No Spark On One Cylinder

My engine fitted with a starter motor. I just recently purchased a 2006 330 X I for my wife, with a misfire in cylinder one. If you replaced the coil first and had a shorted out spark plug or shorted out wire on that cylinder, it's possible that you killed a single cylinder's coil winding in the new coil in the same way the old one was bad. The valve was just hanging down into the cylinder. This is a tricky one but I’ll bet the distributor is out of phase. * Both coils are good by ohmage and have been used on the good and bad side. The coils have 0. Even if only one cylinder misfires, check each spark plug and compare its condition with the rest. BUT, cyl #2 is the one not producing. New issue, No spark in one cylinder. I appreciate any ideas. Check for one or more possible malfunctions: No spark or weak spark to one cylinder. You can use a cheap spark tester tool for this. It seems that the coil packs are not getting a signal. P0304 – Cylinder 4 -misfire detected after chaking all iam see problem i injektr tow wairs one+ and one- flash when start motor -flash wair- flashing abaut 30 sek. The cure here might be to switch to a one-step hotter spark plug. 2012 Honda Civic Si, Dyno Blue Pearl Re: Cobalt has a misfire on cylinder 2 [ Re: DreamerGT ] #2578821 03/25/12 09:05 AM. What part is bad? Swap coils from the dead cylinder to a live one to see if the problem follows. When it gets light out tomorrow, I will pull that wire and check for spark too. Everything else seems fine, have gas, oil level is good, ran machine for 3 hours yesterday and no problems. Car Has No Spark To Spark Plugs. then i noticed that THE TIP WAS MISSING?!!??!?!?! Missing tip:. The spark plug has a rubber-coated wire attached to the top of the porcelain spark plug. You may not be getting enough juice to the engine. Boat would run with no problem. Just how did to test for these two things? You did test for spark under compression and checked compression with a leak down test, right?? I agree you might want to pull the valve cover and take a peek if you can get to it easy. The car has 110,000 miles. Let me give you a waste spark story. With ignition On, turn the engine pulley CW past the TDC mark. What about the small box next to the CDI, is that the rectifier? Can it cause any issues with spark? The bike fires on the first kick, and idles fine, but you can't see any smoke from the left, pipe never gets warm, and when you accelerate, there is no power (running on one cylinder). While we are on the subject of grounds, be sure all the coil, CDI pack and mounting bracket ground leads are clean and have continuity. Swapping the leads on the ignition coil. The hookup for the "good" (vertical) cylinder makes pulsing voltage in one of its two wires when the key is in and ignition is pressed, but not otherwise. Was out riding recently had the bike drop to one cylinder on the trail. It seems that the coil packs are not getting a signal. If the misfire goes to #2 cylinder, you have a fouled or failed spark plug. I can pull plug wire on #2 and no difference. Over 7 Million Items. When I pulled the left spark plug again, it only VERY faintly smelled like gas. Different ecu, igniter, injector, harness and still the same dead cylinder. 8L engines that have experienced a blown out spark plug. Basically, the rear half of the coil has spark, but makes no difference on either cylinder and it is running on the front half of the coil only. That dual-terminal coil is probably two coils in one so I suppose that one side could fail and the other still work. This result means one of two things: either that the spark plug wire is BAD or the ignition coil pack is fried. So I am checking the coils. There just are no short cuts. i made sure to keep the pos wire on the pos terminal of the coil pack. It was the first one I worked on and I may have been too careful with it and not clean agressively enough. I have no spark on 1 cylinder on a 1986 evinrude outboard 110 Hp. I'm guessing the next thing to suspect would be a bad coil pak, although I don't understand how it could fail to deliver spark at only one terminal as each of the three internal coils drives two terminals, or cylinders. Average repair cost is $700 at 118,300 miles. A Motorcraft one will set you back around $100. I plugged that coil to wire #2 and it worked. It is getting gas but no spark. Replace only one spark plug at a time. i have an HEI spark detector and i checked it and there is no spark i did find a short in the wiring which i believe couldve caused all of this there was a wire melted and grounding out on my exhaust which was causing my PCM fuse to blow i fixed that and so far every fuse and sensor that that wire is connected to has been blown could that short have blown my PCM?. One further step down this path is to spray the engine with an electrical spray cleaner solution of some kind. Still good spark. And since it draws from the intake on the # 3 and 4 cylinder side its drawing all air and no fuel so the two cylinders are dead. Compression on all cylinders are at 125psi. We were a few miles out