Catalytic Converter replacement

joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:40 am

I replaced my catalytic converter, hoping it will cure my recurring P0420 CEL. Here are a couple of pics in case anybody else ever has to do it. It was pretty easy.

Before starting on the real steps, jack up the car and support it well. I can't stress enough how critically important it is to be sure that you have the car raised in a completely secure manner. I don't want to hear about any genvibers who were crushed to death working under the car because they had some half *** support thing that failed.

I jacked up the front paseenger side wheel, set it back down on a cinder block, but also had a jack stand under the frame, and a jack just making contact. I then shook the car as hard as I could side to side, front to back, up and down, hard, to make sure it wasn't going anywhere. I suppose you should probably disconnect the battery any tine you are going to work on the car. I didn't, because I had my laptop playing through the car stereo while working on the car.

First real step is to remove the O2 sensor. There are two of them, one plugs into the exhaust manifold, and the other into the pipe between the two catalytic converter stages. The book said I should remove both, I didn't bother the one in the exhaust manifold. The second one screws into the pipe under the car, the wires goes through a rubber grommet in the left front side of the front passenger floor. The first step it to disconnect the electrical connector, so pull back the carpet, and you'll see the O2 sensor wires and where it connects on the side of the center console Disconnect the connector, and then push the grommet out from the inside, feed the wires through the hole

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:41 am

The O2 sensor is probably some metric size, but a 7/8" wrench fits it great. I only had a box end, so I slid it along the wire,pushed the grommet through the wrench, to get the wrench up to the O2 sensor. Unscrew the O2 sensor.You can leave the wrench on the sensor, you won't need it until you are putting the O2 sensor back in the new pipe.

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:42 am

Next, remove the two bolts that attach the catalytic converter to the exhaust manifold, and the two bolts that attach the catalytic converter assembly to the muffler. These bolts hold a spring in place, and are designed so that the bolts bottom out, and springs maintain the pressure that holds the pipes together. The bolts are 14mm.I had to use a couple of extensions to be able to reach the bolts on the exhaust manifold, the muffler side was easier to get to, but one of the bolts on the muffler side was really tight. I used some WD40 on it, that helped some.

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:42 am

There is a metal bracket, I am sure it serves some purpose, but I have no idea what. It is in the way, however, and has to be removed to get the pipe assembly out. These two nuts take a 12mm tool

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:44 am

Now the only thing holding the pipe in the car are two rubber hangers. The pipe is pretty well balanced on these. There may be some nice trick to get these rubber hanger things to slide over the little pipes, but I just muscled them over the bumps on the end. Once you get the first one off, the pipe assembly will want to spin and fall some. After you get them both off, the assembly is free and can be slid out from under the car.

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:45 am

There are two gaskets, one between each connection point. The one on the exhaust manifold is larger, and will stay on the exhaust manifold when you remove the converter. The other one between the assembly and the muffler is smaller, and will stay on the converter assembly when you take it out.These gaskets are like rings made of compressed steel wires with some sort of ceramic or graphite stuff to fill in the gaps. It crumbles farily easily, and the wires inside are damn sharp. Cross section is flat on one side, beveled on the other.When I bought the replacement converter from the Pontiac dealer, they told me they didn't have the gaskets, but I could pick them up from any auto parts store. They lied. A couple of the auto parts stores thought they had them, but they definitely didn't match what came off the car. Most of the auto parts stores knew they didn't carry them. I boogered up the rear gasket a bit taking it off (that's how I know they crumble easily) but at that point I had no choice but to reuse them. I will give it a little while to see if the spring loaded action of the assembly seats things ok, but I may need to find some replacements somewhere. Maybe Toyota.

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 8:45 am

An important thing to check is to compare the new part to the old part. Here are the two converters side by side. Perspective in the pic makes the new one look longer than the old one, but they were an exact match. At least when you drop about $500 for part, tax and core charge, you walk out with a big part for the money.Installation is pretty much the reverse of removal. - Put the gaskets on the exhaust manifold and the back end of the converter assembly- suspend the asembly on the rubber hangers- replace the mystery bracket-screw the assembly to the muffler - screw the assembly to the exhaust maifold- put the O2 sensor in the pipe- feed the O2 sensor wires up through the floor, put the grommet back in place, connect the wire, restore the carpetMaybe an hour's job. Took me a lot longer, because first I stopped to take pictures, and also because I spent a lot of time in another vehicle running around trying in vain to find the gasket rings, and also because I accidentally kicked one the of the bolt/spring things and spent way too long looking before I found it.

