TRayman

I have a 1993 F150 2 dr, 2wd, 4.9L I6, with the 5 speed M5OD transmission.
I suspect most of that does not much matter for my question.
In GA I am no longer required emissions testing. The truck needs a new exhaust. The muffler and pipes are rotted out and the manifold gasket has a leak.

SO I am thinking that it is time to pull it all off clean it all up new gaskets and everything from the manifold back.
I am wondering if it is a bad idea to remove the smog pump and seal up the port on the exhaust and remove the catalytic converter.
I know I am an evil human and I am solely responsible for the destruction of the environment.
Beyond that what are the implications for how the truck performs if I do this.
Is there some feed back to the computer that will be confused? Will the MPG drop to negative numbers or jump to 20?
If there is no compelling reason to do it, why do people do this?
The catalytic converter is relatively new and in good shape but if I leave it I need to leave the smog pump don't I?

Anyway I searched around and did not see much of a discussion about this so I am asking.
Thank you in advance for all your answers.

BLDTruth

First, when you say the catalytic converter is relatively new, does that mean you had it replaced with an aftermarket cat at some point? Because really its only the factory cats that need the smog pump - most modern cats do not need to be "warmed up."

Regardless of your state emission testing laws, it is a federal offense to remove any emissions equipment from a vehicle without replacing it. So prepare for the wrath of the FBI, EPA, and most importantly, the hippies.

So now that the disclaimer has been made - I pulled my smog pump off awhile ago when I got a new custom exhaust, along with all of the plumbing from the pump to the valves on back of the heads. You need to cap the vacuum lines that control the valves on the solenoids, plug/remove the pipe from the back of the heads to the exhaust, and plug the hole(s) in the back of the head(s) with bolts. And then you'll either need to hollow out the smog pump and use it as a dummy pulley, run a shorter belt, or buy a delete pully. Not sure on what you can do in the I6 because my experience is all with the 302.

It will have little to no effect on how your truck runs, what mpg it gets, etc.

TRayman

Great information! Thank you. If it does not change how it drives or MPG why bother to remove the stuff? Is it just to simplify the system and make it more reliable? The smog pup is just one more thing waiting to break after all.

I am curious because I hear about people removing this stuff all the time and I never knew why.
Oh and yes the cat was replaced a few years ago with an after market one.

BLDTruth

Usually people pull their smog pumps because they seize up and they don't want to replace them. The other reason is because they think that their level of freedom is inversely proportional to the level of emissions equipment on their vehicle, and ain't no gubberment agency gon' tell dem wut tuh do.

In a nutshell.

Steve83

There is no gasket anywhere on the factory exhaust system, so that's not leaking unless someone added one somewhere.


(phone app link)

There's nothing to simplify - the truck simply works best the way Ford built it. They didn't add parts to make it complex or unreliable. And if that's how you want to look at it, the whole truck is just waiting to break, so get rid of it now. But keeping it as close as possible to stock not only keeps the hippies & gubmint happy (whether you have inspections now or not); it also makes it run better, get better MPG, require LESS maintenance & repair, and costs about the same as paying someone to hack together something different/unreliable/illegal/inefficient. If you want to know more about what each (of the 4) emissions system does, read this article.

Incidentally...
The smog pump is VERY easy to repair:


(phone app link)

And it's also common & affordable to buy a reman. People just look for any excuse they can come up with to rip out parts they don't understand.

TRayman

Thank you for the information.
I have never really wanted to understand emissions systems because I have always thought of them as making the vehicle run less efficiently.
I have kept the truck stock because if it aint broke... but the exhaust is broke now so I am looking at what is best for the truck for functionality and reasonable cost.
Rebuilt smog pumps are about $100 but if I can rebuild it myself (as your link shows) that is cool and more cost efficient.

I had the cat replaced several years ago and I honestly do not know if they reattached the smog pump to it. I will have to look.

Steve83

That was true in the 70s & early 80s. But by the time your truck was built, they were helping, as that link explains.Maintenance of ALL factory systems.The last time I had to buy one, it was ~$50 - I'm surprised they've doubled. But they're still available in the $15~$40 range in junkyards.