P0316Powertrain
Powertrain · SAE
Misfire detected at start-up (first 1000 revolutions)
Meaning
The ECU detected misfire events in one or more cylinders during the first 1000 crankshaft revolutions following engine start. During this window the engine is still cold and the closed-loop fuel control system is not yet active.
Common causes
- Cold, fuel-fouled or worn spark plugs
- Injectors leaking at rest flooding the cylinders during engine-off periods
- Low fuel pressure at first start (weak pump or faulty check valve)
- Ignition coils with reduced efficiency when cold
- Excessively rich mixture during the initial start-up phases
Symptoms
- Difficult or prolonged cranking
- Rough idle during the first seconds after start-up
- White or grey exhaust smoke at start-up
- Check Engine light that illuminates only on cold starts and disappears after warm-up
- Shuddering or jerking immediately after start-up
Severity
Moderata: Cold-start misfire can damage the catalytic converter and indicates ignition or fuel system components that need inspection.
What to do
- Inspect spark plugs for signs of flooding or wear
- Test injector seal integrity with the engine off (injector leak-down test)
- Measure residual fuel pressure after engine shut-off
- Verify ignition coil efficiency at low start-up temperatures
- Check cold-start enrichment parameters in the ECU with a scan tool