Why is My Car Starting Slow? Slow Start Causes and Prevention

Reviewed by

Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on July 14th, 2024

Reading Time: 4 minutes
Summary
  • Struggling to start your car is not only a hassle but also a possible sign of larger car problems.
  • Common reasons behind a slow-starting car include extreme temperatures, a malfunctioning starter motor, poor fuel quality, car battery problems, and wiring issues.
  • The best ways to prevent slow car starts include changing the fuel filter, cleaning the fuel injectors, charging the car battery, and replacing faulty parts.

It’s frustrating when your vehicle struggles to start properly. It can keep you from getting to work on time or staying on top of your schedule. What’s more, a vehicle that’s slow to start is usually a sign of larger problems, such as issues with the wiring or worn and damaged components. Knowing the possible causes will help you nip this problem in the bud.

Why is My Car Slow to Start? Common Causes

If your car is slow to start, it might be due to extreme temperatures, a faulty starter motor, a weak car battery, or wiring issues.

Hot or Cold Temperatures

When the temperature is too high, the fluid inside the battery might evaporate and reduce its electrical output.

When the temperature is too high, the fluid inside the battery might evaporate and reduce its electrical output. This means the starter motor will have a more difficult time powering up, preventing the vehicle from starting quickly.

Meanwhile, if it’s too cold, the battery won’t hold as much charge as usual. Condensation can corrode the battery as well. On top of that, the cold temperatures can make the engine oil thicker. The viscosity would increase friction, making it harder for the starter motor to spin.

Malfunctioning Starter Motor

One of the biggest indicators that a bad starter motor is responsible for a slow-starting car is if the starter makes strange clicking noises when the key is turned.

The sounds could mean that the motor isn’t working as quickly as usual and that power isn’t properly allocated to it. If this happens, it’s time to repair the starter motor or have it replaced.

Poor Fuel Quality

Using low-quality fuel can damage your vehicle’s spark plugs and injectors, making it more difficult for your vehicle to start. Poor quality can clog the fuel line, making it slower to start.

In more severe cases, a clogged fuel line can prevent a vehicle from starting entirely due to the obstruction of fuel.

Car Battery Issues

The more a vehicle is used, the quicker its battery wears out. Because the car battery and alternator are what provides the spark plugs with power, your engine won’t be able to start if either grows weak or runs out of charge.

A battery that ran out of charge is easy to fix. You simply need to recharge it. However, if the battery itself is damaged, then it might be time to replace it. Look for signs of corrosion and damage from overuse.

Wiring Issues

If the wires attached to the starter motors come undone or get damaged in any way, your car might struggle to start. It’s a good idea to inspect the wiring to make sure there are no signs of damage or corrosion.

If the wires are loose, adjust them until they’re secure once more. If the car still struggles to start or starts slowly after ensuring the wiring is in acceptable condition, you might have to consult an expert.

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How to Prevent Slow Car Starts

Dealing with slow-starting cars is stressful. Fortunately, there are ways to keep your car starting efficiently, like changing the fuel filter, cleaning the fuel injectors, ensuring the battery is charged, and replacing faulty parts.

Change the Fuel Filter

It’s a good practice to replace your vehicle’s fuel filter at least once every two years.

The fuel filter prevents impurities and other contaminants from reaching the engine. Unfortunately, it could get clogged over time, especially if you use low-quality oil.

By replacing the fuel filter before it gets clogged, you can prevent slow car starts brought about by increased fuel pressure.

Clean Your Fuel Injectors

Cleaning and unclogging your vehicle’s fuel injectors at least once every three years is one of the best ways to prevent car starting issues.

A fuel injector that’s full of debris can affect the engine in many ways, such as by changing the trajectory of the fuel. This prevents it from getting injected into the engine, preventing the engine from starting.

Clogged fuel injectors also increase the pressure of the fuel and alter the air/fuel mixture, preventing it from igniting properly. Cleaning the fuel injectors not only keeps the air/fuel mixture balanced but also ensures the fuel is in optimum condition for combustion. It’s also strongly recommended to use fuel additives to flush the fuel system and fuel injectors to keep your engine in good condition.

Keep Your Car Battery Charged

As mentioned previously, a dead or dying car battery will make it take longer for your car to start — assuming it can start at all.

It’s a good idea to ensure your battery won’t run out of charge. This means investing in a car battery charger and some jumper cables or bringing your vehicle to a service center or auto shop regularly.

Replace Faulty Parts

If any of the parts related to starting your vehicle, such as the battery, the starter motor, or wires, are malfunctioning or damaged, don’t put off replacing them.

It’s a good practice to perform maintenance on your vehicle at least once a year to ensure everything is working as intended. If you’ve noticed that your vehicle starts slowly or struggles to start at all, it might be worth bringing it to a professional for diagnosis.

Reviewed By Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Tony Harlin is a Master Gas and Diesel Diagnostic Technician with over 18 years of experience. He works full-time at a large independent automotive shop as a driveability and repair technician working on all types of vehicles with a focus on diesels. ASE certifications include A1-A9, L1 and L2, as well as X1.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

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