Stormbringer issue 4

Thunderwing returns to Cybertron. The Predacons prepare to nuke Cybertron in order to destroy Thunderwing. The wreckers fight alongside the predacons until the nuke is ready. Jetfire learns that the more Ultra Energon Thunderwing uses the quicker is runs out. Optimus begins blasting Thunderwing until he runs out of energon and dies. Optimus then begins heading for earth after learning that there is more ultra energon on earth, which is interesting because he had just received a call from Prowl on earth asking for help.

From Teletraan I: The Transformers Wiki, a Wikia wiki.