Catalytic Converter Replacement

[Weasels]

Anyone ever done this themselves? Want to replace old cat cuz it is getting pretty "chatty". Just wondering if it is really just a bolt on? Any wires I need to know about? Thanks for any input big or small.

 

[Blacksheep Josh]

if i recall correctly, in 93-94 explorer, there are two 02 sensors, both of which are BEFORE the catalytic converters. so i believe there are no sensors/wires you'll have to worry about. as for replacing them, i'd recommend goign to an exhaust shop and letting them doing it, there's a lot down there, and you dont' want to get stuck halfway.

unless your'e confident you can do it 100%, have it done professionally. buy the catalytic converter yourself, and have them install it. just my opinion though, i messed with my exhaust once, and i'll never do it again.

oh yea, we have 2 catalytic converters i believe. so you might need to figure out which one it is.

 

[Mr. Logger]

I'm with Josh. I'm quite sure that OBD-I cars only had O2 sensors for the monitoring/adjusting the air/fuel ratio. None to do with the cats.

 

[Blacksheep Josh]

Yeah, from what I recall, the 91-91 has one 02 sensor, and then in 93-94 they added another so you had one 02 sensor for each side of the manifold.

 

[Willard]

Yeah, from what I recall, the 91-91 has one 02 sensor, and then in 93-94 they added another so you had one 02 sensor for each side of the manifold.

That is correct. Also, yes, there is technically two catalytic converters, but they are one unit. Might as well replace them anyways.

If you want it to be on the cheap, score a universal catalytic converter with correct size piping and retrofit it.

 

[Blacksheep Josh]

Or install a highflow catalytic converter with a flowmaster exhaust, lol.

 

[Shen2187]

Well, looks like you got your question answered. Just want to say (for others that read this), Please DO replace it. Too many environmentalists complaining about everything already.

Speaking of exhaust, I should take a picture of my "awesome" muffler lol. Imagine that it was made of wood, and I put a colony of termites in it.... Swiss cheese anyone?

(EDIT) By the way, Nice tie Josh!

 

[Blacksheep Josh]

Swiss cheese anyone?

(EDIT) By the way, Nice tie Josh!

Mine used to look like that... it has a horrible buzzing sound, I think it was original, cause about half of the shell on the back half was completely missing, you stick your arm into it...

Thanks! That was probably 2 years ago now? I'm very picky about my pictures, but the ones that come out good are good for a while.

 

[Weasels]

Wow. Thanks for all the response. I think ill take ur advice Josh and buy it myself then take it to an exhaust shop. Maybe have 'em put on a flowmaster 40 delta if its in there anyway its the original one with 260,000+ miles on it so its held up and done its job. Just can't stand the noise at 1500 rpm anymore. LOL. And here in Cali everything goes to hell fast if you try to get around using a cat. Any clue on a price anyone? Thanks again.

 

[Blacksheep Josh]

Any clue on a price anyone? Thanks again.

really depends where you shop and get everything. i believe for 140 (somewhere in that area) i had a custom exhaust from the cat back installed. it's 2" piping with a flowmaster 40 muffler. my old piping was just rusted out.

hopefully before spring i'll have it upgraded to 2.25 or 2.5 inch piping the whole way.

 

[Weasels]

really depends where you shop and get everything. i believe for 140 (somewhere in that area) i had a custom exhaust from the cat back installed. it's 2" piping with a flowmaster 40 muffler. my old piping was just rusted out.

hopefully before spring i'll have it upgraded to 2.25 or 2.5 inch piping the whole way.

what is the advantage to 2.25 or 2.5 inch piping? Sorry for the rookie question.

 

[Blacksheep Josh]

what is the advantage to 2.25 or 2.5 inch piping? Sorry for the rookie question.

in all honesty, i have no idea.

but i'm looking to increase the volume of my exhaust a little bit, and bigger piping is what i'm told will help achieve this. also may help with performance a little bit, by allowing the exhaust to flow more freely. but to big is bad, you just have to find the balance. but i keep reading/hearing 2.5" is the biggest you should go. 2.25" is most likely what i'll do, slightly bigger then what i have now, so i'm assuming the volume will be slightly louder, which is what i want.

