Why is my car not starting

What's your Year, make, and model? Always provide this when it's a car question.

Have you tried checking:

• fuses relays
• The open cricut voltage of your battery (state of charge testmakeske sure it reads at LEAST 12.8 volts DC - 13.2 (some AGM feels fresh off the charger may read as high as 14vd. Let a battery rest for 5-10 minutes before measuring the state of charge voltage.
• Starter coil
• Air filter
• Starter motor
• Key programming if applicable (only if new keys have been recently made or programmed for cars ~ 2012 or newer)
• Fuel pump and injectors
• Spark plugs.
• Also, check the electrical system for a parasitic drain.
• Have a professional test the starting battery or use a CCA meter or carbon rod load tester (you will need to recharge the battery with an external charge after using a true load tester.
• If you aren't sure what an item is or how to test it I'd recommend a professional auto mechanic

After checking for air fuel and spark, the tirst thing I usually check is the battery, but with a new one (as long as the manufacture date is within a few months), it's probably fine, so I'd skip over that. That said, check the starter fuses and relays - they rarely fail, unlike pyrofuses (which are designed to blow in a crash), but it's worth a shot if all else fails. If you want to check for corrosion, it will not hurt, but it stands out as it is green and is obvious. If you can quickly check the fuel filter without a major teardown, then it's a reasonably quick checkpoint as well.

The test I usually do on a non start car (except for the Northstar V8s or a handful of older Lexus engines, which also do it; those are a PITA to do, you bite the bullet and buy a starter and "parts cannon" it for your sanity) is I will whack the starter with a rubber mallet. If it starts with a mallet hit, the starter needs to be replaced ASAP, as it is failing. It's only meant to confirm the symptom, and not buy time. It will fail to the point where you can't hit it and get it going.

If that doesn't help (or the starter is buried in the engine bay making the whack test impractical), pull all of the spark plugs and check for oil fouling and possible engine coolant/oil mix issues. The issue now is that if you see this, you may need a new head gasket, provided the engine isn't damaged. The problem is that if you continue driving with that issue and it fails, you've likely damaged the engine so that means you may be looking at a new motor. While you do that, if you have a DMM and know the resistance values of the ignition coils, as one marginal coil can take out the engine until it's replaced. This is how the meter should be set (ignore the screen, I used a resistor on my desk to show; the exact value will be in the Mitsbishi SM):

As a bonus (if you can), have the right wrench and socket on hand (or can quickly get it), and locate the center bolt that holds the crankshaft. Do 2-3 partial turns and see if it moves. If it doesn't, the engine is seized. This is really more so when you THINK you have a bad engine, don't do this unless all else fails, as you need to find the factory SM and see which way the pistons turn and do it the same way as the engine naturally turns it - some rotate left, some rotate right.