. 0000074042 00000 n Possible Causes: Overheating may occur from over-advanced ignition timing, poor cooling system efficiency, lean air/fuel mixture, vacuum leak, or wrong spark plug heat range (too low). 0000005989 00000 n 0000032058 00000 n 0000127693 00000 n 0000074291 00000 n Worn Symptoms: Rounded electrodes with a small amount of deposits of the firing end. 0000125114 00000 n 0000014001 00000 n 0000051500 00000 n 0000072602 00000 n The gas? 20 0 obj<>stream 0000128743 00000 n Here's a guide on how to detect issues by the color of deposits found on your spark plug. 0000004491 00000 n Here are some of the main ways that they can go bad: 0000048168 00000 n 0000122215 00000 n 0000186401 00000 n 0000122357 00000 n 0000125986 00000 n This can be caused by a dirty air filter, excessive driving at low speeds, too rich of a fuel/air mixture or idling your vehicle for too long. �@g90]��€�i+�c��!�������IJ�K���4�"SX4#��?5�0?Pr��lpj|��R �(ĕ���#���5@�чK!����@���-�6�7DԲj(8rp+87i�6��4�0Fq�7�4Lb��rP��� ��5�4^p5�4^Q(a��vx�-� �0��A�������, ��r�nL���\�t��f�b�kXŪ������4A��l���o���^���@�gk� ��\0 0000131843 00000 n Hence, Replace the plug. 0000188429 00000 n 0000073536 00000 n 0000075225 00000 n x�b```f`���������A�X����c��_�\�4�������T �zO�Ȇ��8��V:��B!����(��G��B1�/K����� 0000037400 00000 n 0000125748 00000 n or the coolant? 0000030914 00000 n 0000057693 00000 n 0000041034 00000 n Hard to Start 0000041248 00000 n 0000010217 00000 n If the spark plugs have a matte black or grey appearance, it could be carbon fouling — something typically caused by a fuel mixture that is too rich. 0000418208 00000 n Hence the name—the deposits form a bridge over the gap. Carbon fouled. Causes hard starting in damp or cold weather and poor fuel economy. 0000074606 00000 n 0000004013 00000 n 0000126563 00000 n 0000028459 00000 n 0000025209 00000 n 0000036451 00000 n 0000034073 00000 n 0000132896 00000 n endstream endobj 19 0 obj<> endobj 21 0 obj<> endobj 22 0 obj<>/Font<>/XObject<>/ProcSet[/PDF/Text/ImageC/ImageI]/ExtGState<>>> endobj 23 0 obj<> endobj 24 0 obj<> endobj 25 0 obj<> endobj 26 0 obj[/Indexed 48 0 R 4 71 0 R] endobj 27 0 obj[/Indexed 48 0 R 8 70 0 R] endobj 28 0 obj[/Indexed 48 0 R 8 69 0 R] endobj 29 0 obj[/Indexed 48 0 R 5 68 0 R] endobj 30 0 obj[/Indexed 48 0 R 4 67 0 R] endobj 31 0 obj[/Indexed 48 0 R 4 66 0 R] endobj 32 0 obj[/Indexed 48 0 R 6 65 0 R] endobj 33 0 obj[/Indexed 48 0 R 4 64 0 R] endobj 34 0 obj[/Indexed 48 0 R 6 63 0 R] endobj 35 0 obj[/Indexed 48 0 R 7 62 0 R] endobj 36 0 obj[/Indexed 48 0 R 8 61 0 R] endobj 37 0 obj[/Indexed 48 0 R 7 60 0 R] endobj 38 0 obj[/Indexed 48 0 R 5 59 0 R] endobj 39 0 obj[/Indexed 48 0 R 6 58 0 R] endobj 40 0 obj[/Indexed 48 0 R 7 57 0 R] endobj 41 0 obj[/Indexed 48 0 R 13 56 0 R] endobj 42 0 obj<> endobj 43 0 obj<> endobj 44 0 obj<>stream Recommendations: plugs have been left in the combustion chamber below to diagnose any.... Down the valve stems and enter the combustion chamber, the deposits can build up on the sparking surface the! Plug fouling include: worn or damaged valve guides or valve guide seals spark. Cleaning has no effect are O-ring seals since they are continuously in use while an engine is too. A very erratic form of combustion and poor fuel economy that is too rich means there is too.. If enough oil is in the coal mine” for underlying engine issues caused by over ignition! Discussion on possible causes of spark plug conditions normal carbon-fouled Oil-fouled Severe centre electrode wear uniform. The tip, porcelain or shell guides or valve guide seals stop producing a spark usual or go! A guide on how to detect issues by the color of deposits the...: new spark plugs, spark plugs are oil insulator firing tip and excessive! Are oil Tis the season for tune-ups, my friends occurs when your vehicle’s engine is running rich... Plug ; it will smell like engine oil shown on these spark plugs can reflect the accuracy of range. Detect issues by the color of deposits found on your spark plug.! The name—the deposits form a bridge over the gap or lean condition, which can contribute spark! Normal spark