Skip the auto shop - Our mechanics make house calls

What Does Ignition Timing Mean?

Spark Plug Arc

Timing – it has a couple of different meanings when applied to your car’s engine. One of the most critical is ignition timing (not to be confused with engine timing). Ignition timing refers to when spark is created during the engine’s cycle. It needs to be just right or you end up losing power, increasing fuel consumption and producing more emissions in your exhaust.

What’s timing all about?

Your engine runs on a controlled series of explosions. Spark plugs create their spark to ignite fuel vapors. This creates combustion. The explosion then pushes down the piston, which turns the camshaft. However, the plug can’t fire at just any time. It needs to be timed correctly with the engine’s motion.

There are four cycles in an automotive engine (thus the name four stroke). These are:

  • Intake
  • Compression
  • Combustion
  • Exhaust

The spark plug must fire at the right point in these cycles to maximize the power created by combustion. The system should fire before the piston hits top dead center (TDC). The increase in pressure from combustion pushes the piston back down (after reaching TDC), and turns the camshaft. The reason that the plugs need to fire before the piston hits TDC is that if it didn’t happen then, by the time combustion actually occurred, the piston would be so far into its downward motion that the force of the combustion would be largely wasted.

Remember: while gas is highly combustible, it doesn’t burn instantaneously. There is always a delay. By firing before the piston hits TDC, your engine is able to account for this delay and maximize the amount of power each time.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Post a question and get free advice from our certified mechanics.

ASK A QUESTION

More related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...


Related questions

Q: I had a bad oil leak and now I hear a spark sound. Do I need a new coil?

If the oil leak has made its way to any spark plug wires or coils and the wires or coils show signs of swelling or cracking then the component must be replaced especially if spark is coming out. The oil...

Q: Truck not starting after engine removal.

There are countless reasons your truck may not start. This is especially true since everything in the engine compartment got disturbed when you took the engine out. If you engine doesn't crank at all, or cranks slowly, suspect a problem...

Q: Stalling & sputtering after rain

The engine spark plugs and spark plug wires on your 2001 Ford Escape are most likely arching to the ground and may need to be replaced. Run the engine with the hood up and listen to see if you hear...