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joatmon · Post by **joatmon** » Sun Mar 26, 2006 9:49 am

I have a 2003 Base Vibe. GM parrt number for the catalytic converter is 88969126. THe GM list price for this is $442, which is what I paid. Plus 5% Maryland Sales tax. Plus a $45 core charge, but I'll get that $45 back when I take the old converter assembly back to the dealer.I checked GM Parts Direct, and the price was a bit better after shipping, but I doubt I would bother to pay to ship the old one back to them to get the core charge back so the price was close enough I just bought one from the dealer. The GM dealer I bought it from said that the converter was one of the parts that GM tells the dealers to stock, that's why they had one to sell me. None of the exhaust shops near me had anything to offer, they said they'd be happy to put it in but would have to buy the part from the dealer. Toyota wants about $1100 for the converter assembly. It is too early to tell what effect this has had on the car. I have driven it some, to burn off the protective oil and my WD-40 overspray. I used the scangauge (see scan gauge thread) to clear the CEL, and it hasn't come back yet, but time will tell if I dropped $500 for naught. Now, I know this is completely subjective and probably wishful thinking, but it sure seems like the car has more power than it did before the replacemnet. The old JBD instrumentation indicates some power gain anyway (joatmon (removed) dyno). This would mean that there had been some performance loss over time, gradual enough I never noticed. Then again, it could be me looking for some improvement after dropping so much money on the part. I just hope this fixes the P0420

tnpartsguy · Post by **tnpartsguy** » Sun Mar 26, 2006 9:53 am

I'm a bit confused abotu one thing, do you have over 80K miles on your car? Or did the recall not apply to you? I'm just trying to figure out if the CC could have been warrantied in some way, shape, or form.

joatmon · Post by **joatmon** » Sun Mar 26, 2006 10:04 am

I have 106K miles on the car, so I am beyond the special extended 80K miles warranty on the converter. My CEL came on at some point, after I passed the 80K miles. Definitely, if I had less than 80K I would be hitting up the dealer for warranty. The part is too expensive to ignore warranty coverage. Some of my P0420 stuff is discussed in http://forums.genvibe.com/zerothread?id=19728 Looking in that thread I posted I first had the CEL aon 11/3/2005. I checked my gas records, and on 11/3/2005 I had 93400 miles on the car.

Post by **NSimkins** » Sun Mar 26, 2006 11:14 am

Great write-up joatmon! Thanks for taking the time to document and photograph the process. I'm in the P0420 club as well so your end-result will hopefully be a positive one.

joatmon · Post by **joatmon** » Mon Mar 27, 2006 9:22 am

well, if toyota cost was $1100, I still got a deal. Don't matter now, money's spent. Thanks though

joatmon · Post by **joatmon** » Thu May 25, 2006 1:04 pm

seems like the converter replacement has had some positive effect on my gas mileage

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Post by **NSimkins** » Sat Jul 22, 2006 8:55 am

joat, do you have any updates to this issue and your possible solution?

joatmon · Post by **joatmon** » Sat Jul 22, 2006 9:27 am

No return of the P0420, and 12K miles since the converter replacement, average 37.1 mpg for those 12K miles, so I'm satisfied.How about yours, are you still throwing the CEL every now and then?

zionzr2 · Post by **zionzr2** » Sat Jul 22, 2006 9:30 am

when i had my CC replaced due to Rotten Egg syndrome. I did notice a marked and sustained increase in my MPG. My charts look similar to joat's even though i dont i have it marked on a chart i do have seperate excell sheets before and after cat and am averaging 1-2 mpg better after new cat.

Post by **NSimkins** » Sat Jul 22, 2006 9:53 am

Quote, originally posted by joatmon Â»How about yours, are you still throwing the CEL every now and then?Yup, about once a month or so it returns after being cleared using the ScanGuage. I've noticed it appears less frequently now that it has been warmer compared to every couple weeks during this past winter (when it first appeared).Did you happen to get any part numbers for the O2 sensors either from AutoZone, Toyota, or GM?If anything, I'll make this a pre-winter project and follow your steps on replacement.

joatmon · Post by **joatmon** » Sat Jul 22, 2006 10:05 am

Quote, originally posted by NSimkins Â»Did you happen to get any part numbers for the O2 sensors either from AutoZone, Toyota, or GM?It seems like at some point I did look up the Bosch part numbers for the O2 sensors, and posted them in http://forums.genvibe.com/zerothread?id=22228. Autozone sold OEM and generic ones, the difference supposedly was that the cheaper generic ones did not have the connector on the end of the wires, you had to cut and splice with the old O2 sensor. I paid more for the plug'n'play version.I still have my original O2 sensor, it is probably still good, although I haven't put it back in since the cat replacement to find out. PM me an address if you want it, to see if you get any different symptoms. We both have base non-AWD vibes, so it should fit no prob.

