Catalyctic Converter change- How to?

[yami]

Hi my friends

My 1999 Mazda Protege LX engine check light is on for a long time and I know it is because of its Catalyctic Converter which is badly clogged.

I want to change it but after searching in internet for parts, I got very confused. My mechanic works in his house then he asked me to buy parts online and take to him for exchange.

In auto parts web sites there are many different parts listed as Catalyctic converters. Like this one

I have no idea what exactly I need to buy.
Also please let me know if I should change Manifold too because here it is listed with catalyctic together and I was wondering if manifold gets clogged too.

 

[tweety2300]

Do a search for the non fouler trick. Easy to do and you can do it yourself

 

[Installshield 2]

I'm not completely familiar with the 1.6L exhaust system...but i'm fairly sure, like the 1.8/2.0L engines, it actually has 2 catalysts in the exhaust line.

How are you certain its 'badly clogged'?...for the most part, a catalytic convertor won't get damaged without other major engine problems...notably when an engine misses regularly, yet is driven extensively anyway. What check engine light code are you getting? Your mechanic should give you that information. Only one of the two catalysts is recorded by the ecu, which is usually referred to as a 'pre-cat'. That one is right on the exhaust manifold, very close to the engine, and is designed to heat up very quickly. The secondary catalyst is underneath the gear shift, basically. Its a bigger unit that will filter more once heated up, but heats up relatively slowly compared to the pre-cat. The secondary catalyst is not monitored in any way by the car's computer. So if you're sure you're getting a catalyst problem through the code being displayed, its most likely the primary cat...

I'm not sure of Florida's emissions laws...your link is for a universal catalyst, which are usually used to replace the secondary 'big' cat farther back in your system. exhaust shops can easily modify some piping to replace the entire mid pipe; housing the cat....but sadly...pre-cats are more difficult to replace with anything other than a specific one built for your car...and they are extremely expensive.

However, you have some options, depending on your emission laws and inspections in your area. For $4 you can remove that check engine light. It involves a set of spark plug non-foulers stepped together to effectively block the secondary o2 sensor (which is ONLY used to monitor pre-cat performance) ppm readings...but does not remove its 'warm up phase' (what happens when an O2 sensor is tucked away and not installed in the exhaust)...i've used this for over 100,000 miles...no problems...but i used it because of installing a header that removes that pre-cat entirely.

So thats the other part. The non-fouler with a header is the cheapest way to 'replace' that catalyst...otherwise a dealer will charge close to $1000 for that cat, and i've never had much luck sourcing them at aftermarket websites. Even when you find one, its usually OE and still extremely expensive.

It all falls back to the code you are getting from the computer...and how you are sure the cat is badly clogged. Is gas mileage terrible? Does the engine run poorly compared to before?

 

[yami]

Thank you my friends
@Installshield 2: In fact I do not care Check Engine Light is on. The problem is car looses more and more of its power specially when it begings to move from stop (like behind red light). I push throttle and RPM goes up to 3000 but car accelerated far less than what is expected from 3000RPM in first few seconds. Of course after getting into speed I do not notice less power. Seems (what I and mechanic assume) catalyctic converter is clogged then the first moments of moving and acceleration engine wants to push lots of smoke thru it which of course does not go thru that easily. I have Cat error code also.
Engine works very smoothly after getting into speed or while being stopped then I really have no idea if something is wrong with it. It has 130,000 Mile on it.
I would appreciate all your second thoughts on this case after reading my post.

 

[tweety2300]

Is it an auto or manual?

 

[yami]

Is it an auto or manual?

Automatic
Also I found this Pre-Cat. What do you think so? HERE

 

[tweety2300]

So when you hit the gas it goes to 3000 rpms? Or does it just not make any power untill 3000 rpms?

 

[yami]

So when you hit the gas it goes to 3000 rpms? Or does it just not make any power untill 3000 rpms?

Engine works smoothly when car is stopped or after getting into desired speed and keeping up with that. Main problem is when you need more power in short time like moving from stop. When I push throttle car begins moving but not that powerful and fast expected, I push throttle more and RPM goes up (I don't push it more than 3000RPM but if I do, it goes) but still car does not get expected acceleration. It is like (relatively not exactly) it does not matter how much you push throttle, engine produce power little by little.

Good car when you push throttle: (numbers symbol of amount of power you get after pushing throttle gradually)
1 -- 2 -- 3 -- 4 -- 5 -- 6 -- 7 -- 8 -- etc

My car:
1 -- 1 -- 1 -- 2 -- 2 -- 2 -- 3 -- 3 -- 3 -- 3 -- 3 -- 4 -- 4 -- 4 -- 5 -- 5 -- etc

 

[tweety2300]

I think you have a normally running protege lol. Keep in mind your dealing with about 65 whp which my brothers scooter is making close to that

 

[yami]

Honestly I am not sure if I am right. Maybe you are right and I expect more from it but the point is I feel it was somewhat better few month ago, I mean about acceleration from speed zero.
Is there any non-destructive way to check CAT and O2 Censor to see is they are working well?
What are other reasons that engine fill up to 3000RPM at the moment of moving from stop but does not produce enough power?

