What To Do When Your Car Cranks But Won’t Start
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An average car dies many deaths, but with the right owner, it can always live to drive another day. When something fails, a DIY diagnosis and fix can save money and eliminate the inconveniences of dropping the vehicle off at the shop. One of the most common encounters involves a car that cranks but won’t start. Don’t worry, you’ve got this.
With a broad no-start issue, the possible causes are plenty, so it’s important to understand what it takes to make a car start and run. A normal gas engine needs power, fuel, air, compression, and spark. As indicated by the car cranking, power is not an issue, so it’s likely an issue with spark, fuel, or compression. See, you’re already making progress!
Through the process of elimination, we can determine what system and what part is causing a blockage in the path to combustion. The Drive’s die-hard informational team is here to guide your voyage and help along the way.
Potential Sources of the Problem
Somewhere on this car, there’s a failure within the fuses, relays, ignition system, fuel supply, or compression. A quick and dirty method of finding issues is using an OBD2 scanner to check the vehicle for codes, but if it’s clear, there’s some work ahead. Let’s figure this out.
Fuses and Relays
- Locate the fuse box and identify the fuses and relays related to the ignition system and fuel system. There should be an identification diagram on the fuse box or on the backside of its cover.
- Using a test light, inspect and test for blown fuses.
Ignition System and Spark Plugs
The ignition system consists of spark plugs, spark plug wires, a distributor (when present), an ignition coil or coil pack, and the ignition control module. Here’s how to narrow it down:
Spark Plugs and Wires:
- Check the spark plugs for damage or bad gapping and replace accordingly.
- Use a test light to check the spark plug wires for continuity.
- If yes, it is doubtful the ignition system is the issue. Move on to fuel and compression.
- If no, the problem could lie in the spark plug cables, the distributor (if you have one), or the ignition coil.
Distributor and Ignition Coil:
Most modern cars do not have distributors. Instead, each plug wire has its own coil. Sometimes the coil is attached to the plug wire, other times, they are located in a block called a coil pack. Use these steps to inspect the distributor, ignition coil, and/or coil pack.
- To confirm an issue with the distributor, you need to check the ignition coil for spark.
- If the ignition coil has spark, there must be a problem with the distributor or the wiring between the ignition coil, distributor, and spark plugs. Replace all three.
- If the ignition coil does not have spark, it’s time to check its wires.
- Use a test light to check the continuity on the signal wire and power wire on the ignition coil. If both wires are functional but the coil fails to produce spark, the ignition coil or the ignition control module is bad. Check both and replace as necessary.
- If the ignition coil power wire is not getting the correct voltage, follow it back and test any possible sources of disconnection or interference.
- Next, test the crankshaft position sensor. This little piece of tech reads the motion of the crankshaft and sends signals to the ignition system when to fire.
A quick method to check if there’s an issue with the fuel supply is to spray starter fluid into the air intake hose. If the car then starts, runs for a few seconds, then dies, the system is not getting a proper amount of fuel. This means there could be a problem with the fuel pump, fuel filter, or fuel injectors.
First, check the fuel pressure with a fuel pressure gauge. If there is no pressure, you likely have an issue involving the fuel pump. If the system shows low pressure, it might be the fuel pump or a clogged fuel filter.
Follow The Drive’s guide to diagnosing a bad fuel pump.
Follow The Drive’s guide to diagnosing and replacing a clogged fuel filter.
- Use a multimeter to check the connectors on the fuel injectors. If the voltage isn’t measuring up, there is an issue with the connectors or the wiring.
- If you’re still having issues, check the crankshaft position sensor, the camshaft position sensor, or the throttle position sensor.
- If you believe the injectors might be clogged, follow The Drive’s guide for how to clean fuel injectors.
If everything above has failed to diagnose the issue, use a compression tester to test the compression of your engine. Low or no compression could prevent the car from starting. If you find you have low or no compression, you might have a major mechanical issue with the engine and should consult a professional.
Get Help With Car Cranks From a Mechanic On JustAnswer
The Drive recognizes that while our How-To guides are detailed and easily followed, a rusty bolt, an engine component not in the correct position, or oil leaking everywhere can derail a project. That’s why we’ve partnered with JustAnswer, which connects you to certified mechanics around the globe, to get you through even the toughest jobs.
So if you have a question or are stuck, click here and talk to a mechanic near you.
FAQs About a Car Cranking But Won’t Start
You’ve got questions, The Drive has answers!
Can Bad Spark Plugs Cause a Car To Crank But Not Start?
If the spark plugs are old, worn, fouled, or damaged, they might not spark. When there’s no spark, there’s no starting.
What Can Cause a No-Crank, No-Start Situation?
If your car does not start and does not crank, there’s likely an issue with the starter or the charging system, which includes the battery, the battery terminals, the alternator, and any wire connections.
Will a Camshaft Sensor Cause a No-Start Issue?
It is rare for a camshaft sensor to be the root cause of a no-start situation, but it’s possible.
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