Backfire: An engine is said to backfire when fresh unburnt charge of fuel burns in the exhaust system on account of leakage from the exhaust valve. Related posts: Personnel Management Operative Functions Administrative Role of PM Competency HR Management Role Change Personnel Policies Personnel Procedures Appealed Policies Implied Policies Specific Policies Personnel records Research Pure research Personnel research Attitude or Opinion Survey Turnover Secondary research Applied research Personnel audit Read more articles Previous PostBrake Mean Effective Pressure (BMEP) Next PostBack pressure