of town when the one (mag side) cylinder quit cold. This approach is termed "wasted spark" and is widely used. Use your jumper wire to connect the spark tester to a good ground. Also if you get intermittent spark or only firing on one cylinder, you may have a bad connection at the boot end where the boot goes over the spark plug. 1 is working so should No. Not sure how to check the CDI unit. But still have no spark to the spark plug. with kawasaki FD440V ( Vtwin ) Only one coil will fire, if i switch the coils still just the one side will fire. BUT, cyl #2 is the one not producing. Boat would run with no problem. BUT, cyl #2 is the one not producing. The symptoms you describe are classic "dying coil" symptoms. The problem was the vacuum line from the purge valve for the fuel vapor canister was cracked in half. checked all wiring. Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. I changed the distributor cap, rotor, and wires. How to stop this from happening? Well, before you know how to fix low compression in one cylinder, you should have basic ideas about the reasons that cause the problem. Like the title says one cylinder isn't firing. 012 clearance. Other issues that I have seen/read that have caused a no spark/bad running issue: A. Also if you get intermittent spark or only firing on one cylinder, you may have a bad connection at the boot end where the boot goes over the spark plug. Could be a defective igniter unit or ignition coil for that cylinder. Ive got no spark at the spark plugs. The coils have a diode between them to prevent one interfearing with the other. There is also a module that plugs in right beside the big main harness plug. In this guide, we'll walk you through the steps of how to fix low compression in one cylinder. I am just disgusted with myself for being a parts changer, instead of me actually diagnosing the real problem before I started working on the motor. So if I understand correctly the signal comes from the ecu goes to the igniter and then goes to the coil pack harness. The ignition coil is truly an amazing little device. What I have found out is that there is a possibility of one cylinder having a weak spark. I can pull plug wire on #2 and no difference. No spark on one bank of cylinders. We have visually checked and replaced the intake gaskets. You should have a reading of at least 150V or more. I swapped the igniter coils, and both coils work on the right side (but neither work on left). Fortunately, they pulled off the valve cover and saw that one of the valve springs on that cylinder had straight-up snapped. with kawasaki FD440V ( Vtwin ) Only one coil will fire, if i switch the coils still just the one side will fire. I ordered a replacement coil, and took off the shroud to begin the replacement. so when we first installed this used cdi the belt light went off and stayed off but still had no front spark. No Spark on One Cylinder: This can be caused by a defective blocking diode in the other switch box. Update: So he purchased a wiring specialties harness, installed it and is still having the same issue (No life on cylinder 1). The hookup for the "bad" (horizontal) cylinder makes constant voltage in one wire when the key is on, no voltage in the other wire, and no change at startup. Today I thought I would swap out no 3 coil with one of the other coils as they were getting a good spark to see if the coil was my problem, I decided to just check cylinder 1 and 2 again to ensure there was good spark and to my dismay now I have no spark. Once it dries out, everything should be fine. The Digital-7 Plus provides racers with two smooth rev limits, one for top end overrev protection and another to activate with a clutch or transbrake switch for use on the starting line. To be honest, it is not because MB cars are weak in this area, but because most owners forget that spark plugs are wear items and need to be replaced at the recommended intervals. if i swap the coils i still get spark to the rear cylinder but no spark to the front cylinder (no matter which coil pack i use) i switched the 2 small wires on the side of the coil pack one side was blue and black and the other side was a yellow and black wire. I'm getting fuel (checked fitting on the fuel rail) but no spark. Replacing a worn spark plug may get an engine running, but the real culprit may be a carburetor that is partially blocked. I have checked my spark plug multiple times, dry as a bone. We're not talking "it doesn't seem to be firing" but that you know that there is no spark happening on either the front or rear cylinder but not both. Thanks Matt. Turn on the key and crank the engine. Checked spark by pulling the wires off the plugs then off the coil, no spark on 2-3. virago running on one cylinder. i have spark with plug out and connected to wire. Pull the rubber boot from the spark plug and use a socket wrench to remove the blunt plug. Then you can't mix them up, unless you remove the wires from the distributor too. if i swap the coils i still get spark to the rear cylinder but no spark to the front cylinder (no matter which coil pack i