Hello,
I am trying to figure out what this thing is in the first picture. Some sort of egr valve for emissions I am guessing. The black steel tubes shown in the pic lead to back of engine, and to the front where they connect to the air pump? in the pulley system. I am taking it that the black tube in the back leads to the exhaust, and possibly effects the reading of the O2 sensor? Hard to see back there..
First pic is of a random 1990 ford f 350 7.5 dually I found on the net for reference. I bought my truck with this all ready removed. My engine is in the second picture without the unit.
Do I need this unit, or can I just run a hose in place connecting both pipes together? I am getting some check engine codes but the truck runs great. This truck is not required to have emissions testing where I live but I want it to run as best, and efficient as possible. If I don't need this its staying off.. Also.. They had a PCV valve with one inlet, adn when I went to buy a new one it had 2 inlets. One standard hose size and another that looks like it has a vacuum line with an optional little cap that came with it.. Thanks in advance..

 

All items shown are parts of the air injection system which is designed to help fire off the cats when the engine is cold. The 02 sensors can set codes if not functional, but do not generally cause issues when warm.

The open part in the top of the second image is actually a muffler & is actually the way it looks.

The pipe along the valve cover, I can't say.

The nipple cap on the PVC is normal.

There are dozens of variations from year to year & between models so visual comparisons from one to another are often misleading.

Other folk can possibly expound on your particular year & setup.

Hope this helps.

 

Thanks for clarifying things a bit for me.. I'm going to go grab length of hose and hook it up and see what happens. Should hold me over till I get to the junk yard and find the right part.. I'd still like to know if this will make the truck run rich or lean or effect the fuel economy other then emissions. If not I may just remove the pump and buy a shorter belt.