The lo-side cap (black) can be in different places depending on OEM specs.
For example, on my '91 2wd jdm it's behind and on the left side of the left front wheel near the fan shroud.
On my '91 4wd jdm it's behind the driver's seat (righthand side seat) under the smaller of two removable covers secured by a wingnut. In this van I have had to hang the manifold inside the car, running the hoses through the engine bay and maintenance window.
Good luck
BTW, this thread has really helped to expand my understandingThank you!