Why Does an Engine Stall?

engine receiving service

Why does my car stall when I stop?

When we put off doing our taxes until April 15th, that is stalling the inevitable. When we’re talking about cars though, what is stalling? That type of stalling is an engine stall. So, why would an engine stall, is that rare? Unfortunately, an engine stall isn’t that rare and there are number of causes for engine stalls, which is what we’re going to discuss here. 

A car that stalls when stopped could be from any of the air flow, fuel flow, or the ignition. 

  • If the computer or the engine are getting incorrect air readings, it result in an engine stall. In most cases, it will start back up.  
  • If the fuel pump isn’t getting enough fuel pressure because of the fuel filter is blocked, it can cause an engine stall at a stop or while idling. In this case, it may not start right back  up and if it does, it will have a rough idle. 
  • If the fuel injectors aren’t sending the signals to the camshaft or crankshaft position sensors that sends fuel to the cylinder, it may cause engine stall. 
  • If the spark plugs aren’t getting the message to fire, it can cause an engine stall. 

What causes an engine to stall at idle?

For a car engine to sustain at an idle, there can’t be any issues with any part of the engine, everything must be in flawless working order. Even one sensor being off kilter can create a chain reaction that results in an engine stall at an idle. 

One common cause for engine stall at an idle is a vacuum line in a rubber or plastic hose under the hood. These carry air from the intake manifold to the engine and if they have a crack or hole, you’ll get an idle engine stall. 

Another cause can be with the induction system, like the idle air control actuator valve. The IAC valve directs and meters the right amount of air the engine need to run properly. If the IAC valve is clogged up, it can’t do its job of getting the right amount of air to the engine, stalling is the result. 

Other issues that can cause an idling engine stall includes:

  • Water in the fuel tank
  • Camshaft or Crankshaft position sensor
  • Bad ignition coil
  • A wiring problem
  • Dirty or bad spark plugs 

Another possible cause of an engine stall with an automatic transmission car is the torque converter. An automatic transmission is a complex component of a car and within it are more complex components. The torque converter manages the transmission fluid which is needed to keep an engine running while driving or at an idle. 

When the torque converter is malfunctioning, you’re going to experience an engine stall while idling. The problem could as simple as low on transmission fluid or an overheated transmission. Either way, it need professional mechanic attention. 

What should I do if my engine stalls?

The first thing at all times is the safety of you and your passengers. An engine stall is a scary thing but keeping your head level and in focus so that everyone is safe needs to be first and foremost. 

If the engine stalls while you’re going down the road, you’ll notice the power steering stops and the brakes are all but gone. You need to gradually steer the car to a safe place off the road while applying the brake, then engage the hazard lights. Once you’re in a safe place, try to restart the car.

If you are stopped and idling when the engine stalls, moving off the road to a safe place may not be possible. In this case, turn the hazard lights on and call either your roadside assistance service or the police for help. Do not get out of the car when there is traffic passing by. 

 Is stalling bad for the engine?

For you, it can be a scary, yet humbling experience to have an engine stall. For your car though, there isn’t much chance that it is something drastic in most cases. What can damage your car after an engine stall is trying to save the situation by overcompensating by pushing on the  accelerator or clutch. This usually results in violent bucking and that does put stress on the motor mounts and transmission mounts.

engine fully repaired

What causes rough idle and stalling?

There isn’t just one thing that can cause a rough idling or engine stall.  Some common reasons that cause this to happen are: 

  • Dirty Fuel Injectors
  • Wrong Idle Speed
  • Vacuum Leak
  • Spark Plugs Damaged or Installed Wrong
  • Clogged or Defective Fuel Pump
  • Fuel Filter Clogged
  • Failing Electrical Components
  • Defective Airflow Sensor
  • Oxygen Sensor Dirty

When you have any type of engine stall, while driving down the road or at an idle, you need to take it to a mechanic that knows how to fix a stalled engine. They will have the experience, knowledge, and tools to get your car back on the road again, and it will have a warranty on the work should the problem happen again. Call 630-932-4427 today!