| The second stroke of the four stroke engine cycle, in which the piston moves from the bottom dead center in the intake valve is closed, trapping and compressing the air/fuel mixture in the cylinder. | |
| Data link connector | |
| The burning of the air/fuel mixture. | |
| A magnetic, hall effect, optical or magneto resistive sensor usually mounted internally in the engine, externally to the engine are in the distributor to inform the ECM or PCM of the crankshaft position location of No. 1 piston, and crankshaft speed for ignition timing and other calculationneeded by the system where RPM is in input. |