Crank No Start Diagnosis: The Step-by-Step Guide

It’s easy to take the sound of the starter turning over the engine for granted every time you get behind the wheel. When you turn the key or press the start button but don’t hear that signature chug-chug-chug, you’re likely faced with the common “crank no start” condition. Despite its prevalence, this concern can easily become a complex problem without the proper diagnostic tools or auto repair knowledge.

This step-by-step guide explores the various methods used to diagnose a “crank no start” condition. Topics covered below include evaluating the fuel system, spark, ignition, sensors, and related mechanical components to determine the source of a “crank no start” condition. Refine your diagnostic and repair processes with Identifix Direct-Hit®, a game-changer when it comes to detailed wiring diagrams, vehicle-specific repair data, and technician-tested fixes.

What is a Crank No Start Diagnosis?

A crank no start diagnosis involves troubleshooting the underlying cause of a cranking engine that refuses to start. Multiple conditions and components can cause a crank no start condition, including a locked steering wheel or a lack of air, fuel, or spark necessary for combustion. With so many possibilities to rule out, the crank no start diagnosis can be challenging to address.

Most diagnostic processes require a thorough investigation of the vehicle’s state to determine the root cause of a particular problem. However, a strategic approach serves technicians especially well in a crank no start scenario due to the complex nature of this diagnostic conundrum. When you tally up all the systems and elements required to start your vehicle, you may have a new appreciation for how much it accomplishes in those few seconds it takes to fire up the engine.

Step-by-Step Guide to Diagnosing Crank No Start

Failing to approach investigating the potential cause of a crank no start condition with intention can set you back, creating more work than is necessary. Extracting information from the vehicle, piece by piece, enables you to narrow down the cause without wasting your efforts or time. Use the following guide to determine the cause of your crank no start diagnosis. 

Air Intake Problems

Your car’s engine requires an optimal mix of air and fuel to function efficiently. If the air entering the engine is not properly filtered or metered, those mis-readings cause the engine control module (ECM) to inject the improper amount of fuel—once the engine starts. However, a malfunctioning mass air flow (MAF) sensor or clogged air filter can cause a crank no start condition.

One of the easiest solutions to this problem is to address a clogged air filter. Replace the filter with a new disposable or reusable unit to ensure clean air enters the intake system. Removing and cleaning the MAF sensor can also improve its readings, allowing the engine to crank and start.

Compression and Engine Timing

Internal combustion engines also require compression to ignite the air/fuel mixture based on strategic ignition and valve timing. Investigating the engine’s timing and compression can provide clues as to the cause of a crank no start condition. Compression testing measures the engine’s ability to produce pressure within the cylinder and can reveal a blown head gasket, worn piston rings, or bent or broken valves.

A compression test may not be necessary if a visual inspection of the engine reveals a worn timing belt or chain. These components are responsible for keeping the engine’s timing, but if they slip or fail, they alter the timing and can potentially cause serious internal issues. For example, a worn timing belt that fails can put the valves at risk of breaking or bending.

Electrical and Sensor Issues

The complex electrical systems and sensors necessary to power your vehicle can also prove difficult to diagnose in light of a crank no start condition. Begin with the battery to determine if it’s providing enough power, then the starter to ensure its proper function. Replace one or both if necessary.

Malfunctioning crankshaft and camshaft sensors can also cause an engine not to crank. If these sensors fail, they’ll likely illuminate the check engine light and throw a corresponding code. Replacing these sensors enables the ECM to determine exactly where the crankshaft and camshaft are for proper timing.

The electrical connections that run throughout your vehicle can also hide the cause of a crank no start condition. Without a ground, many electrical components may fail to operate as expected. Shorts that cause a lack of signal transmission can also inhibit these elements from working properly.

Fuel System Issues

When fuel fails to reach the combustion chamber, the engine may refuse to start. Clogged fuel filters, broken fuel pumps, dirty fuel injectors, and air bubbles in the fuel lines can all cause a crank no start condition. Like any other system, multiple issues can exist simultaneously with the fuel system, compounding the crank no start issue.

Replacing defective fuel injectors can help deliver fuel where it’s needed most. Test the fuel pump with a digital multimeter to determine if it’s receiving power and functioning properly. Treat a tank of fuel with fuel injector cleaner to remove deposits that can clog filters and fuel injector nozzles.

Spark and Ignition Problems

Lack of spark and ignition can also cause a crank no start condition. Remove the spark plugs from each cylinder and inspect them, noting any contamination. If plugs are wet, blistered, worn, or black, replace them before diagnosing the issues that correspond to these characteristics.

Test and replace ignition coils that fail to transfer the proper voltage to the spark plugs. The ignition switch in the steering column may also be jammed. If the steering wheel lock is set, gently turn the wheel to the left and right to disable it.

Theft-Deterrent Systems

Despite their safety purposes, theft-deterrent systems can interfere with engine startup. Immobilizing devices can malfunction, mistakenly prohibiting the engine from cranking to prevent the vehicle from being driven away, presumably by a thief. The theft-deterrent system may even put the car in lockout mode to keep it firmly planted wherever it’s parked.

Revolutionizing Systematic Diagnosis and Repair

Getting to the bottom of a “crank no start” condition can feel like solving a complex mathematical problem, but with the right tools at your disposal, it’s simply a matter of determining the root cause by process of elimination. Identifix Direct-Hit offers technicians and DIYers the resources necessary to diagnose and repair a “crank no start” condition systematically and efficiently. Contact us to discover how Identifix’s suite of diagnostic and repair tools can increase your diagnostic and repair effectiveness to boost productivity and efficiency.

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