 

[Jspeed17]

Honestly I am not sure if I am right. Maybe you are right and I expect more from it but the point is I feel it was somewhat better few month ago, I mean about acceleration from speed zero.
Is there any non-destructive way to check CAT and O2 Censor to see is they are working well?
What are other reasons that engine fill up to 3000RPM at the moment of moving from stop but does not produce enough power?

Yami, it is very possible to have a clogged cat causing less power. BUT, as Installshield said there is usually a cause to why they break up inside and then clog the exhaust flow. This may have been from a previous situation like the engine skipping/misfiring/running rough that you may have already had fixed!!!

A "ghetto" way to check if this is your problem is to pull the primary o2 sensor out of the manifold, and go for a ride. See if it accelerates better.

In a clog situation such as this where power is lost, i recommend changing both the pre-cat(manifold cat) and the post cat(under the car), simply because if the pre-cat broke apart, exhaust gasses are going to push the broken platinum pieces into the post cat.....you may never get all the sediments out of the post cat for optimum flow
Hope this helps!

 

[yami]

Honestly this car looks like driven very gently. I think misfiring in long run caused clogging because previous two owners it had both never changed timing belt (which I changed) and seems they were just believing in driving car gently but no maintenance.
I am going with CAT change then two more questions:

1- Do you know reliable site or store to buy both CATs and parts? I really cannot afford something like magnafold, etc. I am not racer! As much as it gets fixed to normal condition it is a lot for me. I do not need Tuning!
2- Should I change O2 Censors too? They are two as far as I know?

 

[Installshield 2]

here, bud...Looks like over the years you can find some aftermarket suppliers for the pre-cat...just a few years ago, this wasn't the case...

I'd recommend a brand name part like bosal (they are the OE supplier for many vehicles, but not mazda as far as I know), over something off of ebay like 'cat katz' or whatever that was haha.

That should bolt right into your stock system...but like tweety said, its a 1.6L with an automatic...the thing will do 0-60 in like 12 seconds...I'm not making fun of it, just pointing that out in case you are a new owner of it or something, thats all.

Also, yeah its not a bad idea to change both o2 sensors also, assuming you want it done right. If something caused a catalyst(s) to fail, chances are the sensors aren't in the best shape either. You can find both of them from that place, i've dealt with them a lot recently, and they are pretty quick to get you your parts. but any decent online retailer should have that stuff.

 

[Jspeed17]

Usually you can get replacement cats at any reputable parts store like NAPA, or O'Reilly's, even Auto-Zone or Advanced Auto Parts....not sure what major auto parts stores are down south...lol

O2 sensors aren't that cheap or needed in your case, but your car may run better if you replace the "upstream/manifold" o2 sensor with a new one

I check rockauto.com, and they seemed to only sell the manifold cat

 

[yami]

Thank you very much everybody. I think now I know what to do

 

[tradosaurus]

Well both O2 sensors will run you about $140.00. A catalytic converter will run you about $125.00 (on ebay).

The non-fouler trick seems to be free so why not try this first instead of throwing money at the problem?

 

[yami]

OK, I am returning from my mechanic. Weird story!
1- He says these cars (1999 Mazda Protege LX 1.6L) does not have rear/post Cat?! [I don't know, maybe he really means it or he means it is not important to change it]
2- He asks almost $600 for replacing pre-Cat :/

Now I just assume I take it somewhere else and they charge me less for replacing both Cats and O2 censors (which he says are not good). It is going to cost me not less than $700. I really do not think this $2000 car worth such a costy repair. I do not know but as the problem is not that emergency, I may decide to drive it as much as I can change the car in future or it breaks down and I sell for cheap. Really stupid repair costs

About Fouler trick, I dont know how it helps (I am not that geeky), specially when partially clogged Cat exist in exhaust circuit.

I was thinking about those eBay Cats for around $120 for pre-Cat and $70 for rear/post Cat. I know I cannot do the rear one as it needs welding but how about pre-Cat, is it easy to do at home? Are they really worth the money and work? (I mean they just let the smoke flows away, we do not need more than that).

 

[Jspeed17]

Yami, i am a mehcanic, and i also own a 2000 protege DX with a 1.6 engine....any cat-converter replacement is expensive on cars...MAYBE it's possible that the '99 model doesn't have a post cat....what you can do is replace the pre-cat (manifold cat) which will fix your car, and cut the post cat off and have a straight piece of pipe welded in place of it, since the cars' computer doesn't know about the post-cat (no oxygen sensors after it)....if you buy the part, i don't see why your mechanic buddy should charge you more than $150-$200 to change it

Tradosaurus--Anti-foulers only will get rid of a check engine light....won't fix a clog

 

[tweety2300]

You can always just take an air hose and blow it out, or gut it an use the non fouler for cheaper options

 

[yami]

Thanks Jspeed17, thanks tweety2300.

I may buy this to change it by myself but, ooops, I really don't know its going to be enough easy or not.
Specially because O2 censor is required for optimum performance too. Oh my god, why stuff are complicated :/