Post by **NSimkins** » Sat Jul 22, 2006 10:21 am

Quote, originally posted by joatmon Â»It seems like at some point I did look up the Bosch part numbers for the O2 sensors, and posted them in http://forums.genvibe.com/zerothread?id=22228. Autozone sold OEM and generic ones, the difference supposedly was that the cheaper generic ones did not have the connector on the end of the wires, you had to cut and splice with the old O2 sensor. I paid more for the plug'n'play version.Thanks.. I should have Searched a little better... That is the info I needed. I think that if I end up doing this, I'm going to replace the cat's and both sensors and be done with it (hopefully). Quote, originally posted by joatmon Â»I still have my original O2 sensor, it is probably still good, although I haven't put it back in since the cat replacement to find out. PM me an address if you want it, to see if you get any different symptoms. We both have base non-AWD vibes, so it should fit no prob. Thanks! I'll let you know what I end up doing.

1fstramand1slovibe · Post by **1fstramand1slovibe** » Thu Dec 07, 2006 6:04 am

dont mean to steal the thread but i have a quick question... when i had my custom exhuast done i had the second cat cut off because it is behind the second o2 sensor and i didnt think it would bother any readings(which it hasnt) anyway my question is does anyone make just a single cat that bolts on behind the header....

Petrucci914 · Post by **Petrucci914** » Fri Apr 13, 2007 12:58 pm

I'm going to replace the cats with just one. I'd probably want to put that before that O2 sensors then, eh? Is that Pre-Cat any different than a cat I might buy. I don't want to replace the first one and have CELs because it detects it as being different even though it's still doing the job.

DavidPIL · Post by **DavidPIL** » Wed Apr 25, 2007 4:38 am

Hi Petrucci,I know there has been many discussions about the 1 cat vs. 2 cats thing but when I had my exhaust done at a reputable place, I asked about the 2 cats. The place said that the first cat wasn't a cat, it was an expander. I'm still not convinced since it looks just like the 2nd cat but with the mounting flange thing.If you find out more on this, let me know. Apparently an expander is like a gutted resonator, it's supposed to help increase HP. I researched this but only found links to them on motor cycles. If this is not an expander but a true cat then I will also be having mine removed. I bought a high flow cat... There is no sense in having a high flow cat after a restrictve cat.Dave

Petrucci914 · Post by **Petrucci914** » Thu Apr 26, 2007 2:37 pm

The following reply was posted by Lancer:Quote, originally posted by drunkenmaxx Â»sell the SC and get your money's worth out of that tranny! do it now!If I had $4 grand lying around I would! The s/c is only worth maybe half that. I stopped in yesterday to drop my car off again. They had already put the turbo into another celica gt-s.Petrucci,The first cat IS a cat. Not just a hollowed out expansion chamber. It's to help with emissions during a cold start. That's why it's closer to the engine than the other main cat (so it heats up and starts working faster). If it was just a hollow shell, then mine wouldn't have melted and emptied into the second cat. I had the first cat cleaned out and the second was ruined so it was removed and replaced with a straight through muffler. NOW I have a highflow cat installed almost a foot down from the original spot. The 2nd O2 sensor was also extended. Then there's a 18" resonator, band clamp for racing at the track (just remove the rest of the exhaust ), then a big oval muffler and my old Borla exhaust tip. The tip is just a tad bigger then the pipes! The whole thing is huge! They "didn'thave time to finish it today," again. So tomarow I should get it back and it better sound perfect!Speaking of hollow shells. Found out that the first muffler they tried was just a hollow shell. No baffling or packing at all! No wonder it was so loud! I got a pic of the first set up with the round staight through muffler. But my camera and 'puter aren't on good speaking terms.---------------there's your answer!

furrydogs1 · Post by **furrydogs1** » Wed Jul 18, 2007 11:49 am

Joatmon,Is your catalytic converter still running fine and has the CEL stayed off? I was going to replace the cat myself using your great pictures as a guide but after talking with a mechanic he thought that might be a bad idea. His rationale was that "CAT's just don't break, something causes them to break". He was inferring that I could end up replacing the CAT only to have it break down again b/c I didn't fix the "real" problem. Based on your experience do you think I should let them try and diagnose or should I just go ahead and replace the CAT? BY the way, I continue to have the CEL on the code was the infamous P0420.