use) i switched the 2 small wires on the side of the coil pack one side was blue and black and the other side was a yellow and black wire. 8L Chrysler mini-van, are OK and not the cause of the misfire condition. Boat would run with no problem. Check the O2 sensor on that side of the engine, you will likely find it is dead and no longer working (yes, a bad O2 sensor will cause the plugs to foul). Worn-out spark plugs require higher voltage to produce spark, which adds strain on ignition coils. Im out of ideas now. runs on one. This result means one of two things: either that the spark plug wire is BAD or the ignition coil pack is fried. You can have great compression, but if you have an air leak you may never get the engine to pop. One further step down this path is to spray the engine with an electrical spray cleaner solution of some kind. The coils have 0. So a six-cylinder car will have six contacts on the distributor. The engine starts and runs rough idle and uses a lot of gas. The coils have a diode between them to prevent one interfearing with the other. NOTE: I did not mount the new ICM to the intake manifold because I wanted to know if it was the problem or not. Took it to the dealer and said that the coil was not working. No spark on one Cylinder 87' Virago 535. 8L Chrysler mini-van, are OK and not the cause of the misfire condition. Just how did to test for these two things? You did test for spark under compression and checked compression with a leak down test, right?? I agree you might want to pull the valve cover and take a peek if you can get to it easy. i swapped coils to see if the trouble followed. to/2JbqiL9 Inline Spark Tester to spot the problem https://amzn. Since the partner cylinder is on its exhaust stroke, nothing ignites and the spark is “wasted. "There is never just one thing wrong with a boat"; -- Travis McGee, main character in a book series by John D. Frayed wires somewhere in the wiring harness or under the seat were causing a short; Guy said sled was only running on one cylinder. The minimum in any one cylinder should not be less than 70% of the highest cylinder. It takes 25000 volts to fire the ST-125, if it doesn't fire, you test the circuit as "no-spark" and you'll go right at the problem. Well, “burn up” is more like it, because when a spark jumps the gap between two electrodes, it actually burns off (erodes) minute amounts of metal from each one. Dual fire and single fire. What could cause a misfire even though the spark plugs are ok? After a bit of self-diagnosis with the help of the bloke across the street it appears that no. The coils have a diode between them to prevent one interfearing with the other. He pulled the plug on the bad cylinder and it’s getting decent spark just by visually looking at it, and the plugs are getting fuel as the plug is wet. Check the O2 sensor on that side of the engine, you will likely find it is dead and no longer working (yes, a bad O2 sensor will cause the plugs to foul). Check for water. I have tested the Iginition Coil, both Primery and Secondary sides check within specification and I have replaced the Spark plug wires. Speed in getting this fixed is in high demand, my wife has missed 2 day of work. "No compression" would indicate "zero" psi and that is unlikely unless the piston has the top blown out or one of the valves is held open significantly. There could be other problems like it only running on one cylinder. However, the most common solution to a Deere 425 "no start-no spark" situation is a little stupid module that seems to have been a problem from the first. Cylinder won't hold any pressure. After all, the internal combustion engine simply cannot operate without a spark plug. We only tested the TPS because we ran out of ideas and the service manual actually said to check that as part of diagnosing a no-spark situation, it didnt make sense to us why that would effect spark, and no sense to us at all why it would effect no-spark on only one cylinder but for the sake of being through, we checked it. You want to remove both so that you don’t accidentally fire the one still in a cylinder and “fire” the engine. I plugged that coil to wire #2 and it worked. the insulator and there will be no spark. it did the same thing, only had spark in onee cylinder, the dealer was back and forth with Polaris for ideas to try, everything checked out , so they put a new ECU on again and it is still running fine at about 1700 mi. I have been having trouble with the front cylinder cutting out. P0302 Cylinder #2 Misfire. If there is any water on the spark plug, check for leaks. Fortunately, they pulled off the valve cover and saw that one of the valve springs on that cylinder had straight-up snapped. If this is the case it can be solved by dipping your finger in gasoline and wiping the insolators on each plug. Intermittent spark on one cylinder. 