Maybe someone would want to split this thread up since its kind of taking a new direction....
I finally got to do a little tinkering tonight. I was pleasantly surprised at the similarities the pumps share and compatability.
What I have:
stock steel gas tank and pump from TBI equipped 90yj
stock 15/20 gal plastic tank and pump from MPI equipped 94YJ
Both pumps side by side
TBI pump wiring
MPI wiring
Both have 3 wires inside, 1 for the sender, 1 for the pump, 1 ground. Each had the same in similar enough positions that wiring was a no brainer. I had to mix and match wires because of length only.
There are 2 brackets for holding the pumps in place. The bottom one is fixed and determines depth in tank. The top bracket bolts into a slotted hole along the assembly itself.
Removed the rubber grommet from the TBI housing and installed in onto the MPI housing. Fit perfectly
after test fitting it TBI pump into the MPI housing it seemed to bend the top bracket and while it would have held fine I wanted it to fit better. So I entended the slotted hole about 1/4"
just drilled and filed, nothing fancy
mounted up the pump, fit like it was meant to be there
then wired it up and plumbed it. I actually reused the hose that was originally attatched to the TBI pump. It was slightly longer than the MPI hose, and the holes had a slight offset to them so it helped make up that distance just about perfectly.
The strainer from the TBI pump will have to be re-used as they were a little different
I checked the wires coming from the top exterior of the housing, 3 wires. 1 for the level sender, 1 for the pump and a case ground.
It will probably be a few days before I put the tank completely back together and see if it actually works!
Other things I am gonna need (and already have) are new fill/vent hoses as they are shorter and wider than the originals. New gasket for the rectangular pump cover.