An engine that cranks unusually fast (almost spinning free like there is no resistance) and refuses to start is a classic sign of lost compression. The crank speed is high because the cylinders are not building pressure to slow the piston down. This usually means a snapped or skipped timing belt or chain, but it can also be a hydrolocked engine that has been cleared, broken valve springs, or massive vacuum leak. This is serious - stop cranking.
Fast spinning with no start usually means the timing belt or chain has broken. On interference engines, more cranking can drive valves into pistons. Tow it - do not keep trying.
Each cause is rated by likelihood, repair cost range, DIY difficulty, and severity. Start with the highest-probability cause and work down.
The #1 reason for fast cranking with no start. Without a belt or chain, the cam does not turn - no valve action, no compression. On interference engines (most modern cars) this also bends valves. Tow to a shop.
The belt or chain is still intact but has skipped one or more teeth. Compression is reduced or zero, cam timing is wrong. May throw a P0016 or P0017 code along with no-start.
If the timing belt broke before, the valves may already be bent. No compression on any cylinder. Compression test will show 0-30 PSI across the board.
A snapped valve spring keeps that cylinder's valve open. The piston cannot compress against an open valve - no compression on that hole. Listen for a fluttering exhaust if it does fire.
A completely disconnected intake hose or blown intake manifold gasket can let so much air in that the cylinder loses compression. Less common but easy to inspect.
If water was sucked into the engine, bent rods or cracked pistons can result in zero compression. Always check the air intake for evidence of water entry.
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If your scan tool is showing one of these codes alongside this symptom, that is your starting point. Click any code for the full diagnosis.
Because the cylinders are not building compression. Without compression there is no resistance to slow the piston, so the starter spins the crank much faster than normal. The most common cause is a broken or skipped timing belt or chain.
Possibly. If you have an interference engine (most modern engines), a broken timing belt or chain often bends valves. A compression test confirms whether damage occurred. Stop cranking immediately to avoid making it worse.
On interference engines, valves and pistons share space at certain points in the cycle - if timing fails, they collide. Non-interference engines leave enough clearance that nothing hits. Most engines since 2000 are interference. Look up your specific year/make/model.
No. Do not crank, do not tow with the rear wheels down on a RWD or 4WD, and have it flatbed-towed. Continued cranking on an interference engine causes more valve damage.
It measures the pressure each cylinder builds. Normal is 130-180 PSI. With a broken timing belt or chain, you will read 0-30 PSI across all cylinders. A $40 compression tester and 15 minutes will tell you exactly where you stand.
Timing belt or chain replacement: $800-2000. If valves bent, add $1000-2500 for head work. Worst case (rebuild or replace engine): $4000-8000. Get a quote based on a compression test first.