In the quest for efficiency and reliability, engineers have replaced old-fashioned carburettors with sophisticated fuel injection systems in the average automobile. These injectors are designed to "spray" the correct amount of fuel into the combustion chamber at exactly the right moment, to provide the perfect amount of energy to drive the car. In days gone by, the carburettor-fed solution would rely on mechanical settings, and these would need to be corrected at regular intervals by your trusty mechanic. However, even though this magic is controlled by the engine's computer today, it can still go wrong and when it does, you will see certain signs. How can you tell if your injectors need to be addressed?
How It Should Work
For everything to work correctly, the ECU needs to send a signal to the fuel pump to release petrol into each injector according to the cycle of the engine. When everything is working perfectly, a fine mist of petrol is ignited by a spark to push down the piston and turn the crankshaft. Sometimes, however, impurities in the fuel system can build up resistance within each injector and can block some of the holes that deliver the petrol. This will result in inconsistent delivery and a number of different symptoms.
For example, you may find that the car is difficult to start in the morning and even when it does, it will stutter as you try to press the accelerator pedal.
On the other hand, you may notice some very strange behaviour when you're driving down the motorway and begin to accelerate after a period of cruising. Suddenly, the whole car will begin to vibrate, and this is due to an issue within the engine. It's not receiving the right amount of fuel yet it is still trying to turn very quickly, and this lack of raw material during each cycle will lead to a potentially expensive vibration.
Too Much Fuel
Sometimes, the fuel injector valve will fail, and it won't close when called upon to do so. Instead, it will continue to spray fuel and overload the system. You may think that this would cause the car to go faster, but instead it will simply lead to inconsistent operation and more money to pay at the petrol pump.
While all of this is happening it's not unusual for your "check engine light" to illuminate on the dashboard. This is another reminder to take the vehicle into your mechanic, so that they can clean your injectors or swap them out for new fuel injection parts.