Ignition Timing

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The car engine is a complex harmony of parts – pistons, rods, valves, pulleys, camshafts, a crankshaft, all moving rapidly inside your engine as you drive down the road. Pistons pump up and down, valves move in and out, rods pull in and out and the crankshank spins. To keep all these parts moving in synchronicity, your car engine has a timing belt or chain. Its job is to make sure the valves are out of the way when that piston barrels toward the engine’s head.


To understand how important it is for your car’s timing to be just right, a little explanation on how your engine works may make it clearer. Engines have 4 cycles and each of these is repeated in each car cylinder.

First, it takes in air and fuel. In new cars, direct injection is utilized and air is sucked through an intake valve while fuel is introduced via an injector.

he second part of the cycle is called a compression stroke. The air-fuel mix is compressed to create heat and volatility.  

  • The third cycle is the ignition or combustion stroke. It is at this point that your car’s spark plugs fire and ignite the air-fuel mix. This causes the piston to be pushed back to the bottom of the cylinder.
  • The final cycle is the exhaust and this is when the exhaust valve open and lets out the burnt up mix. And then the cycle repeats. The timing of the spark is crucial. When it is off-kilter, then your car engine will work against itself.
Timing Belt Repair, car ignitiong timing repair


Your vehicle will tell you when the timing is off. Here are some of the signs:

  • Poor fuel economy,
  • Sluggish acceleration,
  • Hard starting,
  • Backfiring, or
  • “Pinging” or “spark knock” or also referred to as pre-ignition

Too little spark advance will cause low power, bad gas mileage, backfiring, and poor performance. Too much advance will cause hard starting and pre-ignition.

If your car engine’s timing is off, perhaps it is time to have your timing belt checked. Here are signs that the timing belt need to be replaced:

A high pitched sound – As the timing belt wears out, it starts to produce a high-pitched shrieking or whirring sound. As you start up, you should be able to hear this but sometimes, it also becomes apparent while the engine is idling.

Visual damage – If access to the timing belt is possible, you would be able to see signs of wear and tear. If there are spots of oil or coolant on it, it is time for a replacement.

Hard starting – If it takes several attempts for your engine to catch, a worn timing belt may be the cause.  

The usual recommendation is to have the timing belt replaced every 60,000 miles but it varies from one vehicle to another. It is always a good practice to refer back the manual for your car for advice about the mileage. Or, at American Auto Care, through our customer portal, you can check your vehicle service recommendations online. In any case, if you are experiencing one of these issues, you should have your vehicle checked.