If the starter is spinning the engine but nothing fires, you are missing one of three things: fuel, spark, or air at the right time. Battery and starter are fine - those would prevent cranking. Here are the five causes that account for nearly every "cranks but no start" case, ranked by how often each one is the answer.
Tell us your year/make/model and what you’re seeing. Our AI gives you the most likely cause for free in under 30 seconds.
Start Free Diagnosis →No login. No scanner needed.
A failed fuel pump is the most common single cause. Turn the key to "on" (not crank) - you should hear a faint hum for 2-3 seconds from the tank. Silence means the pump, relay, or fuse. Fuel pressure should be 35-60 PSI for most port-injection cars. Cost: $400 - $1,200. DIY: Hard. Severity: High.
Get a Free AI Diagnosis →A bad crankshaft position sensor is a top cause on Hondas, Toyotas, and GMs - the ECM cannot fire injectors or coils without it. Coil packs and ignition modules also fail with no warning. P0335 / P0340 codes point here. Cost: $150 - $700. DIY: Medium. Severity: High.
Get a Free AI Diagnosis →A worn key chip, dead key fob battery, or scrambled immobilizer module locks out fuel and spark. Watch the security light on the dash - if it stays on or flashes while cranking, the car thinks the key is wrong. Cost: $0 - $400. DIY: Easy. Severity: Medium.
Get a Free AI Diagnosis →Multiple failed start attempts can flood gasoline engines - hold the throttle to the floor while cranking to clear it. A timing chain that jumped a tooth (cranking compression is way down) is the worst-case version of this. Cost: $0 - $3,000. DIY: Easy / Hard. Severity: High.
Get a Free AI Diagnosis →Fuel gauges fail. Bad gas from a station with water in the tank can also stop a car cold. If the symptom appeared right after a fill-up, suspect the fuel itself first. Cost: $0 - $300. DIY: Easy. Severity: Medium.
Get a Free AI Diagnosis →If your scanner shows one of these codes along with the symptom, run a free AI diagnosis to confirm the root cause.
Describe what your car is doing and our AI gives you the most likely cause for your year/make/model - free.
Get Free DiagnosisNo login. No scanner needed. Takes about 30 seconds.
Quickest test: spray a small shot of starting fluid into the intake and crank. If it fires for a second and dies, you have spark and a fuel problem. If nothing happens at all, you have a spark or compression problem.
Fast crank means the battery and starter are fine - the engine is just not getting fuel, spark, or compression at the right time. Most often a fuel pump or crank position sensor.
Usually not. A weak battery cranks slowly or clicks. Cranks-but-no-start almost always means the cranking system is fine and a downstream system has failed.
Intermittent crank-no-start almost always means a heat-sensitive part: crank sensor, fuel pump, or coil. Test when it is hot and refusing to start - that is when the bad part is acting up.
It is the best clue. Scan the codes free at any parts store. P0335 / P0340 / P0230 / P0300-P0308 / P1450-range codes are all directly relevant.
$400-$700 for most cars, $700-$1,200 if the tank has to come down or the pump is integrated with the fuel module. Confirm with a fuel pressure test before authorizing the work.