You turn the key and the car won't start. Before replacing parts or calling a tow truck, pay attention to what the car does (or doesn't do) when you try to start the engine. The sound you hear tells you a lot about where the problem lies. In most cases you can narrow down the cause to one or two things without any tools.
Nothing Happens, Not Even a Click
You turn the key to start and there is complete silence. The dashboard doesn't light up, no warning lights come on, no sound from the engine bay. This is almost always an electrical problem at the very beginning of the chain.
The most common cause is a completely dead battery. If you left an interior light on, left the radio running overnight, or the battery has simply reached the end of its lifespan (usually 4-6 years depending on climate and driving habits), this is the result. Another possibility is the battery terminals. Oxidised or loose terminals break the connection and the car behaves as if there is no battery at all. If you see white or greenish powder on the terminals, that is oxidation. Clean them and tighten with a spanner.
Less commonly, the problem can be in the ignition switch (where turning the key sends the signal to start the engine). If the switch wears out, the signal simply doesn't get through. That is a repair for an auto electrician, but at least you know where to start looking.
You Hear a Click but the Engine Doesn't Turn
One audible click when you turn the key, then silence. The dashboard lights up, the warning lights work, but the engine doesn't crank. This narrows the problem to three places.
First, a weak battery. It has enough voltage for the dashboard and lights but not enough current to turn the starter motor (which draws enormous energy). If the lights flicker or dim when you turn the key, the battery is weak but not dead. Try starting using jump leads from another vehicle. If it starts, the battery is the issue.
Second, a faulty starter motor. If the battery definitely has charge (lights at full brightness, radio works) and you only hear a click, the starter isn't engaging. Old mechanic's trick: have someone turn the key while you gently tap the starter with a metal object. If the engine starts, the starter is on its way out. More about starter and alternator symptoms in the alternator and starter fault guide.
Third, a bad earth connection. The earth cable from the battery to the body or engine block can be corroded or loose. Without a good earth, the starter has no complete circuit and cannot engage.
Engine Cranks but Won't Fire
The starter turns the engine normally, you hear the familiar cranking sound, but the engine just won't catch. Here the problem isn't with startup itself, but with one of the three conditions for combustion: fuel, spark, or compression.
Fuel isn't reaching the engine. Turn the key to "on" (don't crank) and listen. You should hear a quiet hum from the fuel pump, usually behind the rear seats. If there is no sound, the pump may not be working. Before panicking, check you haven't simply run out of fuel, because the gauge isn't always accurate on older cars. If the pump is suspect, the fuel pump symptoms guide explains what to watch for.
No spark (petrol engines). Worn spark plugs or failed ignition coils mean fuel is getting through but cannot ignite in the cylinder. A typical sign: the engine cranks and you smell unburnt petrol from the exhaust. In damp and cold weather this is an especially common problem on cars that haven't been serviced in a long time.
Glow plugs not working (diesels). A diesel engine doesn't have spark plugs but glow plugs that heat the combustion chamber before starting. If the glow plugs fail, especially in cold weather, a diesel won't catch. The glow plug light on the dashboard should come on briefly when you turn the key to the "on" position and go off once the plugs are ready. If that light doesn't appear at all, the glow plugs or their relay are likely faulty.
Crankshaft position sensor (CKP). This sensor tells the ECU where the crankshaft is, without which it doesn't know when to inject fuel or fire the spark. Without a working CKP signal, the engine cranks but never fires. This typically happens without prior warning and diagnostics confirm it within minutes.
Starts Then Immediately Stalls
The car fires up, the engine runs for a second, and then it dies. Two culprits account for most of these cases.
Immobiliser doesn't recognise the key. Every modern car has a chip in the key that communicates with the immobiliser. If the chip weakens or loses sync, the engine can briefly start and then cut out because the ECU blocks operation. A typical sign is the key or padlock light flashing on the dashboard. This is explained in detail in the immobiliser guide.
Fuel supply problem. The pump can have an intermittent fault, enough to start the engine but not enough to keep it running. A clogged fuel filter can produce the same effect. If the car stalls when you gently apply throttle after starting, fuel is the most likely culprit.
Cold Weather, the Enemy of Starting
In winter, the number of cars that won't start in the Banja Luka area increases significantly, and for good reason.
A battery loses 30-50% of its capacity in low temperatures. One that starts the engine easily in summer can barely turn it over in winter. If your battery is more than 4-5 years old, the guide to recognising a dying battery will help you judge whether it will last through winter.
Diesel engines are particularly sensitive to cold. Beyond glow plugs that can fail, diesel fuel thickens at low temperatures and can clog the fuel filter. If your car struggles to start every morning once temperatures drop below zero, it is usually not one major fault but a combination of a weak battery and partially worn glow plugs.
When to Stop Trying and Call for Help
There is a point beyond which further attempts do more harm than good.
- If after three or four attempts the car won't start, stop turning the key. Each attempt further drains the battery and can damage the starter.
- If you smell petrol from the engine bay or exhaust, stop immediately. You have flooded the spark plugs and further attempts will only make things worse. Wait about fifteen minutes for the petrol to evaporate, then try once more.
- If the dashboard shows unusual warning lights (especially the oil or temperature light), do not force a start until you find out why.
- If you are in an exposed or dangerous location, do not try to push the car on your own. Call roadside assistance and wait somewhere safe.
Diagnosing a starting problem at the workshop is usually quick because a mechanic works through the same steps described here, only with instruments that immediately confirm or rule out each cause. If you are not sure what the problem is, come by the workshop and we will check on the spot.