Skip the auto shop - Our mechanics make house calls

Q: Spark Plugs spark once

asked by on

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car makes a "humming" noise when I try to start it

Hello. If you were to tap anywhere, it would probably be the starter solenoid, which has the main power wire attached to it, although it is not likely that tapping the starter solenoid will start the car. It sounds...

Q: My car is idling rough

It is a possibility that the engine performance issues may have been caused by a problem when it putting the pieces back together, however, the trouble codes seem to point to different issues. Both codes are related to the oxygen...

Q: Idle Problem/Engine Misfire Code P0300 P0301 P0303

Hi there. Check the spark plugs and fuel injectors for cylinder 1 and cylinder 3. Both cylinders are misfiring. If the plugs are good and the fuel injectors are firing, then there could be a problem with the internals of...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.