Lean spark plug reading chart
Apr 04, 2019 · Back in the day, cars had a lot of ignition parts that today don’t even exist. 2. Certainly, An engine’s condition can be judged by the appearance of the spark plug firing end. 5:1 chemically-correct level it becomes extremely detonation-prone. You need to check if there is any problem in the cooling of your engine, or there is any scope for lean fuel mixture or incorrect A spark plug’s heat range is a major factor in engine tuning, and as a result, should be given the attention that it deserves. If the tip of the plug is any other color or condition, it indicates an issue with either the engine, the fuel system, or the ignition. It shows if oil or coolant is leaking into the cylinder. 8 that these symptoms reveal for individ-ual cylinders: Falling spark line. The above plug from a nice clean mid 9 second pass, this one was a little bit lean, added 1 psi fuel to it and picked up 3 mph. It is one of the first places to look when there is a problem with drivability. Over advanced ignition timing. If your motorcycle does not seem to be running right, take a look at the spark plugs. On this pass I had 25% Ethanol on the fuel mix as per my E-85 tester. I got all this from a Free I think their Hot-but-OK plug pictures are a bit too hot for me. com Nov 16, 2012 · Heat range is the speed at which a spark plug can transfer heat from the firing tip to the cylinder head water jacket and into the cooling system. The Colortune spark plug is screwed into the engine in place of the normal plug. Repeat this process until you get a good tannish brown plug reading. A spark plug can be a great indicator of what is going on inside the engine's combustion chamber. In our drag race engine testing, we ran a test program for various percentages of nitro ranging from 6-percent up to 30-percent. mal spark line and five patterns with ab-normal spark lines. " Proverbs 11:14. 6 Cold or Rich But OK. So to prevent you from failing Spark Plug reading here is a multitude of counsellors in picture form. Inspect the engine's spark plugs if there is a misfire, dead cylinder, or if there is a suspected mechanical failure. The color of the insulator is just one aspect of reading a plug as the photo in Jack's post indicates. Spark plug insulator should be a nice uniform tan or brown color if the mixture is just right. (for example if you determined your correct main jet to be a #188 at 95 4 Feb 2019 Are we running lean or too rich? Do we have an issue with the ignition timing or the oil ring? These are some of the things that a spark plug can 7 Jun 2020 Air/fuel mixture is too rich, the carburetor settings are incorrect, or the flame arrestor is dirty or has mounting problems. All are lean, rich or detonating. When the A – F setting is lean due to a faulty fuel system, the combustion temperature may rise, resulting in abnormal combustion. As a result, the market for a premium plug was born. com sion indicates this spark plug con-dition. Any unusual colors Try to use a too-cold spark plug and you very likely will have to jet for a lean mixture to avoid plug fouling - and as you lean an engine's air/fuel mixture down near the roughly-14. Which are the OEM makers of your Honda / Acura Spark Plug. white = lean and black = rich from what ive been told. 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. I suggest visiting a plug site like NGK and reading what they tell you about plug reading. No overheating. High resis-tance between the distributor cap and the plug due to corrosion in the cap or cable terminals. the plugs abilities so we don’t expect it to do Lean running conditions: If your engine is running too lean, the spark plug will be white. I have an E-85 mix on the car and use a tester prior to filling the tank to make sure of the percentage of E-85 that I am running. 5 Fig. Heat range of plug correct. A little lean can make good power, but being too lean can melt a piston. 1 Mar 2004 Spark plugs are an often overlooked but crucial part of a race engine and focus on The ability to "read" a set of plugs is an old-school skill, but it is still Cause : Incorrect mixture setting on carburetor, causing rich condition. electrodes and spark plug shell covered with velvet-like dull black soot deposits. 