By Greg Gordie
Automotive design has made no-start situations less prevalent today than thirty years ago. But they still occur and are always frustrating. Making matters worse, the root cause is more difficult to isolate these days because cars are built with computers. Without access to diagnostic equipment, such as an OBD-II trouble code scanner, finding and resolving the issue may be problematic. But it is possible.
In this article, we’ll explore some of the factors that can contribute to a no-start problem. I’ll first explain how your car’s ignition system turns the engine over and then go through a few scenarios to help you uncover the root cause.
An Overview Of Your Ignition System
When you turn your key in the ignition, a current is generated by the battery and sent to the ignition switch. It continues traveling to the starter solenoid, which engages the battery to send another current directly to the starter. The starter is engaged and cranks the engine. Once the engine cranks over, it begins to run and you can release your key. If your vehicle refuses to start, the problem is usually found somewhere in this process. The challenge is narrowing it down.
Is The Battery Drained?
If your engine refuses to crank, you will either hear a series of clicks or silence. In a majority of cases, the cause can be traced to the battery. It may be dry (i.e. out of juice) or weak. Or, the connection between the poles and terminals may be compromised due to accumulated corrosion.
An easy way to test the battery is to turn your cabin light on and try cranking the engine. If you notice the light dimming, your battery is dead or weak. If the light remains bright, the problem likely involves the ignition switch, starter solenoid, or starter.
A Cranking, No-Start Situation
Suppose your engine cranks over when you turn your key, but refuses to fire (i.e. roar to life). At the very least, this means the battery is producing sufficient voltage to engage the starter. So, the battery and starter can be ruled out as possible causes. Because the initial current must travel through the ignition switch and starter solenoid, these parts can also be ruled out. In nearly every case where the engine cranks, but does not fire, the problem involves insufficient fuel, spark, or compression.
Checking For Fuel, Spark, And Compression
In order for gas to travel from your gas tank to your engine’s cylinders, sufficient pressure must be generated by the fuel pump. If you lift the hood of your car and have a friend turn your key in the ignition, you should be able to hear the pump working. If you are unable to hear it, there’s a good chance it has failed. You can verify this with a fuel pressure gauge.
For your engine to operate, the cylinders’ spark plugs must generate a sufficient spark. The easiest way to verify whether this is happening is to use a spark tester. It’s simple to use. By holding it against the plug wire while someone cranks the engine, you can validate the spark and determine its strength.
If there is sufficient fuel pressure and spark, the problem is with the level of compression in the cylinders. Compression is necessary for the spark plug to ignite the air-fuel blend. If it is lacking, it can cause a no-start situation. You can test whether the cylinders have adequate compression by using a stock compression tester. One end is inserted into the spark plug hole (the spark plug must be removed first, of course) and the compression reading is reflected on a gauge.
If compression is low in a single cylinder, the problem is likely due to a faulty exhaust valve. If it is low in all of your cylinders, it may be due to a faulty timing belt.
No-start automotive problems are challenging to diagnose without the help of a few diagnostic tools. But with a methodical approach, you can successfully narrow down the culprit.
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Topics: Automotive | Comments Off
MLA Style Citation:
Gordie, Greg "Troubleshooting A Car That Won’t Start." Troubleshooting A Car That Won’t Start. 2 Jul. 2010. uberarticles.com. 12 Sep 2014 <http://uberarticles.com/automotive/troubleshooting-a-car-that-wont-start/>.
APA Style Citation:
Gordie, G (2010, July 2). Troubleshooting A Car That Won’t Start. Retrieved September 12, 2014, from http://uberarticles.com/automotive/troubleshooting-a-car-that-wont-start/
Chicago Style Citation:
Gordie, Greg "Troubleshooting A Car That Won’t Start" uberarticles.com. http://uberarticles.com/automotive/troubleshooting-a-car-that-wont-start/
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