Symptom
The starter turns the engine normally but it never runs. Points at fuel, spark or crank position signal rather than at battery or starter — a genuinely useful distinction to report.
Also described as: turns over but won't start, cranks no start, spins but doesn't start, turns over but doesn't fire, استارت میخورد ولی روشن نمیشود, موتور میچرخد اما روشن نمیشود, gira y no arranca, marcha pero no enciende, da vueltas y no enciende, تدور ولا تشتغل, المارش يلف بدون تشغيل, تلف وما تولع
12 of the 31 codes that produce this symptom indicate a fault where continuing to drive risks damage or is unsafe. If the symptom is sudden or severe, treat it as one of those until a scan says otherwise.
The starter doing its job is a real finding rather than a non-event: it clears the battery, the cables, the solenoid and every permission switch in one observation. What is left is fuel, ignition and the crank position signal, and they are separable in a few minutes without dismantling anything.
Take the crank signal first, against instinct. The engine control unit uses it to decide when to fire an injector and when to fire a coil, so its absence removes fuel and spark at once and mimics either. It is checkable without tools beyond a scan tool: watch live engine speed while somebody cranks. A visibly turning engine reporting zero rpm is the sensor, its wiring or its reluctor. Japanese diagnostic guidance puts this check early for exactly that reason, and the failure is characteristically heat-dependent — fine cold, absent after a run.
Then fuel, by ear before by gauge. With the door open and the ignition switched on, a working pump primes audibly for a second or two. No prime narrows it to the pump, its relay, its fuse or its supply — and the relay is the cheap end of that list, so prove the supply before condemning the pump. If it primes but the engine still will not fire, gauge the rail against the manufacturer's figure rather than trusting the sound.
And treat an unusually fast, smooth, hollow-sounding crank as a stop signal, not a clue to note. That is compression lost across every cylinder, which on a belt engine means the belt has jumped or broken; continuing to crank an interference engine is what converts a belt job into a cylinder head.
| What you find | Likely cause | How to confirm it | What fixes it |
|---|---|---|---|
| Scan tool shows no engine speed while the engine is plainly turning | Crankshaft position signal missing — sensor, wiring or a damaged reluctor ring | Read live rpm during cranking. Then check the sensor's resistance or signal at the connector, and inspect the reluctor for damage or debris before fitting a sensor. | Renew the sensor or repair the wiring. If the reluctor is damaged, a new sensor changes nothing. |
| No pump prime audible when the ignition is switched on | Fuel pump, its relay, fuse or supply — not necessarily the pump itself | Back-probe for supply at the pump connector during the prime window. Supply present and no pump means the pump; supply absent means relay, fuse or wiring. | Renew whichever stage the supply test names. A relay is a fraction of the cost of a pump and fails far more often. |
| Pump primes, but the rail will not reach its working pressure | Weak pump, blocked filter, restricted line, or a regulator dumping to return | Gauge the rail with the ignition on and during cranking against the manufacturer's figure. Clamping the return separates a dumping regulator from a weak pump. | Filter first where it is due, then pump or regulator on the gauge reading rather than on age. |
| No spark at any cylinder, on a petrol engine | Ignition supply, the coil driver, or the crank signal upstream of both | Test for spark at a plug with an in-line tester. Absent on every cylinder points upstream to supply or crank signal rather than to coils, which rarely fail as a set. | Repair the supply or signal found. Replace coils only where the failure is genuinely per-cylinder. |
| Fires briefly on aerosol starting fluid and stops | Ignition and compression are present; fuel is not arriving | This is a strong result rather than a trick — it isolates the fault to the fuel side and makes a pressure test the next step rather than a guess. | Pursue the fuel side alone. Do not fit ignition parts after this result. |
| Cranks fast and smooth with a hollow note | Compression lost across the engine — timing belt or chain jumped or broken | Stop cranking. Confirm camshaft rotation with the engine turning, or take a compression reading on two cylinders. | Recover rather than drive. Belt or chain, with valve inspection before reassembly on an interference engine. |
| Diesel that cranks well and never fires, warm or cold | Loss of rail pressure or fuel supply — air in the system, a failed high-pressure pump, or a leak-off fault | Read live rail pressure during cranking against the minimum the system needs to inject. Measure injector leak-off across the set; one bad injector can hold the whole rail down. | Repair the leak, injector or pump on the measurement. Prime the system properly afterwards. |
Scan tool shows no engine speed while the engine is plainly turning
No pump prime audible when the ignition is switched on
Pump primes, but the rail will not reach its working pressure
No spark at any cylinder, on a petrol engine
Fires briefly on aerosol starting fluid and stops
Cranks fast and smooth with a hollow note
Diesel that cranks well and never fires, warm or cold
Listed with the codes that most typically present this way first — the likeliest place to start.
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
An engine that cranks strongly but never fires is missing one of three things: spark, fuel, or compression. The fastest route to a diagnosis is not finding the fault — it is findin...
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