2 ecotec only runs on 2 coil packs and if I had a bad coil I would have lost spark on two cylinders. All coils/plugs work on all other cylinders, however no spark on cylinder 2. as I mentioned before I've looked a the points and they seem to be working properly but I'm not sure what the proper gap spacing is so if someone can tell me that would be one thing I can check. The clutch side cylinder is not getting spark. Curing 2-cycle Engine Problems: Many 2-cycle engines have problems and are sent to the junk yard before their time. I ordered a replacement coil, and took off the shroud to begin the replacement. Ignition Coil Troubleshooting: (No) Fire in the Hole. As performance enthusiasts, we tend to focus on power builders like high-flow cylinder heads, big camshafts, and mandrel-bent exhaust components. The 1982 R100RS (no slash) does indeed have two coils but both fire simultaneously and there is one waste spark in one or the other cylinder per revolution. It is not uncommon to receive a faulted new part. Any ideas or thoughts on what to check. if you miss one and did not see it…. If the reading stays low - the trigger is bad. "No compression" would indicate "zero" psi and that is unlikely unless the piston has the top blown out or one of the valves is held open significantly. This does not appear to be a "wear" issue It seems something has failed catastrophic. I mean none. What the trouble shooting guide doesnt say, in so many words, is that each cylinder has its own circuit through the timing base (trigger). Replacing a worn spark plug may get an engine running, but the real culprit may be a carburetor that is partially blocked. it did the same thing, only had spark in onee cylinder, the dealer was back and forth with Polaris for ideas to try, everything checked out , so they put a new ECU on again and it is still running fine at about 1700 mi. I have an older 1989 Prov 150 with one cylinder not firing. (individual per cylinder) If a cylinder has no spark, and you have swapped the COIL, the LEAD, and PLUG, and the problems stays with the same cylinder, then the cause must be a problem in the POWER PACK or TIMER BASE which affects only that cylinder. Thanks for your help??. Use your jumper wire to connect the spark tester to a good ground. I did not do oil into the cylinder and then repeat the compression test. It was the first one I worked on and I may have been too careful with it and not clean agressively enough. to/2JbqiL9 Inline Spark Tester to spot the problem https://amzn. While a compression test is a dynamic test (engine moving), a cylinder leakdown test (C. You should have your spark restored. 2012 Honda Civic Si, Dyno Blue Pearl Re: Cobalt has a misfire on cylinder 2 [ Re: DreamerGT ] #2578821 03/25/12 09:05 AM. This result means one of two things: either that the spark plug wire is BAD or the ignition coil pack is fried. Left cylinder is still not firing. It is not uncommon to receive a faulted new part. If you have points in your machine the all it takes is a little grease or carbin in a point set to cause a no spark condition. Kohler engines are the premium engines in the market and are known for their dependability and durability. Most (but not all) bikes built before 1980 have points ignition. I mesured ohms and with dva. A "leaky" plug will spark outside the cylinder and not inside because the spark can jump through the air easier than it can jump through the compressed charge inside the cylinder, especially when the engine is cold. Occasionally a timer base will cause this same problem. Then took the coil leads from the right side coil, connected them to the left coil, ran a spark plug wire from that coil to the right cylinder. So i assumed it was running on one cylinder. If still no spark, then do this: on the right side of the motor, toward the front of the gas tank (but under it), there are two ignition coils (black cylinders, approx. I repeated this a couple times with no success. Also check the blocking diode in the engine harness. You say you have spark but might be "weak spark"?I would spin in a new set of plugs, if that ain't it you have a spare set. "There is never just one thing wrong with a boat"; -- Travis McGee, main character in a book series by John D. Both have a blue spark, both rockers on each cylinder are moving. Still No spark, swaped ignition coil with cylinder number One. Check for one or more possible malfunctions: No spark or weak spark to one cylinder. checked all wiring. Disconnect the stop wires from both power packs and retest. What the trouble shooting guide doesnt say, in so many words, is that each cylinder has its own circuit through the timing base (trigger). Basically, the rear half of the coil has spark, but makes no difference on either cylinder and it is running on the front half of the coil only. When I unplug the cable on one spark plug, I see no difference happening on engine performance, while when I remove the cable from others engine starts to struggle. No spark one cylinder. A newer HEI setup, the bad ignition module can also be a sign of no spark. If the other cylinder doesn't run you've found the problem. What the trouble shooting guide doesnt say, in so many words, is that each cylinder has its own circuit through the timing base (trigger). The stator will read from blue. A P0303 code, for example, would tell you that the No. Dual fire and single fire. This means the plug has a higher internal temperature, and is said to be a hot plug. A Short Course on Ignition Systems: by Charles Ofria. To be honest, it is not because MB cars are weak in this area, but because most owners forget that spark plugs are wear items and need to be replaced at the recommended intervals. Two hours later I went to warm it up to change my oil and the rear cylinder was not running again. I am still not getting any spark to that. I swapped them from one side to the other. Boat would run with no problem. Car Has No Spark To Spark Plugs. I repeated this a couple times with no success. 