It happens to everyone you go out to your car in the morning ready to go to work and the car won’t start. It was running fine the previous day or just hours before but now it won’t start.
We will try to step through some of the most basic things that you can check in a few minutes to see if you can get your car running or if you need a mechanic’s help.
First thing you have to figure out is if the battery is fully charged. If you have a multimeter turn it to the 12volt test and check across the battery by placing the probes directly on the terminals of the battery not on the battery cables. Your fully charged battery should read about 13volts. If it shows less than 12 volts then it is not fully charged. This could be a problem with the battery or that the battery just needs charging. You will need to charge your battery or jump start it.
Testing for an operational fuel pump is the next quick thing to check. Turn your ignition key to the on position and you should hear a quiet hum for about 10 seconds. This is your fuel pump charging your fuel system with pressure. If you can’t hear the fuel pump then you can open your fuel cap and have someone turn the key from the off to the on position and listen for the hum. Again it is very quiet and if you haven’t noticed what it sounds like before then try this on an operational car to listen for the hum of the fuel pump.
If you have power and your fuel pump is charging then double check that you have fuel in your tank by reading the gauge. Yes its not likely but check anyway.
Turn the key to the start position. Does your engine’s starter run and crank the engine? If your engine’s starter does not operate and you have a good charge to the battery you could have a bad starter or starter relay. A bad fuse is also a possibility. To test this you would have to connect a jumper cable to the positive terminal on your starter and the other side to the battery positive terminal and the starter should run. Only do this for a second.
Another thing that might stop your starter from engaging is a bad neutral lockout safety switch. If you have a manual transmission then you can wiggle the stick shift while depressing the clutch just to make sure that your neutral switch is working. If you have an automatic then you can try shifting to the N neutral setting to see if your neutral switch is not malfunctioning. If your car isn’t in neutral it won’t start. Its rare but that switch can fail.
If the engine cranks/tries to start but doesn’t then you have to find out if you are getting spark to the spark plugs and fuel to your injectors.
The easiest way to figure out if you have a spark or fuel problem is to use starting fluid. Starting fluid comes in an aerosol can and is sprayed into the carburetor or throttle body opening of your engine. It is a strong mixture of different chemicals that act like the gasoline supply to your engine. To use it you will have to remove the air filter setup for your engine and then you spray it for about 3 seconds and try to start the car immediately. Its good to have two people doing this so the starting fluid won’t evaporate before you can get to your key and turn it.
If the engine attempts to run or runs for a few seconds and dies then you know your ignition system is sending electricity to your spark plugs and you have a fuel system problem. If the engine does not start then you can attempt to spray for another three seconds and then try starting again. If you are sure you have a good amount of starting fluid in your system then the problem is with your ignition system and spark to the spark plugs.
The next thing that you can quickly test for is a broken timing belt. On most engines if you remove the oil fill cap that is on the valve cover of the engine you can look inside and see the internal workings of the engine head. You might see valve springs, push rods or an overhead camshaft but you will be able to see a moving part. If your timing belt has broke then when you attempt to start your engine the parts you see through the oil fill cap won’t move. If you see moving parts when you start the car and the engine rotates then you know that the timing belt is in one piece. It is possible sometimes that the timing belt will slip but this is somewhat rare. If it does your engine may or may not still be able to attempt starting. If it is broken then it will not start and it is possible that you have internal engine damage from your valves hitting your pistons.
At this point it is a good idea if you haven’t already to test your engine’s computer diagnostics with an ODBII Tester to see if there are any error codes that are helpful. There might be or there might not be codes available to read in the storage of your computer memory. Also sometimes it is difficult to use those codes because a code can be generated when another system fails. You will still be at an advantage to try testing and reading the codes.
Sensors are what return codes to your computer. Problems with sensors normally will not stop your engine from attempting to run but a bad sensor can make your engine run poorly and die quickly after it starts.
Ignition Systems that have multiple coils normally won’t stop an engine from running if there is only one bad coil. It is also highly unlikely that more than one coil will die at a time. A four cylinder engine will attempt to run even if two coils and maybe three coils are bad but it will run really poorly and the engine will normally shake. An older system that has a single coil that distributes spark to all of the spark plugs can die if the coil is bad. To test for this the easiest way is to attach a timing light to the spark plug wires and watch for the timing light to blink. You can also pull a plug and wire from the engine and allow the threaded part of the spark plug to touch ground on your engine and you should see a spark across the gap of the plug.
If you have a multi-port fuel injection system then a single bad fuel injector normally won’t stop your engine from running but it will probably run poorly. Injectors normally do not all go bad at one time however if there is some type of contaminant in the fuel system it could block all of your injectors.
Clogged Fuel Filters can stop fuel from getting to your injectors or carburetor. I have experienced a clogged fuel filter that stops the engine from running however the engine also died while the car was driving down the road. If you have a fuel filter that is so clogged that it won’t let your engine run normally you will have really bad performance and it will die while running prior to it completely clogging. However if you just got some bad gasoline it is possible. Additionally if you have moisture in your fuel system it could freeze in the line.
Problems with your fuel system can be diagnosed by using the starting fluid test. If your engine runs when you use starting fluid but won’t run without it then you have a fuel system problem. This can begin with contaminated gas, then your fuel filter and then your injectors or carburetor being clogged or malfunctioning.
Electrical and Ignition problems can also be caused by Fuses and Relays being broke or burnt out. On most vehicles the primary fuses are located under the drivers side dashboard. There are additional fuses and relays that are under the hood. Fuses can normally be tested visually or with a test light but relays are a little harder to diagnose. When a relay is operating it will normally click because there is a switch inside it that is turning on. Such as your fuel pump relay that is getting a signal from your ignition and then sending power to your fuel pump to prime your fuel system. You can also test them with a multimeter if you have the specifications for testing them.
Final Note
Diagnosing why your vehicle isn’t starting can be relatively easy. All engines rely on two things. Fuel to the combustion chamber and then spark from a spark plug igniting that fuel.
This is why the Starting Fluid Test is a really quick way to figure out which system is the problem.
If your car attempts to run when you spray starting fluid in the throttle body then you know you have a fuel system delivery problem. If it doesn’t start then you know you have an electrical system ignition problem.
Tracking the problem down after you know which direction to look is not that difficult. Just follow proper order and trace the problem back to its source.
Having a good repair manual and a basic set of tools really helps in this situation and can save you hundreds of dollars at a mechanic.