deadadjective
The engine started and turned over for few seconds before everything went dead again.
For a minute, I couldn't hear anything, and I thought the phone line had gone dead.
The air conditioning in the library went dead on the hottest day of the year.

SMART Vocabulary: related words and phrases

Machines - not functioning
act up
balky
blooey
break down
broken
brokenness
brownout
downtime
fail
flat
malfunction
outage
seize
seize up
short circuit
shot
shudder
shut
shut (something) down
whack