why am I getting black smoke out of tail pipe?

I took a tank off from a 1995 ford f-250 and put it on my 1992 f-250 I had to wire it up seeing as they have different plugs on them and was wondering if maybe this could be the issue. Truck ran fine till the pump stopped working ( which is why the tank change) now it runs but doesn't want to accelerate unless vacume is off map sensor. So I am wondering if maybe these pumps have different outputs. I am working with very little cash flow is why I tried tank from a 1995. when I take vacume off map sensor is when I get the black smoke.

Humm... I'll have to think on it awhile... Don't think pump pressure is different... I be back!... Have you changed the fuel filter? Replacement tank good and clean/dry.. No water??

Yes new filter and tank was clean with no water

Going to have to test the fuel pressure... Google it..may can get/rent a gauge from parts store..

I am going to try to get a tester in the morning and will let you know what pressure is after. And thanks for your help.

Cool... In fact, it might not be enough!

Okay sorry for the late response but I have some different info on my issue. I pulled the return gas line and plugged it off and I get pressure and truck runs great but I am worried that I have to have return so I am wondering what could cause this issue. A little other info (don't know if important or not) the truck had dual tanks but the back one had been taken out before I got it and it ran great until after the pump went out.

Replace the fuel pressure regulator!!!!

Truck is back running but falls flat when trying to accelerate unless I block the vacuum from the map sensor and then it still isn't right and with vacuum off truck wont shift.