Sublimewind · Post by **Sublimewind** » Wed Jul 18, 2007 9:45 pm

Quick question and a possible answer. Are you guys runing headers? The reasion i ask is, i'm getting PO420 on my Subie and while i DON'T have headers on it, the factory manifold is very similar to a header, just doesn't have the nice bends and all.... Anyhow, many people have mentioned to me that, because i have the heat shields off the stock header, the cat is not getting HOT enough and basicly "going out" I'm thinking i have a clogged cat now due to this, which seems logical, if it is not burning off the carbons and gasses comming from the motor, it's just building up...

b03matrix · Post by **b03matrix** » Thu Feb 07, 2008 4:33 am

Hello Joatmon,I have a 2003 base Matrix, 5 sp.The catalytic converter for Base Vibe and base Matrix are they the same (part # 88969126)?My Matrix has the same code P0420 and the dealer ask for $1400. Thank you,BN

joatmon · Post by **joatmon** » Thu Feb 07, 2008 11:07 pm

I am reluctant to answer, since I have been wrong more that right here lately.It seems that since I started this thread, the general concensus has been that buying a stock replacement from a dealer is a waste of money, and that the better solution is to get a muffler shop to weld in an aftermarket converter. I have never had that done, so I can't really say. It would probably be worth the time to stop into a Midas, Meineke, or some other local exhaust place to get a "free estimate" Also might be worth checking in some local tuner shop to see what they can offer. On your question about whether the Vibe piece will fit a Matrix (same year, tranny, etc) I guarantee nothing, but my gut feeling is that it should. When I was looking for one, if the prices were swapped where Toyota was charging under $500 and GM was charging $1100, then I would have bought one from Toyota. To me, it would be worth the gamble on what I expect would be tolarably low risk, assuming that I could return the part if it didn't quite fit, even with a restocking fee. I'd find out what price you can get one from a GM dealer. Toyota dealers seem to want a VIN before they can talk about a price, but GM dealers don't seem to, you'd just need to tell them it was for a 2003 base vibe 5 speed. See what price they offer, and then tell them it's for a Matrix, it should fit, but if it doesn't, how much would they charge to take the part back. It's failry straightforward to replace it yourself, if you've got the time, tools, and space, and buy the stock part from a dealer, that can save some over the labor cost of a dealer install. If you go for a non-stock solution, most of us wouldn't attempt to weld in an aftermarket converter at home, but would pay someone to do that.I should also be clear that I replaced the cat, and that's what it took to cure my P0420, but there are other possible causes for a P0420. I'd say it's likely the cat, but there is additional discussion in http://forums.genvibe.com/zerothread?id=19728 Just want to have covered that in case you replace the cat and still have the P0420. Welcome to genvibe, sorry about that cursed P0420, let us know what you end up doing to get it fixed.

fss106 · Post by **fss106** » Wed Apr 14, 2010 10:43 am

is there a good way to pull up the carpet in the front passenger side? or is it all muscling and fingers crossed that you don't booger up the plastic rivets holding it down?

epcIII · Post by **epcIII** » Wed Feb 02, 2011 11:13 am

Amen!I'll be doing this soon too. My mechanic wanted to charge $800(not outrageous, but still don't want to pay it) to replace mine, but I'll do it myself and save the $$$.

Piggy · Post by **Piggy** » Wed Feb 16, 2011 5:39 am

Hello, (first time poster) I'm starting to get the sinking feeling I'll need to do this soon. Replaced the O2s and cleaned my MAF, CEL came on 20-30 miles again after each and today the exhaust smelled more rich than I've ever had. I'm guessing with 182+++ it will need it soon anyway and to get to my point;The Autozone part looks to be less complete than your OEM in the pics. I read that the inlet uses the flange, outlet clamps... Spec sheet from autozoneI may just not be getting it, but from the looks of it I don't think I can do this with just my wrenches and some PB Blaster. I haven't bought the part but I'm suspect if this is something I can do or if I should take it in.Any thoughts or suggestions?

