Hey guys, im switching out my carb from an old holley 4130 econo something other that came on my 85 firebird. (upgrading to a street demon 625) I could do the regular swap carbs and be good, but thats not me. I took the carb off, saw that super dirty not taken care of intake manifold and knew i had to take that off to clean it. the guy before me that i bought the car from didnt take care of the car so well as he said, black coolant, jerry rigged wiring, oil gunk under the valve covers to just name a few things... the carb had some vacuum lined choke that had vacuum lines going every which way. anyway, im trying to clean up the inside of the engine bay and taking out anything unnecessary. I live in arizona and where im at they dont do emissions or anything... as long as it has headlights, mirrors and blinkers its good lol. in the picture i posted with this there is a big unit on the left side of he picture right behind the alternator, a little to the left. what the heck is that. it has a bunch of tubes going every which way and makes the inside of my engine bay a complete mess. now im not a super big motor head, i cant tell you what cam i have or the gear ratios or anything like that... but i probably do know a little more than the average joe. i feel stupid for asking, but is that thing needed? the charcoal canister is already out as well...also, is that an egr valve next to the carb? is that thing needed? i heard some people take the egr valve out and put a bypass... anywho, let me know what you guys think... if i need a better picture let me know lol.

 

Smog pump diverter valve. Switches the air from the smog pump from going to the exh manifolds (when the engine is in open loop) to the catalytic converter (when the engine is in closed loop). You can remove that valve, the smog pump and ALL of the related smog pump lines to clean up the engine bay. ECM doesn't even know if it's operating. However, DON'T rely on the check valves at the ends of manifold air injection line logs alone to keep exhaust from back-feeding into the engine bay. You need something to positively seal them up.

 

wow, never would have guessed that! awesome, now i can look it up. the guy before me said he put in a straight pipe or a cat-back exhaust system. that thing sure gets in the way though. made my fuel pump install take a looooot longer than it should because i couldnt reach in to get the bolts (even from the bottom) Thank you very much for the info though. i think im going to take it out though, more time to research stuff!what about the egr? any input about that?

 

Yes the saucer shaped part next to your carbon base is the egr valve. No you do not need it for your car to run. Since you are switching carbs already I would suggest installing a new intake as well. They come without the egr boss so you would be all set.