3 cylinder is misfiring. Check the stator resistance and DVA output (see Step #13 on NO SPARK ON ANY CYLINDER above). Check that the spark plug for the engine is free of decay and is clean. The 12inch Square Drop-in Pan with Natural Gas Spark Ignition Kit comes fully equipped to set up a fire pit of just about any size or shape. When I take off the spark plug and spray in there it starts for a bit longer (I figure there is more in the cylinder therefore more explosions) So basically gas is stopped in its tracks at the carb. Unfortunately still no spark to left side. As you read above this is assuming you have checked the basics, you know, gas is on, gas in the tank, choke is on. It should also be bright blue and intense in nature. Troubleshooting my dads Sabre lawn tractor with a twin cylinder 18hp B&S engine. The image below shows a plug off a motorcycle that was running pig rich. Thanks for the input so far. So Ive done the obvious- New coil pack, new plugs, etc. Over 7 Million Items. If the spark plug is working, disconnect the black/yellow wire and/or the black/white wire. Spark has to travel from the coil, through a wire and to a spark plug for each cylinder so each it is possible that there can be issues at any one of these components. We only tested the TPS because we ran out of ideas and the service manual actually said to check that as part of diagnosing a no-spark situation, it didnt make sense to us why that would effect spark, and no sense to us at all why it would effect no-spark on only one cylinder but for the sake of being through, we checked it. Whilst it may seem like one of the simpler components of your engine it is also one of the most important. If one of the ignition coils has failed and the manufacturer has updated the part, your mechanic may recommend replacing other ignition coils with an updated part as a precaution. Swap the coils with 3,4 then switched spark plugs also but still miss fire on 1 and 2. I have checked or replaced spark plugs, spark plug wires, distributor cap, ignition rotor, igniter, and ignition coil. It must do this at exactly the right instant and do it at the rate of up to several thousand times per minute for each cylinder in the engine. Wisconsin TJD no spark on one cylinder discussion in the Lesser Known Classics forum at Yesterday's Tractors. The ECU was replaced and it ran fine again, then less than 100 mi. For your Tecumseh small engine ignition repair that requires Ignition Coils, think Jacks! We have most everything you could want when doing a small engine repair or maintenance. I have also got my coil packs removed,connected, with the spark plugs in and earthed, so i can see the actual spark. Kohler designs long life. 5 OHC (Over Head Cam) engines. This result means one of two things: either that the spark plug wire is BAD or the ignition coil pack is fried. Spark plug worn, fouled or damaged. His ecu has no codes, so it's hard to point it at one thing in particular. Tecumseh IGNITION COILS. Place the equipment stop switch control in the OFF or STOP position. Using piercing probes and DVA adapter or DVA Multimeter, check the resistance and DVA voltage for the bank without spark on the 6-pin stator connector while connected as follows: Note: If the power pack has no spark on one bank and the readings are good, replace the power pack. I have a 73 CB350 and just noticed only one cylinder is firing. I can pull plug wire on #2 and no difference. Ignition Troubleshooting: No Spark The ignition system is fairly easy to troubleshoot in the case of malfunction. The stator will read from blue. I pulled the plugs and the #5 cylinder's spark plug looked like the picture below. You need to check spark with a spark tester set at 7/16". Based on the response posts, now I'm thinking that I didn't get that front carb clean enough. No spark @ Cyl # 2 all coil are good, rotated to every cyl all work but at 2 No power to accelerate from stop, loss of power in higher gears. Fuel seems good and I am going to check timing but if anybody else has dealt with a similar problem please share how you fixed. The spark should be as thick as a pencil lead and produce an audible snapping sound. One of them is for power. I replaced the coil and plug, still no spark. Check that the spark plug for the engine is free of decay and is clean. I get no spark to number 1 spark plug. Plug not firing - Mercury 115hp 4 stroke My father has a 2004 115 Mercury EFI 4 