im wondering, when to turn key on to prime fuel system, do all four injectors open or just primaries?
im using a e6k if it matters

 

If im not mistaken its just the primaries when in rotary mode. I think.

As personal choice i usually either dont use the primer map and just go off the post start enrichment maps, or lower the primer as much as possible. Sometimes they can contribute to engine flooding when you have turn the key on and off several times. Especially if they are set too high.

If you dont want to use the primer map, just zero it out.