19 May 2014 Page out of a Haynes Manual showing spark plug readings Death white or gray is too lean (too much air, not enough fuel), black and sooty is 2 Apr 2012 The white porcelain is showing a lean condition at WOT, it's not too far advanced as the total timing mark or color change is right in the apex of the So to prevent you from failing Spark Plug reading here is a multitude of counsellors in picture form. Jan 30, 2020 · Spark Plug – How Do I Read My Spark Plug Condition – What They Tell You 1. Therefore, since the spark plug is the initiating factor in this mysterious combustion process it is imperative that we understand, 1. When these conditions prevail, even a plug of the correct heat range will overheat. At the same time a spark plug temperature exceeding 1450* increases the likeliness of pre-ignition and detonation. Check the owner’s service manual to determine the exact location of the spark plugs. Then I adjust the tune accordingly. Probably one of the most informative small engine manufacturer websites online is the Kohler engines’ site. Spark Plugs ¶ The Bible tells us---"Where no counsel is, the people fail: but in the multitude of counsellors there is safety. Reading Spark Plugs - RED Color. #1. the basic design and materials so that we can make a proper selection 2. Feb 28, 2007 · It might seem like a simple task to some, but spark plugs can often be overlooked during routine maintenance. Apr 03, 2010 · i finally got around to buying a new spark plug and spark plug socket so i can tune the High jet screw on my little bike. Normal Condition. A The damage to the spark plug is a result of the events and the high frequency shock wave. If it has a spike and a short burn time, it is a sign there is an open in the wire or boot preventing the energy from going to the plug. F. The eye loop or any good magnifier is necessary to truly read a plug as well as knowing what one is looking for. The engines cooling system Spark plugs: a critical part of the combustion process . 6 Fig. Joined Nov 28, 2008 Messages 867 Location Sparks, NV Jun 16, 2010 For a two-stroke engine, having a fresh spark plug is incredibly important. Please note that detonation is a different event than pre-ignition where the mixture is ignited by usually hot spot, glowing carbon deposit or overheated ground spark plug electrode, prior to the mixture ignition by spark form spark plug. Engine running rich - You can foul your spark plug by having too much oil and/or fuel. Figures 28 and 29 . Spark Plug Readings. BUT, BEWARE THIS IS ON THE EDGE OF BEING TOO LEAN. So, If your vehicle has a little less spunk lately, it might be time to change your spark plugs. If the "color" of the ground strap "changes" too close to the ground strap's end, (which is above the center electrode), then the heat-range is "too cold" , meaning that the strap is loosing heat too quickly to the base ring, and is not able to burn off deposits until If the firing end of a spark plug is brown or light gray, the condition can be judged to be good and the spark plug is functioning optimally. In general, you´re looking for a spark plug that is dry and has a coffee color without too much carbon (a little carbon is no problem). How to read a spark plug. Chances are the plug will be white, indicating a lean condition. Be aware that the use of 100LL will turn all these readings to a greyer color, but general appearance will still be similar. Like spark plug wires. The white porcelain is showing a lean condition at WOT, it's not too far advanced as the total timing mark or color change is right in the apex of the ground strap curve. This is spark plug reading chart for you:- 2. will publish information about the characteristic markings in spark plug reading charts. Heat Range: (click for larger image) Heat Range = Ground Strap, the ground strap indicates the heat-range of the spark plug. By "reading" the color of the plug you can tell a lot of things about how the engine is running Hello everyone, I would like to get some feedback on reading this plug. Now that you have taken an accurate plug reading and corrected any unusual patterns, it’s now time to analyze and solve the indicated problems. This leaves high molecular weight fractions of fuel that will not burn, but eventually deposit (condenstate) on the in May 15, 2016 · The guys from Jets ‘r Us wrote a detailed guide on how to “read” your spark plugs, including pictures: check it out here. Engine is in order. For best and optimum performance it is always best to go with these plugs. 4 Sep 2014 Black carbon build-up may indicate too rich a fuel mixture or low voltage in the ignition (such as when cracked plug wire insulation is allowing Don't idle the engine, now remove the spark plug and look at the insulator (the white porcelain part) as a A gray ashy or white reading means its running lean. After reading many times about different plugs and seeing new ones come out. Plug heat rating too low, permitting the plug to exceed the optimum operating temperature range of 1560 - 1830 deg. I have two Harleys, both with performance motors; one carbed and one EFI. Abnormal combustion such as knocking. So you should check your plug often. Reading a spark plug correctly: (clickable chart) There are two different main ways to read a spark plug. 7 Too Hot or Lean Pre-Ignition Range. Your main jet should be rich enough that it is just a size or two below the “sputter ” point when a new spark plug before it becomes coated with darker deposits. Enter the use of Jan 31, 2018 · Anatomy of a spark plug: 1) The ceramic insulator's properties affect the heat range of the plug. 8 Jan 2019 This indicates a rich running engine that was probably down on power. SHARE It might seem like a simple task to some, but spark Jun 16, 2020 · Causes can include the engine overheating, incorrect spark plug heat range, a loose spark plug, incorrect ignition timing or too lean of an air/fuel mixture. 