Stroke that one cylinder is not firing. Then I turned the engine over several times with the choke on. It runs on which ever cylinder the plug wire towards the front of the engine is attached to. 5 OHC (Over Head Cam) engines. No spark on one cylinder- Vmax 600 Seems to be a bit doggy and decided the left cylinder isn't firing or only firing part time. The coils have 0. So a six-cylinder car will have six contacts on the distributor. (individual per cylinder) If a cylinder has no spark, and you have swapped the COIL, the LEAD, and PLUG, and the problems stays with the same cylinder, then the cause must be a problem in the POWER PACK or TIMER BASE which affects only that cylinder. Some later design heads have no water jacket around the plug hole. That dual-terminal coil is probably two coils in one so I suppose that one side could fail and the other still work. And in plain English that means no spark, and you’ve got a fouled plug. If you are losing spark on only one cylinder, chances are it is the coil but it could be the power pack as well. I am getting no spark on one of the plugs. Loosening the rockers to release the valves and then connecting air pressure to an adapter at the spark plug opening should isolate the cause of the leak. I ordered a replacement coil, and took off the shroud to begin the replacement. I have tested power coming out of powerpack to each coil and no power to one. If it is not, suspect a defective spark plug for the cylinder in question; If high-intensity spark (for the affected cylinder) seems normal, you may perform a similar test for the fuel injector by carefully disconnecting it to see if any difference in engine RPM is detected. Then how does it reach the spark plugs in the first place? 1. Left cylinder is still not firing. By Tom Benford. Probable Solution to the "Firing on One Cylinder" Issue50MPH at WOT No More!. 8L engines that have experienced a blown out spark plug. It is getting gas but no spark. While we are on the subject of grounds, be sure all the coil, CDI pack and mounting bracket ground leads are clean and have continuity. For no reason. P0302 Cylinder #2 Misfire. Mercury 6 Cylinder Engines with ADI Ignitions If more than one cylinder is not firing: Replace BOTH switch boxes unless you can pin the problem down to the trigger. Turned out to be no spark, front cylinder. This is a tricky one but I'll bet the distributor is out of phase. Seems to me that the spark can probably be left out of the equation,(hopefully), since you had the same problem with different plugs and different coils. If it does spark, check resistance to. 02 Nissan altima won't start. I have a 2010 ranger XP 800 efi that is now not firing on one cylinder. Two Cylinder Engines with Combination CD Module with Built-in Ignition Coils (1984-1988) NO FIRE OR INTERMITTENT ON ONE CYLINDER: Check the stator resistance, you should read 680-800 ohms, DVA 180V or more from blue to yellow (Note - On some two cylinder engines, the stator has two blue wires and no yellow wire. I appreciate any ideas. one of the valves is too tight causing low compression in the cylinder: are you getting a loud pop out off the cylinder with the plug out. If you have points in your machine the all it takes is a little grease or carbin in a point set to cause a no spark condition. I have no manual to assist with dismantling etc and any useful info would be no doubt helpful please?. Fuel seems good and I am going to check timing but if anybody else has dealt with a similar problem please share how you fixed. Fortunately, they pulled off the valve cover and saw that one of the valve springs on that cylinder had straight-up snapped. Weak ignition coil 2. This does not appear to be a "wear" issue It seems something has failed catastrophic. MC21 no spark on one cylinder Sat Feb 09, 2013 4:19 am » Post: #1 » Download Post I've recently acquired an MC21 that for the past few years sat in the weather without much of its fairing. A large ignition coil puts out about 40 kV, and a small one such as from a lawn mower puts out about 15 kV. If you can't buy the right adapter you can make one out of an old spark plug. Could it be the igniter? Any tips to check/troubleshoot/fix much. Two cylinder Gen III ignition coil is different from all other versions The Gen III ignition coil for two cylinder engines is a single coil with each end connected to a spark plug. i made sure to keep the pos wire on the pos terminal of the coil pack. If not, swap the plug wires (#1 and #2)-don't forget to swap them on the distributor cap as well. Thanks Matt. Went and bought new spark plugs, no difference. Everything else seems fine, have gas, oil level is good, ran machine for 3 hours yesterday and no problems. Coil and HV wire resistance/continuity test for one-cylinder engines The next test checks for a continu-ous path for the spark through the. Spark plug worn, fouled or damaged. The problem was the vacuum line from the purge valve for the fuel vapor canister was cracked in half. Problem was there before spark plug change though. There are two types of coils used on most Harley-Davidsons.