Causes Of Hard Starting When Car Is Hot and How To Fix It

Causes of hard starting in cars

Causes of hard starting in carsThe causes of hard starting when your car is hot can be traced to faults with major components in your vehicle.  Some of them may be loose or corroded battery terminal or cable, clogged air filter, engine control system issues, loose or corroded engine ground connection, and faulty fuel system. Consequently, these issues will be expatiated upon.


Blocked air filter

After the engine is heated up, a blocked air filter can amount to a hard starting condition.  In the course of use, debris, dust, and other impurities will clog the flow of air via the filter. This can also cause other performance problems.

Read more: Causes of hard starting in cars

Blocked air filter signs include hard starting, bad acceleration, misfires, low engine power, and increased emissions.


What to examine:

  • Water or oil contamination.
  • Filter part for the defect.
  • Ensure a flashlight can penetrate the filter media.
  • Change the filter in line with the scheduled servicing.
  • For more guidance, consult the repair manual of your car, if necessary. And if you discover you don’t have one, you can purchase one at an affordable price in an auto shop or via the internet.


Corroded Battery Terminals


It is important to keep a check a check on the condition of the vehicle battery as well as the terminals. Visible signs of corroded battery terminals include a start, hard start, faulty electrical components, undercharged battery, and poor starter motor.


Corrosion in the connectors, electrical system, or terminals pose as abrasion to electrical current. You might be able to kick start the engine after a little corrosion, however, as a result of the resistance in the circuit,  the electrical system may rise, leading to difficulty for the electrical parts in the circuit to function. Until it cools off, it might prove hard to restart the engine.


Moreover, since corrosion is difficult to recognize when it disappears in the connectors, you may have to detach the battery terminal.


What to examine:

  • Connect to your computer to a memory saver linked to the cigarette lighter of your car.
  • Server, the negative battery terminal.
  • Server the positive battery terminal.
  • Carefully check both terminals for green or whitish elements around or inside the battery posts.


Removing Corrosion:

In a disposable cup of 8 oz of warm water add a spoon of baking soda. Apply the solution to the terminals and battery posts using a gentle brush.

Rub clean the battery post and terminals using a shop rag.

Read also: 5 Ways to Keep Tyres in Thier Best Condition

Loose or Corroded Engine Ground Connections


The circumstances in which circuits or components operate beneath the hood can cause electrical systems to become corroded, loose, or disconnected.  Corroded or loose engine grounds will in particular lead to all forms of electrical problems if circuit resistance rises effectively. It can significantly affect the starting component of different electrical systems.


Plus, the temperature rise will make the corroded or loose terminal terrible. And in the same manner, with a corroded or loose terminal, it is difficult to diagnose a poor engine ground by staring at it.


Some bad engine grounds signs include no-start issue, unstable behavior of one or more electrical systems, hard to start conditions, automatic transmission crisis, high voltage around actuators, and sensors.

However, you can do a quick voltage drop of your engine grounds by using a digital multimeter. Also to find your engine grounds, you may need the car repair manual.


Vapor Lock


Volatility is one major feature of gasoline fuel. This is necessary for a blended mix with air for great combustion. However, an operation issue termed vapor lock will surface if you allow the duel to vaporize But allowing fuel to vaporize before it gets to the combustion chamber.


When fuel starts to boil down to the carburetor or fuel injection system, a vapor lock may occur.  In this circumstance, bubbles or vapor mix with liquid fuel and obstruct free flow.  More so, Fuel lines position close to a heated engine or under hot weather will add to vapor lock.


Another reason for vapor lock is blocked vent lines. The lines landing from the fuel tank, allows fuel bubbles to leave the tank and gather into a charcoal container. If the valve in the line stays in close placement or vent line clogs, there would be engine operation problems resultant from the bubble mix with the full as it escapes forcefully from the tank.


Other signs of fuel vapor lock may be hard starting, no starting, engine stalling, and lack of engine power.


What to examine:

  • Blocked fuel return line
  • Clogged vent line
  • Touching a heated engine component or Engine line close
  • Be on the lookout or any other situation that may allow the fuel in your system to become overheated.



Leaking Injector or Fuel Pressure Regulator

Although closely associated with vapor lock, FRP (leaking fuel pressure regulator) or fuel injector is a cause of hard warm starts.  Sometimes, the symptoms may be triggered by a fuel pressure dampener.


At the start, a fuel injector or worn FPR may stop leaking by allowing pressure in the fuel line. However, if the fuel lines are heated in a hot climate resulting in a hot engine, there will be adequate space for the fuel to evaporate inside the line leading to a difficult-to-start condition.


Other signs of poor FPR include stalling, misfiring, and hesitation. Also, from a leaking fuel injector, try to start the engine with a plunged cylinder which will take more seconds of extra seconds of cranking.


Using this easy test, you can lookout for a flooded cylinder:


  • After the engine has warmed up, shut it off.
  • Hold on for a minute or two.
  • For uninterrupted air passage into the engine, depress the accelerator pedal fully.
  • Restart the engine.
  • If with the depressed accelerator, the engine starts better, then the issue might be a leaking fuel injector.


To inspect for an FPR leakage:

  • Remove the vacuum line connected to the FPR.
  • If the line smells like gasoline or is soaked, it means the FPR is leaking.
  • Change the FPR
  • Examine the fuel injector or FPR If necessary.



Sometimes, figuring a hard to start a hot engine may require some minutes.  At other times, you may need to probe around systems and major components. To make this task simpler, this article reviews the popular source of problems and how to recognize and be on the lookout for them.

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