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 !! A clean, white insulator firing tip and/or excessive electrode erosion indicates this spark plug condition. When reading the plug, don't pay as much attention to the bit at the top of the threads. Reading a Spark Plug. I hope I never see the others. To avoid this problem, you can purchase a “piggyback” probe for your engine monitor that will screw into the threaded boss on the cylinder, and that will allow the factory probe to be piggy-backed on top The amount of voltage it takes to fire a spark plug depends on a number of variables: spark gap (the distance between the center electrode and ground electrode or electrodes if the plug has multiple ground electrodes); the amount of pressure inside the combustion chamber; the engine’s compression ratio; if the engine is naturally-aspirated or boosted; the type of fuel used (gasoline, ethanol The Chrysler Lean Burn engine control system: first onboard auto computer. This caused my idle mixture to run so lean, even with the mixture screws open far. Spark plug porcelain indications can occur when running low percentages of nitro with methanol. Note: Might need to take a bit of timing out of this tune up or use a colder plug, some deterioration on the center electrode however ground strap looked ok. Excessive spark advance is even worse in its ability to produce detonation, and when combined Pull the spark plug and take a reading. low speed driving/short trips; Spark plug heat range too cold; Air/fuel mixture too rich; Feb 24, 2015 - A spark plug delivers electric current from the ignition system in auto repair How To Read Spark Plugs Engine Repair, Car Engine, Car Repair, Led Light Bar Wiring Diagram Pretty How Wire Without Relay Present Within 9 Jun 2012 When reading a spark plug there are four different places to look. I had cleaned a spark plug and stuck it back in, this is what i found after some miles. Fouled or defective spark plugs don’t let the engine start smoothly. The heat range is established by the distance the heat in the center electrode and insulator ceramic must travel before it contacts the steel body of the spark plug. Excessively engine operating temperatures. You must cut the plug in half and read it where the insulator meets the shell. chart. Interpreting Secondary Ignition Wave Forms On modern coil over plug (COP), wasted spark or coil near plug systems you are using the secondary waveform as a Lean air/fuel mixture ; Spark plug heat range is too hot for operating condition of the engine ; Plug is not properly gapped and/or torqued onto head ; Overly advanced timing ; NOTE: A detonation problem would show signs, such as silver specs, black specs, or melting or breakage at the firing tip. ossaengineering. the factors affecting the plugs performance so we can most effectively use this plug 3. The plug is showing me by the deposits on the tip of the electrode and also the deposits right on the edge of the threaded body. Spark plugs are one of the most misunderstood components of an engine. Extra jets are always needed so the engine can be adjusted to meet changes in the climate. First, clean 25 Jul 2009 Air/fuel mixture is too rich, the carburetor settings are incorrect, or the flame arrestor is dirty or has mounting problems. A spark plug is said to be "cold" if it can conduct more heat out of the spark plug tip and lower the tip's temperature. If the spark plug is black and oily, they are oil fouled. How to read spark plugs for rich/lean conditions with tuning tips for dialing in fueling for max power and better combustion without burning up a piston. Engine and spark plug manufacturers publish generic charts containing information about the Jun 6, 2016 - Learn to read your spark plug and find the right carburetor setting Running rich vs Running lean Running rich means the engine is receiving too icu ~ Pin on Gunz ~ Bombs Size Chart Five A chart showing the relative sizes. Check plug temperature value, ignition timing, fuel octane rating (might be too low) and mixture setting (too lean). Spark plug manufacturers use various systems to denote the heat range of their spark plugs. 23 per sparkplug, compared to the “normal” price of $2-4 per sparkplug. Spark plugs have been around as long as internal combustion engines have and are often a misunderstood component. 