A faulty idler pulley can be the reason behind rough idling. The pulley and serpentine belt are responsible for transmitting power to certain components including the alternator. If the idler pulley is not functioning properly, the alternator doesn’t recharge the battery enough so it doesn’t have enough energy to run the ignition.

What happens when idler pulley goes bad?

A broken or seized pulley can quickly lead to a torn belt, or in less serious cases, the belt falling off of the engine. An engine without a belt can quickly run into issues such as overheating and stalling, as it's the drive belt that allows the engine accessories to function.

Does the serpentine belt affect the battery?

A broken serpentine belt stops the alternator from generating power to operate the vehicle's electric (and electronic) systems and recharge the battery. The headlights will dim, the radio will not work, and the battery will go dead!

Can a bad belt tensioner cause battery problems?

Battery Issues

If the battery light goes on and off during the start up of the car or while driving, this can be a sign that the tensioner is weakening. A normal tensioner speeds the belt enough to keep the alternator on, powering the car battery. The car battery light will go on when this happens.

Related Question Can a bad idler pulley cause battery problems?

What are the signs of a bad idler pulley?

Signs and Symptoms of a Bad Idler Pulley

  • Chattering, Squealing, or Chirping Sound.
  • Corroded Surface.
  • Excessively Loose Idler Pulley.
  • A Bad Idler Pulley May Spin Excessively.
  • Slow to No Spin or Binding.
  • Can a loose alternator belt cause the battery light to come on?

    A failing alternator belt can cause the Battery Light to turn on, dimming or flickering lights in the car, and engine stalls.

    Can a tight serpentine belt cause loss of power?

    A broken serpentine belt will immediately lead to a loss of power assist for the steering system. For obvious reasons, this can be detrimental if your car is in motion.

    How do I know if its my alternator or alternator belt?

  • Battery light is on. When the battery light on your instrument cluster comes on, you will need to pay attention.
  • Dimming or flickering interior lights. The lights on the inside of your car are used primarily during the nighttime hours.
  • Engine stalls.
  • What problems can a bad tensioner pulley cause?

    If the drive belt tensioner pulley has any sort of issue it can cause unusual and accelerated wear on the belt. A bad pulley can cause fraying on the edges of the belt, and in severe cases can even cause it to break. Other symptoms of a bad belt tensioner is failure of the belt driven accessories.

    Can a bad belt tensioner cause the alternator to go bad?

    A bad belt tensioner can also lead to the alternator failing to function as designed. The engine's alternator is meant to power the automobile's electrical system and also charge the battery while the vehicle is operating.

    How do you know which pulley is bad?

  • Squealing. When the engine is idling, a bad pulley may make a squealing sound.
  • Frozen. The bearings in a pulley may cause the pulley to freeze or in some cases hard to spin.
  • Belt Travel.
  • Pulley Mounting.
  • What happens if tensioner pulley breaks?

    When the tensioner or tensioner pulley fails, the loss of tension can cause the belt and pulleys to make high-pitched rattling or chirping noises. If the pulley bearing completely fails, it can also cause a squealing or even a grinding noise. Symptom 2: Knocking or slapping. This can cause a slapping or knocking noise.

    What does an idler pulley do?

    The idler pulley is a common part that's found on the majority of the vehicles on the road. Its primary function is to provide tension and guide the engine drive belt. These belts wrap around the various parts of the engine such as the power steering pump, alternator, water pump etc

    What is overrunning alternator pulley?

    The overrunning alternator pulley is a further development of the fixed belt pulley on the alternator. Thanks to its overrunning clutch, it damps the vibrations which are generated by cyclic irregularities in the crankshaft and also enables the engine speed to be reduced rapidly in the event of sudden load changes.

    Can timing chain tensioner cause misfire?

    Hi there - yes, a worn or stretched timing chain, weak timing chain tensioner, or worn timing chain guides can cause misfiring, cam timing problem codes, low power and generally poor running of the engine. That would result in major engine damage.

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