back·fire
 /ˈbækˌfajɚ/  verb  , -fires, -fired, -fir·ing [  no obj  ]
  1 of an engine or vehicle : to make a loud sound when fuel is not burned properly
   The car backfired.
  2 : to have the opposite result of what was desired or expected
   Our plans backfired (on us).
  backfire  noun  ,  pl   -fires [  count  ]
   an engine backfire