3 Carbon Fouled. Rectify before piston rings break or valve faces burn. gsparkplug. usually due to operating with an excessively high loaded prop. Run a few more laps at a racing pace and check the plug again. If you are experiencing engine problems, taking a look at your spark plugs is a good place to start. Thread starter primer7; Start date Jun 16, 2010; primer7. Common Spark Plug Conditions-----Addendum: check out Dans MC Spark Plug chart provided by NGK for further diagnostic help! Dec 28, 2017 · Black sparks indicate that the temperature of the combustion chamber is too low. Reading Spark Plugs. From the top down, here are some of the probable problems May 2001 41 Fig. Honda Spark Plug Tech Guide. Spark Plug Condition Identification Insulator nose grayish-white or grayish-yellow to brown. Think it looks better. Mixture setting and ignition timing are correct, no misfiring, cold-starting device functioning. What you can do is to check for problems in your engine’s cooling, a lean fuel mixture or incorrect ignition timing. However, your spark plugs will become either too clean (evidenced by a lack of normal color) or white when your engine is running significantly lean. Normal operation. Here is finally a really detailed look into each and every plug made by NGK & DENSO. May be caused by a foreign object that May 22, 2019 · If your spark plug has started to look white in colour, this indicates that something is making the plug run too hot. I got all this from a Free hand out I recieved from NGK Spark Plugs back in 1977. More specifically, bad Nothing much to worry about. Just physics. Oct 30, 2006 · A standard spark plug might still burn cleanly after 12,000 miles, but its gap may have eroded by as much as . The plugs on the right would probably indicate imminent failure for a 2-stroke. This can be caused by a dirty air filter, excessive driving at low speeds, too rich of Plug Reading - Gas Engines - 4 Stroke The white porcelain is showing a lean condition at WOT, it's not too far must be right as well as the correct heat range on the plug to get true readings. What to do when the weather changes: The temperature, humidity, elevation etc all affect the jetting. If the chamber is too hot, this is most likely a sign of a lean mixture and/or too much timing. 29 Too Hot or Lean The plugs on the left would be OK for a 4-stroke, but in a 2-stroke they are lean, hot, and dangerous. A common symptom of your car running lean is that your spark plugs are clean or turn white. Arcs like to jump from sharp edges. 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 This condition may also be due to improper reach spark plugs that permit the stoppages, low level), a very lean air/fuel mixture, or a leaking intake manifold. www. 6k views Reading spark plugs for racing is a precision technique that should be The most accurate plug readings are obtained after an engine is well tuned with new This is the only place on the plug where you can see if the engine is rich or lean. Spark plug heat range is 1 Jul 2004 In the past, most performance engine tuners looked at the spark plug, the to load up and foul the spark plugs, while if the air/fuel mixture is too lean the the unit will read the exhaust and supply the readings necessary to Air-fuel mixture too lean. The simplest patterns affect all plugs in the rack. Electrodes look glazed; core nose very white; few deposits. Spark Plug Basics. Mar 06, 2019 · The spark plug color can provide evidence of what is happening inside the engine. That type of spark plug cleaner was all the rage about 20 years ago. The problem with them is that they tend to round off the sharp edges on the electrodes that the plug designers work so hard to design. Jul 01, 2004 · The use of an infrared exhaust gas analyzer and/or an extended range oxygen sensor and then reading the spark plugs (for signs of detonation) is the best way to know if the air/fuel mixture is www. Spark plug reading chart, from cold/rich to hot/lean A spark plug gasket probe generally results in a CHT reading that’s about 40F hotter than a normal, threaded probe on the same cylinder. Spark Plugs . Spark Plug Chart It can indicate if there is a rich or lean air-fuel ratio. May 15, 2014 · Have you ever wondered how to "read" a spark plug? This video describes in detail the best process to examine a spark plug and assess its condition. This basic guide is designed to assist the technician, hobbyist or race technician in understanding, using and troubleshooting spark plugs. Not only does it provide comprehensive troubleshooting steps specific to the application and engine symptom, a brief read of the material results in a combustion engine fundamentals refresher. This area is prone to have some minor carbon build up no matter how well the plug is running. 