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Q: Spark Plugs spark once

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My car suddenly didn't start. It’s been working great and now it won’t start. I've checked the injectors, fuel relay, fuel pump OVP relay, and they are good. The spark plug wires, distributor are new, and I checked the coil and EZL and CPS and they are all good on ohms. The thing that is puzzling is that my spark plugs only spark once. They have a nice bright blue spark, but the cylinders spark only once. One other thing I noticed was that my rpm needle goes up and down between 500 rpm – 1500 rpm when I crank the engine. This happens even though the engine spins at the same rpm. Do you think I have a bad CPS?

Either a failing crankshaft sensor or impulse wheel could be the cause of the fluctuating RPM reading. The crankshaft sensor signal is often used to start both fuel pump operation and start the ignition coils with the camshaft sensor setting the sequential injection and ignition firing order.

You may want to have faults read out of the ECM prior to replacing the crankshaft sensor and look at the crankshaft sensor wheel. If the sensor is mounted on the front of the engine the sensor wheel may be part of the dampener and may have slipped or vibrates. If it is a sensor wheel that is part of the flywheel, a bent tooth may be the cause. To have this resolved, you may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the equipment and expertise to correct this hard starting issue.

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