I have a auto dpfi harness I would like to convert to a manual mpfi harness cause I wanna jump to obd1 but I'm having issues jumping with harness you can buy any imput would be useful it's a b18a1 1990 Honda Civic wagon

 

read my build thread Marcos new work car 90 sedan
your answer is in there with pictures

 

Yes, you can. I'm in the process of making my own MPFI harness for my Sedan right now, using an auto DPFI harness. I'm taking my time because I want all the wires to be inside the loom and look clean. You will need some extra wire, and it has been helpful to have a second auto DPFI harness beside me to harvest the occasional pin and connector out of. When I pulled the intake manifold (94 Civic EX) from the junk yard, I also cut and took the portion of the harness with the injector wiring on it. I was considering doing a writeup once done.

 

yes, as long as you rewire to manual specs and remember to add the wiring for reverse lights because auto needs a ground for the back up switch (auto has it in the shifter), remove the egr valve wiring (if its present). your essentially gutting it and building a new one.

 

Also...to do it right, you should use shielded wire for the CYP. I've seen lots of people don't, but to do it right, you should.