22 Mar 2019 Two-wheeler spark plug maintenance - how to check the electrode for too lean or rich air-fuel mixture, how to clean the spark plug and how to replace it. If you are using pump fuels rich with additives, those chemicals 'clean' the plug making it always look fine. 4 Too Cold. It should have three or four smooth humps. May 01, 2020 · Place the plug in the spark plug socket with the threads facing out. If it were running a tad bit leaner, the plug would have more of an tan/ash color to it. It's also the litmus paper for reading timing and fuel mixture. Air-fuel mixture too lean. 1 Oil Fouled. But no matter how exotic or mundane, all cars still use spark plugs. If you notice any black, dry soot on the spark plug, this is a sign of “carbon fouling,” which means your engine has been running too rich, and you should visit a mechanic to figure out the cause. This happens if the ratio fuel/air is too high. So, If the firing is brown or light gray, the condition can be judged as good. Normal Appearance: A light tan/gray or brownish color, along with very little electrode erosion, indicates optimal operation conditions, including a healthy engine and correct spark plug heat range. A spark plug is said to be "hot" if it is a better heat insulator, keeping more heat in the tip of the spark plug. Plug is overheating. Now, I’m going to cover the 3 most common conditions, lean, normal, and rich. Most often, a light tan color around the tip of the spark plug indicates a healthy and well performing engine. Spark Plug Reading HOME Reading Spark Plugs Thanks to Larry Meaux of Meaux Racing for providing this information and pictures. And spark plugs wear Apr 25, 2012 · Reading spark plugs is an easy way to determine how an engine is running. They often come with specific instructions on how to remove the spark plug as well as the tools that are necessary for their removal. TREATING · KNOWING YOUR PROP · IMPROVE YOUR PROPS · PROP CHART Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, spark plug and engine damage; It is important to read spark plugs many times during Too cold and the spark plug will cold foul resulting in an engine misfire. No deposits from fuel additives containing lead or from alloying constituents in the engine oil. The spark plug socket has a rubber grommet that will hold the plug in place as you lower it down into the engine and make it easier to thread the plug once you have it in there. October 30, 2017. Check for correct application of spark plug (heat range too hot, wrong spark plug for engine), cross firing of ignition cables, over advanced timing, lean fuel mixture, defective EGR valve, accumulation of combustion chamber deposits, hot spots in the combustion chamber due to poor heat dissipation, improper installation torque applied to spark Dec 20, 2012 · Check out the images below, courtesy of NGK Spark Plugs, and get ready to do a little light reading the next time you pull your spark plugs. That's why the iridium plugs have a serrated tip and a 'U' shaped ground electrode. Now i am able to idle at 700 rpm, with only 1 turn on the mixture screws which brought down the AFR a bit during cruising speeds. that it's slightly fat at idle. When racing with Black, dry soot on the electrodes and insulator tip indicates a carbon-fouled plug. In the case of reading. 31 Mar 2006 If your plug is grey or white, than you know that your engine is running too lean and you need to take steps to prevent engine damage. By Kevin Cameron. Is it running lean? Spark plug type & gap chart for Briggs & Stratton engines Flathead engine spark plugs & gaps Checking and changing spark plugs is an essential step in routine small engine maintenance and when troubleshooting problems with your lawn mower , snow blower or other outdoor power equipment. Dry and Wet Fouling. Unfortunately some spark plugs are very specific to a type of engine and make only for that engine such as the NGK ME8 for $34. The spark plug industry has determined that the ideal temperature of a spark plug under operating conditions is between 950*F and 1450*F*. A few of the symptoms indicated by your spark plug color have simple fixes. Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage It is important to read spark plugs many times during the tuning process to achieve the optimum air/ fuel mixture Overheated plug . Feb 25, 2015 · Echoing Jack and Jeff. Whenever you are rejetting or tuning your carburetors, a plug chop can take away a lot of the guess work. With good air/fuel ratio mixture control, we saw porcelain indications similar to spark plug reading from straight methanol. i know the color is supposed to be chocolaty/brown but this is as close as i can get it w/o going slower than a grandma. If the heat range is too cold, the spark plug will be unable to properly self-clean by burning off carbon deposits. 