wallyuwl · Post by **wallyuwl** » Sun Mar 20, 2011 6:17 am

PiggyI also have the dreaded p0420. I've found online that using a spark plug anti-fouler with the exhaust O2 sensor can fix the problem in most cases very cheaply. But I want things to be perfect with my vehicles, so I'll probably be installing a new cat in a couple months, along with O2 sensors, an oil change, blow motor and blower motor resistor. Make a day of it. The AutoZone part you linked to is kind of expensive, and you would need a resonator as well. I'm looking at this as a replacement: http://www.autopartswarehouse....ellerI've found a few cheaper, but this seems to be a good company and it has a good warranty.

bassplayaz06 · Post by **bassplayaz06** » Sun Mar 20, 2011 8:00 am

why does the GT have 2 O2 sensors but the base only has 1?

wallyuwl · Post by **wallyuwl** » Sun Mar 20, 2011 8:16 am

base has 2 total.

Piggy · Post by **Piggy** » Thu Mar 31, 2011 12:10 am

Thanks for the info wallyuwl, I guess I'm like you. I'm too ocd to go the easy way... and I just realized I put almost 5000 miles on since I posted a month and a half ago....

wallyuwl · Post by **wallyuwl** » Mon Apr 11, 2011 7:09 am

Joatmon,I sent you an IM. i don't know how it works if the other person is offline. I can't seem to figure out if this forum has a PM feature. I started to replace the cat, but decided to quit while I was behind. It is raining, and cramped in my garage. So I decided to wait for another day.But, to make that other day easier, I had a couple questions about the catalytic converter replacement procedure.1) how exactly did you raise and secure your vehicle? Did you just raise the passenger side wheels, or did you raise the whole car? I've got one pair of Rhino Ramps, and a jack and a set of jack stands to work with.2) What tools exactly did you use? I've got a basic tool kit with sockets and ratchets, and a breaker bar. I'm most interested in what exactly you used for extensions to get off the bolts attaching the converter to the exhaust manifold. But the other tools you used would be helpful, too.Thanks for your help.

joatmon · Post by **joatmon** » Sat Apr 16, 2011 11:10 pm

I've been crazy busy at work and haven't had time to check the site for a while. IMs get displayed the next time the user logs in. My preference is to answer in the forums anyway, in case either someone else has similar questions, or someone else can answer the questionsThe entrance to my garage is like a ramp, about half a vibe long, so I probably just parked with my front wheels at the top, gives clearance underneath, with all four wheels on solid ground. Since you've got a set of ramps, then just drive the front wheels up onto the ramps, that will probably give you enough clearance to work under there. Do the other common sense things for when woking under a car, such as setting the parking brake and keep it in gear/park, chock the wheels, etc. Be safe, none of us wants the manner of our death to qualify for a darwin award. looks like I desribed how I jacked up the car in the first post. looking at the pictures, I can tell it was fully inside the garage, not on the front apron2. It's been five years since I did that, not sure exactly what tools I used. Based on the tools I have, I probably used 1/2 drive stuff. I've got a couple of six inch extensions, a two incher, a u-joint, 9" and a 15" ratchets and a good set of 6 point sockets. If it dries out enough today I can go crawl under there and see what it takes. Sometimes the biggest challenge to working on a car is finding the right combination of tools for a particular task. On some vehicles solving how to disconnect an electrical connector can be frustrating. Once I had to remove the door lock cylinder from a Ford ranger, the instructions said to unhook the conecting rod from the lock. I spent four hours trying every combination of anything I could find to do that, finally gave up and made a tool. Now that I have that tool swapping the door lock in a Ranger is about a five minute job. You shouldn't need to make anything special to do that cat swap, maybe just enough extensions.

wallyuwl · Post by **wallyuwl** » Sun Apr 17, 2011 1:16 am

Thanks for the reply.Last weekend after I changed the oil I jacked up the back end of the car (front end was on jacks). It was pretty tight for me (I'm not small), and in general I just didn't "like" being under the car when it was totally in the air. So I found a local exhaust place that installed it for $120 total. I was happy with that and they did a great job. With all the new intake manifiold gasket, throttle body "spindle" (forget the name of it) cleaned (and new gasket for it, and main TB gasket), PCV cleaned (didn't need replacing), new VVTi filter, new air filter, oil change (Synpower), new O2 sensors, and new cat, the vehicle has never run better in the five years we've had it. Due for coolant and transmission flushes about this time next year. Today is replacing the blower motor, resistor, and relay. Been having blower motors go out every year for a long time, and figure I'll replace the resistor and relay this time to see if it is one of those things that is not doing the job right controlling voltage. Should be about an hour job since I'm used to it.