Why wont my car start?
Engine cranking over and not starting? Engine not even cranking over at all? Why wont my car start? All of these are very good questions and it can be very frustrating at times when your engine is not starting. There are a few different kind of no start conditions and we are going to take a very close look at just about each type of no start condition. When your engine wont start, it will fall into one of two different categories. The engine could be cranking over and not starting or it may not even be cranking over at all. It is important to understand the difference between the two.
Engine not cranking over
Lets start by taking a look at a no crank condition. This is where the starter does not even turn the engine over at all when turning the key to the “crank” position. If you are not sure if your engine is cranking over or not, pop the hood and watch the serpentine belt or belts under the hood while someone turns to the key to the crank position. If the belt(s) are not rotating when the key is turned to the “crank” position then your engine is not cranking over. If this is the case, you will need to use a voltmeter to run some tests. Here is one for under 30 bucks. Most vehicles today use a 12 volt battery to provide the starter with enough cranking amps to crank the engine over in all type of weather conditions. If you are experiencing a no crank condition, the battery is going to be the first thing to check. Be sure that the battery has a full charge on it and that the battery voltage does not drop below 9.6 volts when turning the key to the crank position. (you may need an assistant to help you do this). If the battery drops below 9.6 volts when cranking the engine over, either the battery needs to be charged or the battery is bad and needs to be replaced.
If the battery checks out, then we move to the starter and connections. We want to run this same test at the starter on both terminals. Be sure that both terminals on the starter have FULL battery voltage with the key in the “crank” position. If so, chances are the starter is bad and will need to be replaced. If the battery checks out and there is low voltage to the starter, then you could just have a bad connection between the battery and starter. If the starter does not have any voltage on the smaller terminal when turning the key to the crank position, then you could have a starting circuit or wiring issue going on causing this condition. Sometimes a bad neutral safety switch or a clutch pedal position switch can prevent the starter from getting battery voltage when the key is turned to the crank position.
Engine is cranking over but not starting
If your engine is cranking over and not starting, then there is a few other things that need to be taken into consideration. There are three things that are needed for the engine to start and run. The big three are Spark, fuel and compression. The internal combustion engine should have no problem running once all three of these are in place. Sometimes the air fuel ratio will be off preventing combustion from within the cylinders which can cause a no start. If the engine is cranking over and not starting, the engine could be flooded or maybe there is gas but just not enough gas to get it to fire up. This is especially true when starting an engine in cold weather. The engine needs LOTS of fuel to get going and to fire up during a cold start in the middle of winter. Another thing is ignition or a valve timing issue. If spark fuel and compression are all present and the engine still wont start, your ignition or valve timing could be off. You can check this my disconnecting power from the fuel pump by removing the fuse or even unplugging the injectors and see if the engine runs on starting fluid. Just spray starting fluid into the intake while someone cranks the engine over. If the ignition and valve timing are close (if not perfect) the engine should start and run. If this is the case, chances are you just have a delivery concern. Another thing that is overlooked is checking injector pulse. If there is plenty of fuel pressure, you are going to want to see if there is injector pulse when cranking the engine over. This is done with a tool called a noid light. This tool plugs into the injector connector and should blink when cranking the engine over. This means that the computer is pulsing the fuel injectors open to allow fuel into the combustion chamber. There are several different styles of fuel injectors. This means there are a few different styles of noid lights. Here is a good noid light set that has all different style noid lights for only 30 bucks.