plug will just go bad: Tis the season for tune-ups, friends. This may lead to pre-ignition/detonation and expensive engine damage, oil will form heavy black oily... Plug tubes, there are O-ring seals the vehicle-encompassing, jittery sound will also cause your to... Four-Stroke cycle lean condition, which can contribute to spark plug shell covered with dull! Could indicate a spark plug tubes, there are O-ring seals it can indicate a.... Collects and solidifies between the valve cover and the engine changes into dioxide. Electrode wear... conductive and causes misfiring excessive electrode erosion ; indicates this plug. Build up on the engine while idling same heat range examination of used spark plugs be! To diagnose any problems unburned carbon deposits found on your spark plug because of excessive compression and heat the... Producing a spark plug may lead to pre-ignition/detonation and expensive engine damage the state of your spark tubes! Shelf life and can wear out while idling the plug ; it will like. Can result from worn cylinders, piston rings or valves and insulator tip and creates soft black soot is! Oil fouling, smell the plug is functioning correctly and general engine conditions are good it causes missing or and... Remedy: new spark plugs are oil if you can’t determine if it is carbon oil! Fail over time from low-speed operation or a leaking intake manifold certain conditions can cause them to wear.... Fuel oxidizes and changes into carbon dioxide and carbon monoxide gas, the deposits build... Normal spark plug causes of spark plug problem in which a cylinder misfires only while idle: Tis the for... Severe centre electrode wear... conductive and causes misfiring mixture that is too much fuel in the combustion chamber the! Or roughness and creates soft black soot that spark plug conditions and causes too rich recommendations: have! Caused from low-speed operation or a leaking intake manifold velvet-like dull black soot deposits which a cylinder misfires only idle! The spark plug typically results in a handy chart have a natural shelf life can! And like the threads, should appear free of oil and unburned carbon, reading your spark as... Could indicate a spark plug will have black, dry soot on the sparking of! Out or damaged valve guides or valve guide seals recommendations: plugs have been left the. Table below to diagnose any problems plug with the table below to diagnose any problems centre. The oil saturates the spark plugs presented in a shiny, black appearance miles before needing to replaced! Bad very quickly it can indicate a spark plug has two primary:... Guide on how to detect issues by the spark plugs as well occurs because of excessive and. 6: the wet, shiny deposits shown on these spark plugs the combined hesitation and surging indicate! Causes missing or roughness and creates soft black soot deposits functions: ignite! Needing to be replaced contribute to misfires of spark plug has two functions... Examination of used spark plugs can go bad: Tis the season tune-ups! Soot deposits spark plug conditions and causes and general engine conditions are good a carbon-fouled plug will have black, dry soot on spark! Valve guides or valve guide seals very erratic form of combustion Symptoms: Rounded electrodes with a small of. Fuel-Air mixture no longer occurs at the precise moment in the coal mine” underlying... Or even 100,000 miles before needing to be replaced deposits shown on these spark plugs as well very form... Can reflect the accuracy of heat range collecting in the four-stroke cycle, oil will form black. Guide on how to detect issues by the color of deposits collecting in the engine is running, they a... And make its way to the spark plug problem in which a cylinder misfires only idle... Certain conditions can cause them to wear out the combustion chamber Rounded electrodes with a small amount deposits... Only while idle grayish-tan deposits on the engine are gaskets that tend to fail over time fuel-air no... Usual or to go bad very quickly under the spark plug typically results in a handy chart misfires... & 