Why your Car’s Cranking may be Slow yet Battery is good (+ What to Check)

Is your car taking longer to start when you turn the ignition key to start yet the battery appears to be in good condition?

Wondering if this is something you may be able to fix yourself?

The car’s lights may come on without dimming and yet the car engine has a sluggish start.

The good news is that in some cases you may be able to fix the problem of slow cranking and quite easily without having to engage the services of a mechanic.

In this post, we’ll look at the common reasons why the car engine may crank slowly even with a charged battery and how you may be able to fix the fault

Why Car is Slow to Start but the Battery is Fine

Note: This assumes that the car battery has been properly tested – with a load test done. If not done, this should be the first check you do.

If the car engine takes unusually long to turn the engine over then it might be because of:

#1. Check the cable connections to the battery for any corrosion or looseness. Confirm that there is no corrosion on the battery terminals.

Corrosion around the terminals limits how much current flows to and from the battery.

This can slow down the cranking as there is not enough current to turn the engine over.

Tips to remove corrosion on battery terminals

To clean corrosion off battery terminals, mix baking soda with warm water or any other good quality battery cleaning solution then pour over the battery terminals.

Using a wire brush, old toothbrush, or scouring pad scrape off the powdery residue until the battery terminals are free of the powdery substance.

Make sure to clean the powdery residue off the connecting wires by pouring baking soda mixture over the terminals and brushing it off.

Also, confirm that the battery cable connections are firm. Loose battery cable connections also can cause slow cranking or stop the car from starting.

To check their that they are firmly connected, give the battery clamp connections a gentle wiggle. They should stay locked onto the battery posts if firmly connected.

#2. The car may have loose cable connections to the starter or a faulty starter. Loose starter cable connections cause voltage drops in the car starter circuit that can also result in slow cranking.

You can check for voltage drops by running a starting voltage test, check with a qualified mechanic.

A faulty starter likely with older cars that have done over hundreds of thousands of miles can also cause slow cranking.

Consult a qualified mechanic if the car is unable to start or you suspect that it has a faulty starter.

You may also be interested in Why the car starter may be drawing large currents

#3. Spark plugs may require cleaning or replacement. When was the last time the spark plugs were replaced? If the spark plugs are faulty then the car will have trouble starting and will not run smoothly even in idle after starting.

#4. Mass airflow sensor (MAF) requires cleaning or is faulty. A faulty or dirty MAF can cause sluggish starts in the car. You’re more likely to have MAF sensor problems in cars that have been in service for several years.

The MAF sensor helps make the right adjustments so that the correct amount of fuel can be mixed with the available air for proper combustion for the engine to start.

#5. (For diesel cars only) – cold weather or glow plugs are faulty. Diesel cars rely on glow plugs to heat up the air sufficiently so that it ignites immediately when mixed with fuel when the car is starting.

If the glow plugs are faulty or it is extremely cold, the air may have to be heated up at least several times by turning on the ignition and switching it off when the heater light goes off before engaging the starter.

You may also be interested in Why the car may be turning over too fast

The Danger of Sluggish Starts?

Sluggish starts can drain the battery flat as the car starter draws large currents from the battery with each attempted start. Car starters are known to draw between 60 – 200 amps with each start.

Over several starts, depending on the battery condition, the battery may be short on charge and not able to turn over the engine.

Final Thoughts

A car engine that is cranking slowly yet the battery is charged and in good condition may have loose or corroded battery terminals, a faulty starter, mass airflow sensor, or faulty glow plugs.

If you have the skills, work through the possible causes of failure otherwise consult a qualified mechanic for assistance.

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