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Ignition Troubleshooting Tips

Help customers avoid some of the most common ignition problems with these helpful tips from suppliers.

By Virginia DeMoss


A faulty ignition system can quickly wreak havoc on a race team’s momentum during an event. With that in mind, we asked manufacturers of ignition components about some of the common mistakes racers make regarding these products, and how to avoid or resolve those issues.

“Bar none, the absolute most common ignition system problem is insufficient ground,” stated Terry Johnson at Crane Cams, Daytona Beach, Florida. “The ignition ground needs at least a 12-gauge wire and it needs to go to a bare metal part of the frame of the car. From there, problems are normally caused by simple things like poor or degraded crimp connections,” he said.

On its website, Crane has a short, informative sheet called “Common Ignition Information” (click on Tech Info, then Tech Tips), which outlines all of the common issues racers may overlook.

“Grounds are one of the most important things on a race car, especially as more electronics are used,” agreed Silver Gomez at MSD Performance, El Paso, Texas. “Battery supply voltage is another issue we see as electric fuel pumps, water pumps, fans and more sap power through a race.

“Another issue to consider, especially as boost pressure and compression ratios increase, is spark plug gap,” Gomez continued. “If you are experiencing a top-end miss or breaking up under load, we recommend that you drop the plug gap by .005 inches and test again. Many people run huge gaps, but when the engine is under heavy loads, that gap may just be too large. This is also when you need to look at your ignition coil selection to make sure you have the best coil for your engine’s needs and ignition.”

“When resolving CD ignition problems, we generally ask people to check and make sure they have battery voltage and ignition switch voltage,” offered Dave Telling of ACCEL, Cleveland, Ohio. “We also recommend checking voltages when cranking, to make sure that supply voltage is good under that condition. Make sure your battery and cables are in good shape. Old batteries lose capacity, and when the engine starter is engaged, it can cause the battery voltage to drop down low enough that the ignition doesn’t work. Another problem is damaged or marginal wiring, especially in older vehicles. Ignition switches and solenoids can wear out over time, and this may result in a no-connection or intermittent situation.”

Telling pointed to several other ignition problems that retailers can help prevent, including installation errors and mismatched components. “Over the years, we’ve had situations where customers misidentified wire colors, connected battery wires backwards, or threw away the instructions,” he said. “We’ve tried to identify possible problem areas and incorporate ways of compensating. For example, our latest CD ignition designs have reverse battery protection built in, so if you hook the battery wires up backwards, the system doesn’t blow up parts, it just doesn’t activate. Once the wiring is corrected, everything works as it should.”

“When wiring up a new installation, it’s critical that the retailer stress the importance of following the wire diagram,” said Lawson Mollica at AEM, Hawthorne, California. “It seems simple enough, but I know most of us are guilty of diving into something, hitting a snag, and then looking at the instructions. You may have to start over because you’re on step nine and you skipped something in step three. Worse, you think you have it all put together, you fire it up, and something bad happens.”

“Sometimes guys try to run their wires too long,” suggested Brock Robertson at BR Motorsports, Visalia, California. “There is a lot of current going through ignition wires, spark plug wires, so they tend to break down and need to be replaced on a routine basis,” he said. “As far as the magnetos, keeping them clean and dry is a big thing. A lot of times they’ll put a scrub bag over the magneto to keep the water out when they wash the car. But the moisture condenses in there and they don’t take the cap off and let the magneto dry out inside. When the magnets and the induction coil get rust on them internally, it really robs power.”

“Most racers and mechanics need to learn how to take spark plug wires on and off,” stressed Brian Scott of Scott Performance Wire, Mooresville, North Carolina. “In and of itself, if the wire is routed properly and tied up, spark plug wires just don’t go bad. They go bad because of abuse like grabbing and yanking them, which tends to loosen the connection, instead of reaching in and grasping the boot.”

Martin Uhlir at Brisk USA, Humble, Texas, said the two biggest issues surrounding spark plugs are selecting the wrong plug for the application and improper installation. “By matching the ignition system and spark plugs for the given application, you can easily gain horsepower by getting the most efficient ignition,” he said. “Aside from that, most people underestimate the importance of installing spark plugs correctly and properly torquing them down.”



Ignition Troubleshooting Tips

Performance Racing Industry