Dan Ferrell writes on auto maintenance and repair on his own account. It has certifications in automation and control technology.
Why won’t my car start?
When your engine starts but won’t start or run, it could mean your engine is having trouble producing a spark, getting fuel, or generating compression. The most common causes are problems with the ignition (for example, a bad ignition coil) or the fuel system (for example, a clogged fuel filter). However, the source can also be a mechanical failure (for example, a leaking valve) or faulty components in other systems.
What “crank-no-start” not it generally means there is a problem with the starter motor. If the motor turns normally, you don’t have any starting problems.
If it doesn’t start properly (the engine turns slowly or won’t turn, or you hear strange noises or nothing when you try to start the engine), check out this other handy guide to troubleshooting the starting system.
Whatever you do, avoid repeatedly starting the engine in the hope that it will start. It can drain battery power and damage the starter in the process. Instead, try using the charge left in your battery to locate the fault. In this article, I offer the following:
- Rapid diagnostic tests
- Do you have a spark?
- Is fuel getting into the cylinders?
- Do you have adequate compression?
- Other possible components that can cause a no-start condition
This guide will give you first six quick things you can check, and then three systems to troubleshoot (spark, fuel, compression) using some quick and simple diagnostics. Then, for more help, you will see a list of components on related systems that can be associated with a no-boot condition.
1. Six Quick Checks (check these first)
When trying to figure out why your car doesn’t want to start, consider these possibilities.
For example, make sure there is actually fuel in the tank.
Scan computer memory
The computer in modern vehicles monitors and controls a large number of sensors and actuators. Scan your computer’s memory for trouble codes before doing anything else. Even if the check engine light hasn’t come on, you might find a pending code that can guide you in your diagnosis. False input or missing input from sensors like the Crankshaft Position Sensor (CKP) or Camshaft Position Sensor (CPS) can prevent the engine from starting. Also, a faulty throttle position sensor (TPS) can cut the spark from the cylinders.
If the engine runs slowly, you may have a discharged battery, loose or corroded battery terminals, or starter cables.
Problems with the starter motor or circuit can prevent the motor from starting. You may want to check the circuit for voltage drop or have the starter checked. Pay particular attention to unusual noise when starting.
Many modern vehicles are equipped with an engine immobilizer as an anti-theft security system. The cars security system You may have made a mistake that disabled the fuel or the ignition system or the chip in the key may have failed. To troubleshoot a built-in security system, check your car’s owner’s manual or check with the store that installed your alarm system.
Check for a blow fuse That may be preventing a circuit from working properly, such as the fuel injection or the computer system.
2. Do you have Spark?
First, you need to check that a good spark is reaching the cylinders. You can do this test without a spark tester, but it’s best to use one because a weak spark and a missing spark can prevent your engine from starting. If possible, use an adjustable tester so that you can test 40KV, 30KV and 10KV sparks.
- Select an easily accessible spark plug and unplug the spark plug wire, the plug wire …