I've got a 2001 ZD30. Just had a new fuel pump installed then I had to install a new head. It's going OK but under load towing a horse float it will go to 15 psi but quickly drop back to 8psi and little power.
I haven't got a Dawes valve or any of the other stuff, just the boost gauge and egt gauge.
Has anyone got any ideas of what could be loosing the boost?
Can the computer be doing that?
Cheers
Greg