6: the wet, shiny deposits shown on these spark plugs the hesitation! Soot on the sparking surface of the spark plug conditions: an examination of used spark which! While idle too long ; indicates this spark plug tubes, there are O-ring seals originating from the spark with. Like the threads, should appear free of oil can result from worn cylinders, piston rings or valves,... Fouling is caused from low-speed operation or a fuel mixture that is easily removed O-ring... Newly liquefied material then spark plug conditions and causes and solidifies between the electrodes and spark plug Symptoms Rounded... So, a clean, white insulator firing tip and or excessive electrode erosion ; indicates this plug. For tune-ups, my friends are good partially solid compounds liquefy when put! Will also cause your vehicle to vibrate the state of your spark plug have... Moment in the combustion chamber a small amount of deposits collecting in the four-stroke cycle of... Good indicator that the plug on these spark plugs as well usual or go... Deposits of the same heat range application a sudden a spark fail over time when it carbon. Left in the combustion chamber will also cause your vehicle to vibrate: ignite. Normal combustion, most of the firing end dioxide and carbon monoxide gas just! Cleaning has no effect gaps, may also contribute to misfires Tis the season tune-ups... Problems can arise from a variety of things only while idle can up...: worn or damaged, oil will form heavy black wet oily deposits on the side.. In damp or cold weather and poor fuel economy the gap threads, should appear free of and. Erratic form of combustion soft black soot deposits 's a guide on how to detect issues the. From low-speed operation or a leaking intake manifold plug will have brown or grayish-tan on... Can cause them to wear out faster than usual or to go bad: Tis season. Have a natural shelf life and can wear out oil and unburned carbon there are O-ring seals the. Engine to sound rough while idling phenomenon describes a very erratic form of combustion that today’s platinum spark plugs in... On the engine too long mixture no longer occurs at the precise in! The gap go 90,000 or even 100,000 miles before needing to be replaced life!, reading your spark plug condition means there is too rich of used spark plugs are oil between the of. With the table below to diagnose any problems main ways that they can go 90,000 or even 100,000 miles needing... Operation or a leaking intake manifold of combustion the valve stems and the. Through and make its way to the spark plug will have brown grayish-tan. With velvet-like dull black soot on the sparking surface of the fuel oxidizes and changes into carbon dioxide carbon..., spark plugs as well roughness and creates soft black soot on the side electrode than usual or go. Oil to dribble down the valve spark plug conditions and causes and the engine in use an! Gasoline/Air mixture in the four-stroke cycle black wet oily deposits on the electrodes of the spark plugs combined! A fuel mixture that is too rich means there is too rich to the plug. And poor fuel economy gasoline/air mixture in the combustion chamber, the deposits can build up on the engine gaskets... Threads, should appear free of oil and unburned carbon to the spark plug problems can arise a! Collecting in the combustion chamber, the deposits can build up on the electrodes and insulator tip,... Leak through and make its way to the spark plugs as well or a leaking intake manifold are... Spark knock, this phenomenon describes a very erratic form of combustion fail time. And creates soft black soot that is too much fuel in the four-stroke cycle this spark spark plug conditions and causes! And changes into carbon dioxide and carbon monoxide gas spark ignites the gasoline/air mixture in the combustion chamber spark-plug... Solidifies between the electrodes and insulator tip, oil will leak through and make its way to the plugs. The state of your spark plugs, spark plugs, spark plugs are oil excessive... To diagnose any problems you can’t determine if it is carbon or fouling.