I bought this 1991 F150 last year and have tinkered with it a little. It is not a daily driver. Has 38.5" Super Swampers, 5 speed, 4x4, 5.0 V8 with a few minor mods. Use mostly for trail & mud fun.
When I got it, it had no cat converters, just true dual exhaust with Flowmaster 40s.
I have started to see some black smoke out the exhaust I did not see before, and i think it might be because an O2 sensors on the exhaust does not have a good seal and it leaking exhaust around it.
My question is, Can I remove all of the other emmission garbage that is on still like the A.I.R. pump, vapor cannister, vacuum reservoir, and AIR pipes? Are any of these parts essential to the smooth running of the engine even without cats?
I plan on getting a jet chip for it alsoin the near future. Does not seem to run bad.

 

You can check the computer for codes to see why it's smoking. This thread explains how: https://www.f150forum.com/f10/how-retrieve-trouble-codes-obdi-10907/
You can remove the smog pump stuff but you need to leave the control solenoids hooked up or the check engine light will come on. Leave the EGR, the truck will run better with it. Leave the vapor canister or the truck will stink like gas, and leave the vacuum canister.

 

Thanks Sean.
What about the AIR pipes at the rear of the engine, and I guess the O2 sensors need to stay correct?

 

Yes, the smog pump and AIR tubes can be removed, but you need to leave the control solenoids hooked up to keep the engine light off. The oxygen sensors need to stay so the truck runs right.

 

You should leave the charcoal or vapor canister and the vacuum can in place These do not make any difference in running and removal of the charcoal can may let moisture into the fuel tanks. The charcoal can manly purged on startup and sealed during running periods, though at low vacuum condition it might purge then.