Auto Repair Help
KYLE’S CORNER – AUTO REPAIR HELP

DIAGNOSE ENGINE CRANKS SLOWER THAN NORMAL

by Kyle McFadden


SYMPTOM SUMMARY
The engine cranks over slower than normal. The engine may fail to start as a result of the slow crank speed.

USUAL CAUSE
Low battery charge can result in slow cranking. This can be caused by a defect in the charging system or something as simple as leaving the lights on. A defective starter can also be the cause.

DIAGNOSIS
Start your diagnosis with determining whether the battery is in a proper state of charge. If the vehicle is able to be jump started and cranks over normally, the batteries state of charge could be low. If the “battery” or “charge” light comes on after the vehicle is started, a failure in the charging system is likely. You should refer to the “Battery or Charge Light On” symptom article on this website. If the battery and the charging system are functional and the symptom is more pronounced when the engine is hot, the most likely cause is a defective starter.

PRECAUTIONS, TIPS, and NOTES
Most part stores or repair facilities can charge and test your battery for a nominal charge. Battery cell testers are available at most parts stores andt can test each cell of the battery. This will only work on batteries that have removable cell covers. Use caution when working around batteries. Batteries contain acid that is very corrosive and can burn your skin. Always wear safety glasses and use caution when working around hot or rotating engine parts.

(Kyle has an affinity for Pale Ale and tooling on his 1956 Chevrolet Nomad Station Wagon.)

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1 Comment on "Diagnose Engine Cranks Slower Than Normal"

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9 months 13 days ago

I have a Hyundai that is slow cranking. The problem just appeared today, and I thought maybe a door hadn’t been shut good and the dome light on or something. I never found the source of the issue. After hrs of disuse, battery rests at 12.6v, so not low. While running, the alternator is clearly charging the battery as the voltage gets up to 15v, and runs very smooth. Typically in my experience a starter doesn’t so much present itself with a slow crank , but with clicking, and a more uneven cranking.

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