20 Dec 2012 Is your engine running too lean? Too rich? Is there an issue with oil control or ignition timing? Or is everything just fine with your engine? Like the 15 May 2014 I've seen rich and lean. But who am I to nay say NGK? Cold or Rich But OK. Read on then as we guide you to how you can go about checking this adverse conditions such as heavy traffic, cut the replacement schedule by half. If your spark plugs are fouled or damaged, it can lead to a host of problems including reduced gas mileage, slow acceleration, engine misfires and trouble starting the engine. Spark plugs are generally a brown or grey color, which is caused by normal ignition. Here you’ll find another color chart: spark plug reading. Dry and Wet Fouling Although there are many different cases, if the insulation resistance between the center electrode and the shell is over 10 ohms, the engine can be started normally. The Lean Burn system was an early spark advance control system (introduced in 1976 and continuing to the 1980s) that was troublesome due to the nature of the contemporary electronic components, as well as the yards of vacuum hose and competent mechanics needed to keep it working. Cause: Incorrect mixture setting. 7 Fig. Normal Wear: A light tan or light 23 Jul 2014 Photos of black, carbon-fouled plugs were labeled “Rich,” while Reading and interpreting a spark plug's story in a racing engine requires a more collector, or zoomie-style individual pipes) can affect oxygen readings. Mar 29, 2019 · To read a spark plug, start by checking the color, since an undamaged spark plug will be light grey, or possibly tan. Note the spark plugs completely melted. Spark Plug Reading 101 by Mike Canter, Last Updated Dec 19, 2014 Other than installing thermo-coupler sensors in the combustion chambers the only real way that you know what is happening inside your engine is to read the spark plugs. Choosing the right heat range is crucial for high performance engines. We have Feb 18, 2019 · Remove and Read the Spark Plugs One at a Time. 5 Too Cold. Before I get into describing these common conditions, let’s go over on how one would obtain such a reading through conducting a “plug chop”. A fouled plug may misfire causing low power and efficiency, and a major increment in deplete hydrocarbon (HC) emanations – which may in the end harm the exhaust system. Rich: More fuel less air. Long Apr 16, 2019 · Spark plugs somehow destroy at the end and can end up noticeably fouled via carbon stores. By viewing the colour of the burning fuel/air mixture, you can tell whether the mixture is too rich, too lean or correct. As a result, the spark plug is functioning optimally. 7) Reading plugs :At this point it is best to do a plug check, go to FAQ-READING PLUGS. 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. 7 Jun 2020 This article will cover the basics of spark plug reading. Doesnt cause much Spark plug electrode have a reddish brown kind of color. 2 Oil Fouled. May 31, 2017 · Sorry the pictures arent the best but let me know what your think, 32:1 91 octane with 927 castor ( I usally run yamalube 2r) Not sure if the jetting but I think its stock 600 m above sea level I ride somewhat hard but not full throttle all the time I go in the trails and the track. Spark Plug Readings from Air Density Changes. The graph shows a relative narrow range for the lean and rich limits of the air/fuel ratio, which will then provide which is often referred to as “Reading” the spark plug. Plug Reading Chart - Too Lean Too Rich Compare and Find Out : Dirtbike : A large number of emails I get in my DON T ASK column deal with jetting. Less than 950* and the chances of a plug “fouling” becomes greater. Below is some good charts to help read the spark plug and determine what adjustments to make. Start your tuning process by going to a larger main jet. Ricky Chu – Feb 28, 2007. I think their Hot How Do You Read A Motorcycle Spark Plug? Cycle World Technical Editor Kevin Cameron answers your motorcycle engineering and mechanical questions. Spark plug heat range is Many tuners will simply learn to read spark plugs, as this is clearly the plug, and/or EGT readings, and start out on the rich side and work your way down. Jul 27, 2014 · Pretty sure your plug labels are incorrect; the rich one is right but the lean and optimal should be swapped round… a lean mixture increases the heat of combustion and tends to glaze the ceramic of the spark plug and burn off any deposits that may have accumulated, leading to the very white, clean insulator on the right of the picture. (carburetor fuel injection); mixture too rich, plugs makes for a good plug reading that is darker than most would expect to see . The threaded portion of the spark plug is the same end as the electrode. Follow the steps below to learn how to read your car’s spark plug. 010-inch. lean spark plug reading chart