 

[Weasels]

in all honesty, i have no idea.

but i'm looking to increase the volume of my exhaust a little bit, and bigger piping is what i'm told will help achieve this. also may help with performance a little bit, by allowing the exhaust to flow more freely. but to big is bad, you just have to find the balance. but i keep reading/hearing 2.5" is the biggest you should go. 2.25" is most likely what i'll do, slightly bigger then what i have now, so i'm assuming the volume will be slightly louder, which is what i want.

Thanks for your time with this stuff. Im trying to learn as much as I can cuz it seems like everyday something goes wrong. lol. Starter just went out this morning.

 

[Blacksheep Josh]

Just do me a favor, take whatever I say with a grain of salt. Anything I know of and have learned about Automobiles (mostly explorers) is because of this website. Read as MUCH AS YOU CAN, you'll slowly start to absorb it. So I myself might be wrong in some instances, but thats' what is nice about the site, someone else who knwos for sure can alwasy chime in and correct where needed.

As for the starter, I remember having to replace mine last year about this time... Make sure it's not the battery terminals, the battery cables, and also the starter solenoid on the firewall. Those three things can also cause the starter not to go, in my case it was the battery cables and solenoid, but I went ahead and replaced the starter because it was so worn down.

 

[Weasels]

For once I'm actually pretty sure its the starter. I just put in a new battery, terminal hook ups, and the wires were replaced in April. I also put an alternator in last Sunday and I've been checking the battery voltage with a multimeter every other day to make sure I did it right. So far so good.


And I'm right with you about reading EVERYTHING that I can. I'm very interested in the Xs and am glad to read about things I dont know about. Six months ago I couldn't do anything with it and now I am slowly learning how to do things myself, all thanks to this site. It really is a lifesaver for a lot of things!

 

[Shen2187]

The size of piping for your exhaust dictates how well the exhaust exits the combustion chamber. The key term you may or may not have heard tossed around is "Back Pressure".

Back Pressure is the term used to describe the compression of the exhaust flowing through the piping.

High back pressure causes the exhaust to move slowly through the exhaust system.

(EDIT: An aftermarket kit is specifically designed to boost power by providing the optimum amount of back pressure. That's why exhaust kits are a bit on the expensive side.)

There are many things that cause high back pressure, Piping diameter, many tight bends in the piping, restrictive catalytic converters and mufflers.

Factory exhaust systems tend to have all of the above.

A high-flow exhaust system will generally be a larger diameter, have less bends or smoother bends, high flow cat's and high flow mufflers.

So why go through all of the trouble to lower back pressure?

Less back pressure means more air flow, more airflow means more air going into the engine. When there's more air going into the engine, the Engine Control Unit (ECU - The little computer in your passenger side kick-panel) increases the fuel flow. More fuel and air makes more power.

An engine putting out 100-300hp (like our 4.0's) should have exhaust piping sizes between 2.25 and 3.0". Most people go with 2.5" because it boosts your HP and Torque.

TADA!

(EDIT: As for volume, a larger diameter will be louder because there is more room for the sound waves to bounce around. High flow mufflers also tend to give more volume because many of the baffles that lower the volume are removed to provide better flow, this also applies to catalytic converter [AKA Cat's]. For example, Flowmaster specifically designs their mufflers to give a specific sound by arranging the baffles in a certain way. That's why they have so many different ones, each with a different sound.)

 

[snelson2674]

Hello,

How long does it take to replace both catalytic converters if you have the direct fits for a 99 explorer eddie bauer?

Thanks.

 

[Blacksheep Josh]

Hello,

How long does it take to replace both catalytic converters if you have the direct fits for a 99 explorer eddie bauer?

Thanks.

I have no idea. If you check over in the Second Generation Explorer forum I'm sure you'll find plenty of answers. Nice hijack, btw.

 

[mowermechanic]

punch a hole, and vacuum excess, but of coarse you wouldn't be driving that on state roads

 

[SwaintaN]

Or install a highflow catalytic converter with a flowmaster exhaust, lol.

that is what im doing! BTW installing a new cat, you have to buy the one with two made onto it... it can be a ***** if you live in a bad rust state!! i looked at mine while doing the ext pipe to tail pipe, and they are rusted on TIGHT!!!! so they might need warmed up with a welder to suck in the pb blaster, so its not hard, you need light, jacked up, and tools, and for me, its a case of Corona Extra and alone time from the kids! sorry started to wonder and chat, mine, on the 93x is two bolts into the ext pipe and then two spring bolts onto the main pipe, best advice, take off the ext pipe as well, so you can slide the cat convt out the back instead of taking off the guard that protects it