Car Hard to Start?
Find Out What’s Wrong

The battery is the most common cause of hard starting — particularly in cold weather when battery capacity drops significantly. A battery that starts the car normally in summer may fail completely in winter. Symptoms include slow cranking, multiple accessories failing simultaneously and a clicking sound when the ignition key is turned. Car batteries typically last 3-5 years.

Diesel engines use glow plugs to preheat the combustion chamber — without adequate heat diesel will not ignite on a cold engine. Worn glow plugs cause hard cold starting — particularly in winter — often requiring multiple attempts before the engine fires. The symptom is usually worse on cold mornings and improves as temperatures rise. Glow plug replacement is straightforward on most diesel engines.

The fuel pump maintains pressure in the fuel system so fuel is immediately available when the engine cranks. A weak pump loses pressure when the engine is switched off — requiring extra cranking time to rebuild pressure before the engine fires. Hot starting problems (engine starts fine cold but is hard to start when warm) are a classic sign of a failing fuel pump.

The crankshaft position sensor tells the ECU the exact position of the crankshaft — essential for timing fuel injection and ignition. A failing sensor causes intermittent starting problems that can worsen suddenly. The engine may start normally most of the time but occasionally refuse to start at all. An engine management light may or may not be present.

On petrol engines worn spark plugs require more voltage to fire — and on a cold engine when compression is lower this can be insufficient. Hard cold starting that improves once the engine warms up is a classic worn plug symptom on petrol cars. Replacing the full set of plugs is inexpensive and should be done at the manufacturer specified interval.