Car Cranks But Won\'t Start: 5 Suspects | Ladson Auto

The engine spins over strong — rur-rur-rur-rur — sounds completely normal, and just... never catches. Here's the good news hiding in that sound: your battery and starter are FINE. The engine is turning; it's just missing one of the three things it needs to run.

The short answer: An engine needs fuel, spark, and compression delivered at the right time — cranking-without-starting means one is missing. The five usual suspects, roughly cheapest first: the anti-theft immobilizer silently cutting fuel ($0–150 — check for a flashing security light), fuel delivery — empty-in-disguise, a dead fuel pump or clogged filter ($0–900), spark/ignition faults ($150–500), a failed crankshaft or camshaft position sensor ($150–400) — the modern classic, especially when a hot engine won't restart — and timing or compression problems (diagnosis first; this is the big-conversation one). The pattern of when it won't start does half the diagnosis.

Cranking in the driveway right now? Call 843-494-9179 — a few questions over the phone often narrows it. Or Book Online.

---

📋 In This Article

---

What "Cranks Fine" Rules Out

A strong, even crank clears three suspects instantly: the battery (it's spinning the engine), the starter (it's doing its one job), and the connections feeding them. If instead you're getting clicks or silence, you're in a different article — click-click points here , total silence points here .

One useful refinement: a crank that's unusually fast and free — the engine spinning with less resistance than normal — is itself a clue, and not a cheap one (see Suspect 5).

---

The 5 Suspects

Suspect 1: The immobilizer — $0–150

The anti-theft system doesn't recognize the key, allows cranking, and silently blocks fuel or spark. Check the dash for a flashing key/padlock light while cranking, and try your spare key. Weak fob batteries and aging key chips cause this constantly, and it's the cheapest suspect on the list — which is why it goes first.

Suspect 2: Fuel delivery — $0–900

The engine is starving. In escalating order: an empty tank lying behind a faulty gauge ($0 + two gallons answers it), a clogged fuel filter ($80–200), a dead fuel pump relay ($20–100), or the fuel pump itself ($500–900). The classic pump test: have someone turn the key to ON (not start) while you listen at the fuel door — a healthy pump gives a 2-second hum. Silence is suspicious. Pumps also love to fail on hot days with a low tank — the fuel in the tank is what cools the pump.

Suspect 3: Spark — $150–500

Nothing to light the fuel: failed ignition components, or on some cars a single sensor feeding all of them. Often announced in advance by misfires and stumbles in the weeks before — a car that ran rough Friday and won't start Monday is telling a spark-or-sensor story.

Suspect 4: Crank/cam position sensor — $150–400

The modern epidemic. These sensors tell the computer where the engine is in its rotation; with no signal, the computer fires nothing — perfect crank, zero response. The signature pattern: runs fine, then won't restart when hot, then starts again after cooling 20–30 minutes. Heat-soaked sensors fail exactly this way, and Lowcountry summers audition every aging sensor. Usually sets a code the scan reads in seconds.

Suspect 5: Timing or compression — diagnosis first

The serious end: a snapped timing belt (on engines that have one), a jumped chain, or lost compression. The tell is often that unusually fast, free-spinning crank — the engine turning without the resistance compression provides. On "interference" engines a snapped belt can damage valves, which is why this suspect gets a compression check and honest talk before any money moves — sometimes it's a repair, sometimes it's the repair-or-replace conversation .

---

The Patterns That Point the Finger

Tell us which of these matches and the suspect list shrinks before the hood opens:

• Won't restart hot, starts after cooling: crank/cam sensor (4), sometimes fuel pump (2).
• Hard starting mornings for weeks, now nothing: fuel pressure bleeding down — pump or regulator (2).
• Ran rough recently, now won't start: spark side (3).
• Died while driving, cranks but won't restart: pump, sensor, or timing (2/4/5) — the died-while-driving guide covers that scenario .
• Cranks faster than normal: timing/compression (5).
• Only after rain or a car wash: moisture in ignition components or connectors (3) — a very Ladson pattern.
• Right after getting gas: a slim but real chance of contaminated fuel, or an EVAP purge issue flooding the engine.

---

Price Table

Suspect	Typical tell	Cost in Ladson area
Immobilizer/key	Flashing security light	$0–150
Empty tank / bad gauge	Gauge says fine, engine says no	$0 + fuel
Fuel pump relay	No pump hum at key-ON	$20–100
Fuel filter	Long-crank history	$80–200
Ignition components	Recent rough running	$150–500
Crank/cam sensor	Hot no-restart pattern	$150–400
Fuel pump	No hum, hot-day failures	$500–900
Timing belt/chain	Fast free crank	Diagnosis first

---

What NOT to Do While It's Cranking

• Don't crank endlessly. 10 seconds max per attempt, a minute of rest between. Marathon cranking overheats the starter (a part you've currently ruled out — keep it that way), drains the battery, and on a flooding engine washes oil off the cylinders.
• Don't spray starting fluid into a modern engine as a habit. As a one-time test it has diagnostic value (fires briefly = fuel problem; nothing = spark/timing), but repeated use is hard on engines — and it answers a question a scan tool answers better.
• Don't replace the fuel pump because a video said so. The hot-restart pattern that gets pumps replaced is more often a $200 sensor. The scan and a fuel-pressure gauge settle it for the price of a real diagnostic — cheap insurance against a $700 guess.
• Don't keep trying if the crank suddenly sounds fast and free. On a possible snapped timing belt, every extra crank on an interference engine risks valve damage. Stop and call.

---

---

Tell Us the Pattern — We'll Find the Suspect

Call with the story — when it happens, hot or cold, what came before — and we'll often name the likely suspect on the phone. In the shop, it's codes, fuel pressure, and spark checks in order, then a written estimate before any part goes on. Repairs carry our 12,000-mile warranty, and repair customers get 15% off same-day loaner cars.

📞 Call 843-494-9179

Or book online: Book Appointment Online

---

---

Written by the mechanics at Ladson Auto Repair Shop, 3322 Ladson Rd, Ladson, SC 29456. Serving Ladson, Summerville, Goose Creek, North Charleston, and the greater Charleston, SC metro area.