Second stage engine activates on lift-off (no, it's not the staging)

[KerbMav]

Remove both engines in VAB and delete them from your cursor.

Pick up "new" ones from the part list and put your rocket back together.

Just a blind shot though.

[dandrestor]

Remove both engines in VAB and delete them from your cursor.

Pick up "new" ones from the part list and put your rocket back together.

Just a blind shot though.

Well, I just noticed the same phenomenon on another rocket I just build, so I guess it's about the same thing as what you were suggesting. My money now's on a problem with one of the mods I'm using. I will try removing them one at a time and see if that helps.

[Callmedave]

Im running stock and had a similar problem with the chutes from stage 5 opening when i launched (rockets from stage 9)

I placed an empty stage in front of 5 and this cured the problem, you could do this on the launch pad.

Another option is to set 'toggle engines' to an action group, toggle them off before launch, and toggle them back on when required.

Hope that helps.

[Shna_na]

Try it completely without any mechjeb parts. It might be an older version of the mod being problematic with the new parts (such as Kerbal Engineer - with the new parts, it just decides that they're too confusing and eliminate that stage from calculations. At least in my experience). Are you using an up-to-date version of the mod? Is this version 0.23.5-compatible? Check this for all mods used. I know it's a pain but such is mod installation, eh?

[dandrestor]

I reverted to stock and the problem is gone. It was probably one of the mods. Now all I have to see is which one

[MisterFister]

I'd be interested to see this .craft file, if you don't mind. I run a similar modset and I've had ghost-staging issues in the past. This may help me tackle other problems, as well.