If you look at all the reasons why a car won’t start, it’s really a feat to see them starting all the time and so consistently. There can be so many systems at play but in general to comes down to fuel, spark and air. If one of those are missing then the car just won’t start.
To break it down a no start condition, the first step is to separate from the engine not cranking and the engine cranking. This means that when you try to turn the car on, the engine either makes that “gug gug gug” noise (engine cranking) or not (engine not cranking).
Let’s deal with the easier of the two first.
Engine Not Cranking
If the engine isn’t cranking then it’s usually due to something in the electrical system. Here is an overview of the electrical system that gets the engine moving:
If someone is not right then we can’t get the engine moving fast enough for it to catch fire. Let’s break it down.
If the battery doesn’t have enough voltage then it won’t be able to power the starter to the point where the engine can get going on it’s own. This is usually what happens when it’s super cold outside or if you’ve let the lights or radio run for too long. It can also die due to:
- A loose wire
- Water inside the component evaporated which leads to poor conductivity
- The battery’s workable lifespan as expired
You’ll also know it’s the battery because when you try to turn the car on you’ll just hear one click and that’s it. This means that battery is out because it doesn’t have enough power to keep trying the starter.
To remedy this situation here are your options:
- Find another vehicle and hook it up to your car using battery cables or buy a portable battery booster. If it doesn’t work the first time around, then hook the battery using jumper cables and just wait 10 minutes so it charges.
- If you have a voltmeter, do a load test on the battery and it should read over 12 volts and be climbing.
After you get your car up and running you should get your battery load tested (It should hold 11 volts for 10 seconds) and use a hydrometer to see if any cells are dead. Also if your battery is 4-5 years old then you should replace it so you don’t end up in this situation again. On top of that, if your battery does die then you should replace it because it’ll never be the same.
If you tried the above steps and it’s not working and it’s still clicking, it’s most likely the starter.
If you try to turn the car on and it’s just continuously makes a clicking noise then it’s time to look at your starter.
A starter’s job is to take power from the battery and to set the engine in motion by moving the pistons/crankshaft etc. If the starter isn’t working correctly then it won’t move the engine enough for it to get going on its own.
The method commonly used to determine if the starter is the problem is to connect the positive terminal from the battery (use a cable if you have too) to the post on the starter that attaches to the solenoids. What you’re looking for is the starter to spin when attached – if it doesn’t than you know your problem.
The Starter Solenoid
The purpose of the starter is push the Bendix gear on the end of the starter into the flywheel which turns the engine over. It’s an electromagnet actuated lever that can bad as well. You can hear the solenoid by it’s clicking before it cranks the engine. When you turn the ignition key from off to on, but not start, you should hear 2 clicks from the solenoids.
Broken Timing Belt or Timing Chain
This is probably the worst of them all, especially if you have an interference engine. You would need a mechanic to diagnose this, but a good starting point is look at the records of the vehicle. A timing belt should be changed at around 100,000 to 140,000 km’s so make sure that’s true for your vehicle. For timing chains, they don’t need to be replaced regularly so in that case the problem is usually deeper.
Engine Cranks but Doesn’t Start
In this situation, when you turn the key on the engine tries to start but is unable to because of an issue with air or fuel.
Crank Sensor, Cam Sensor or wiring
You will know that crank or cam sensor has something wrong with it when you plug in the OBDII reader and get a code for it. The crankshaft position sensor measuring the engine’s RPM’s and the position of the crankshaft. If the sensor isn’t working or there is something wrong with it’s wiring then the vehicle won’t start.
A camshaft sensor works very similar to a crankshaft sensor except it measures the position of the camshaft instead of the crankshaft.
If there is no fuel going to the car’s engine then it can’t start. This can be caused from not having enough fuel in the gas tank (always worth a check) to a faulty fuel pump, blown fuel pump fuse, plugged filter or line, bad rely, failed PCM injector driver or injector power supply rely. In some vehicles it can even be caused by the security system.
For these situations, you’ll need a mechanic to find out the exact root cause of the problem as it can multiple issues.
An engine is flooded when excess gasoline floods the spark plugs cause them to foul up and wash the oil away from the pistons rings, reducing compression. This happens when you continuously crank the engine hoping it’ll start but never does.
If this is the case, you should give the car a few hours (4-6) for the excess oil to evaporate. In the future, it’s best to not continuously crank the engine hoping it’ll start because it can also make it difficult for the mechanic to find the root cause of the no start.
Bad Mass Air Flow Sensor
If your car starts but stalls immediately – then there is a chance it could be due to a bad mass air flow sensor (MAF). The MAF is used to measure the amount of air coming in and is relatively easy to replace (in my vehicles).
The above is a good starting point to find out why your vehicle isn’t start – but there can a lot more reasons why and the best way to determine the root cause is through the process of elimination.
We will perform the diagnosis and the repair so you don’t have to worry about towing the vehicle to a shop, which is just a huge hassle.