No, you pull that and the cat will overheat and change colors on the outside,not get cooler, seen it happen many times.

 

why dont yall just take'em off

 

I would love to, but then I would not be legal. We have smog checks where I am from and they visually check for them with a mirrior and if they are gone you will not pass and can not register your rig.

 

For the one that mentioned that the smog pump has nothing to do with the intake, it does. On the 79 351M the smog pump feeds into a port on the front of the intake manifold. You do have to plug that or you get some nasty noise under the hood. Later years may not be the same, but for the smog equipped 351M, that's where it goes.

 

and since we werent talking about a 351m it wasnt mentioned :-)

 

where did you get a 351m with smog equipment?I've got a 78 which originally had a 351m in it...now it's got a 400....never even came factory with the smog stuff......ahhh you musta got a lemon ha ha ha.....and no...the PO didn't take it off...I'm the second owner....

JR

 

There has not yet been a mention of what engine this is, or what year the vehicle is. Since it's in the Big Bronco section, it could be for anything. It was just to point out that the thought wasn't completely wrong, and that he could have possibly been thinking of another engine.

And where did I get it, I'm the third owner of a almost completely stock 79 Bronco Custom. Everything was intact when I got the truck, and the only thing removed by me is the smog system. It is a work in progress. Oh yeah, low mileage too, 126,000 original miles. Confirmed by first, and second owner. The '78 models were a mix when it came to the smog equipment. In 79, we didn't have a choice.

My apologies for making it sound like I was talking about the current engine, I was simply making the association.

 

just givin ya crap, since your new remember that we really dont get personal on here but will raze each other from time to time.

 

Oh yeah, I'm always up for that. I'm used to some other forums where that isn't the case, so I'm used to having guns ready.

 

Ha ha...I'm a pretty big boy so you better have a pretty big gun.....ain't no fun on here if ya cain't razz each other.....I knew you where just associating....but I ain't never seen that old a truck with smog stuff...kinda curious actually......

JR

 

All a smog pump does is pump fresh air into the exhaust system so it dilutes
the gases to pass emissions. Our lovely EPA gave standards to pass and our Automotive industry couldn't meet, thus came the Smog pump. The pump robs a few horses just for that fact. Any time you add a pulley it robs a few horses to get the job done. note: this why in racing they have a switch that turns off the ALT when racing, under yellow flag they flip the switch to charge the battery, Every pony counts.
Depending on the state you live in if the smog pump is removed it wont pass your state inspection. How ever, I removed the smog pump from my 79 F-100 and it didn't over heat the cat. And my 96 Bronco AND my 90 Bronco II doesn't have a pump on it and they have cats on them. So you could find a 96 5.8 that has a pulley that takes the place of the smog pump, and you wont have a belt issue. Or go to summit they have cheater for 5.0 (Auto Specialties Smog Pump Eliminator Brackets: Bracket, Smog Pump Eliminator, Aluminum, Natural, Ford, Mustang, 5.0L, Kit) then plug off the holes in the back of the heads, and cap off the tube that goes into the cat. So other then emissions & state inspection the removal of the pump isnt going to effect the cat. Also the air goes in AFTER the O2 sencer so it wont throw a code on you. My 2 cents.
Keep Em' Twistin' Bob B.

Bronco Stables: 89 thru 96 / XLT / Eddie B / BR II

 

I'll get some pictures together of the stock system. The parts are all still there, but no longer connected to a belt. I'm working on the removal as I get time.

 

i thought smog pumps push fresh air before the cat but after the o2 to finish burning a rich mixture? This helps prevent the cats from clogging from the rich mixture but it does heat them up. not having a smog pump will make your cats run cooler(not as effective) and they will clog. i have gutted cats on my 89 but i kept the smog pump(even though it doesnt do anything for the cats). my 85 has it all blocked off and deleted. While the smog pump is "pumping" all the time the selector valve only pumps it to the cats at idle and warm up i believe.


ive also heard of people using them as superchargers but you would need several on anything bigger then a 5hp briggs.

 

There sposed to work damn good on lawn mowers....cept you need to run the mower lean? to keep it from poppin head gaskets.....hmmmmm heh heh heh

JR

 

So, making the gross assumption that were are referring to a non-modified 91 Bronco (gotta do this based on the screen name "mac-91"), the Thermactor system employs the Air Induction, Recirculation (A.I.R.) pump or "smog pump" for two reasons.

Introduce additional oxygen to the factory catalytic converter allowing it to heat above the temps achieved during the combustion cycle. This allows additional exhaust gasses to be burned off that cannot be in the normal combustion cycle. (Yes adding oxygen helps the temp rise because there is already enough heat present and when the oxygen is added, the gases that require the additional heat will ignite. Another source of combustion increases the heat).

Reason number two (and far more critical when you are dealing with the EEC-IV system) is that it provides additional fresh air into the exhaust ports in the heads for the same reasons and to help maintain the necessary oxygen levels in the exhaust so that the O2 sensor will function within the parameters it was designed for. Eliminating this input from the smog pump will adversely affect the operation of the O2 sensor and make tuning more difficult along with the fact that the system will no longer be able to control the flow of additional oxygen into the exhaust wich will effectively shorten the lifespan of the O2 (Oxygen) sensor. That odd contraption behind the passenger cylinder head with the hoses and vacuum lines known as the diverter valve handles the directing of fresh air from the pump to the cat and the heads. The TAB and TAD solenoids are the EEC-IV computer's (ECM) method of controlling this valve.

The problem with the arbitrary removal of PARTS of the system is the simple fact that they are so well integrated that it is impossible to remove any one without adversly affecting the rest of the system. Anyone who would argue this should try reading up on how the EEC-IV system really works.