Bad catalytic converter

[wallyuwl]

Long story short, I have a p0420 CEL code, apparently a bad catlytic converter (vehicle is a 2003 Pontiac Vibe about 120k miles).

I found a direct fit converter from Rock Auto for under $300 and one for probably about the same price at Advance (depending on what coupon code I can find). From what I've found on the internet direct fit cats are pretty easy to install. Repair shops want $600+, and those might even be for universal fit, I'm not sure they didn't say. So I'd like to do it myself if it is pretty easy with a direct fit.

My main question is: Anyone know if it easy to do on a Vibe (same as a Corolla or Matrix)? My biggest worry is getting all the bolts apart. I don't have a torch and always fear breaking something.

Also, my other main worry is if I need to replace any bolts (if the originals break or something during the uninstall process). Anyone know what size and quantity bolts, washers, etc. I should buy ahead of time to have on hand?

Thanks.

 

[Mr Nice]

The aftermarket Cat should come will the necessary bolts/washer/spring, etc.

Spray some penetrating oil on the bolts and it should be very easy to remove. I did the same thing you will be doing on a Honda with 120K miles and I had zero problems.

 

[oggb]

Not 100% certain but could it not also be an O2 sensor?

Have you tried clearing the code to see if it persists?

 

[EricF]

Pre-soak the nuts & bolts with penetrating lube, PB Blaster's my favorite.
let it soak for a couple hours & hit it again.

I really doubt you'll have any problems removing the bolts at all.
the car's new enough, unless they're heavily rusted, I wouldn't be to concerned with it.
Just make sure you get the o2 sensors out in 1 piece.
AND make sure you have new exhaust gaskets.

hardest part of this job is getting altitude on the car. a pair of jackstands should give plenty of room..

but your friend will be PB Blaster!

 

[wallyuwl]

Thanks guys. I have some PB Blaster and will use that. I have a pair of ramps, and a pair of jack stands to get the car off the ground fully.

Glad to know replacement bolts and such should come with the kit. Below is what I'm looking to get (when they get it in stock - I'm not in a hurry with a cat):

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_49-State-(excluding-California)-Direct-Fit-Catalytic-Converter-Bosal_20201821-P_145_R%7CGRPEXHAAMS_1107630931____

Besides the above they have a Walker direct fit, but you need to purchase the resonator separately (about the same cost together as the above - I'd rather get it as one package, also more likely probably to have all the bolts and springs and such included if it is one package).

This is the page with all the exhaust related products:

http://shop.advanceautoparts.com/webapp/...151_10051_-1___

I'm still unsure what I'd need for gaskets?

 

[Trav]

PO420 doesn't automatically mean a bad cat.
At 120K would try new O2 sensors first and look for any leaks before the cat.
Even if it doesn't fix the problem its not not money out the window as new O2 sensors are a good idea at this mileage with a new cat anyway.

Use Denso OEM fit O2's and not anything universal,Rock usually has them at good prices.

 

[wallyuwl]

Well, turns out noone has available the catalytic converter I was looking at. Rock Auto says it is unavailable, too, and just in the last hour or so took it off their web site.

Now I'm looking at this one:

http://www.autopartswarehouse.com/sku/Pontiac/Vibe/Eastern/Catalytic_Converter/2003/Base/4_Cyl_1-dot-8L/EAST40407.html?tlc=Engine+%26+Drivetrain&intcmpid=Product+Listings+Best+Seller

I'm not totally sure what accessory parts all come with it. Maybe I'll email the manufacturer.


The CEL has given this code twice now after being cleared. I've checked the online documentation associated with my scanner, and GenVibe, and am 99% sure the only way to fix this CEL is to replace the cat. Some on GV have tried just replacing the downstream O2 sensor, and even trying to bypass the cat, to no avail.

 

[MarkM66]

Does the car run any different?

 

[wander2039]

My Aspire has basically the same code. It can be sluggish at times ,mostly before it warms up, but for the most part runs great. No odd smells like a few cars I've been around I was thinking about trying the sparkplug defouler trick first. Cat's are cheap for the Aspire though compared to your Vibe. On the Vibe I wonder how tricky it'll be since it's right behind the engine and attached directly to the exhaust manifold, my parents have one. I wouldn't think a universal would work.

 

[Vikas]

It is given that after market converter will last about 6 months or less. There are zillions of posts on P0420. Please do some research before purchasing an after market converter.

- Vikas

 

[JTK]

I've always wondered if just letting that downstream O2 sensor read ambient air would prevent catalyst inefficiency codes. Basically leave a dummy O2 sensor and wire in place in the stock downstream location and have the 'real' plugged-in sensor hard mounted somewhere out of the way in a safe location.

I suppose if the software is advanced enough that it needs to see a change from the downstreamer, this wouldn't work. I know the system needs to see a change from the upstream sensors. Dunno about the downstream.

I'll tell ya, this issue is going to cause a lot more vehicles to go to the scrap-heap. The cost of an integrated Y-pipe, dual cat system will easily exceed the value of a well used car.

Joel

 

[wallyuwl]

No, it doesn't drive any different. Gas mileage is the same as best I know (wife drives the car mostly). It doesn't rattle or anything at this point. So I'm not too worried about it at this point. I'll probably start with the downstream O2 sensor even though I know it is unlikely to fix the problem (at 120k miles O2 sensors are due for replacing probably anyway), clear the code, and if it comes back do the work in summer. I don't know a lot about cat mfgrs, but Eastern seems pretty reputable. The warranty is 5y/50k, and we won't have this vehicle five more years, though we'll probably be at 50k in three years. But that is probably about the point we'll be getting rid of the car. About seven years ago my then girlfeiend, now wife, and I had two separate cars that each needed a new cat within a couple months of each other. They lasted several years until we got rid of both cars. They were universal ones welded in at a muffler shop.

 

[Vikas]

Erase the code and see if it comes back regularly. You can first try chemical approach. CRC GTP and Cataclean are two such chemicals. There is another much drastic chemical approach proven to work by a very reputable on-line mechanic but personally I would not use it, so I will not list it here.

Otherwise, the O2 extender (anti-fouler) works in all the cases but it is somewhat cheating.

- Vikas

 

[ponderosaTX]

I would reset the code and run a fuel system cleaner (like Techron Concentrate, Gumout Regane) though the gas tank to make sure that the code recurs. If the code does recur, you can try the spark-plug anti-fouler trick described here:

http://forum.mpvclub.com/viewtopic.php?t=22162.

All of the postings on this trick that I have seen report that it works. Post-2000 Mazda MPVs are equipped with four cats (two for each cylinder bank) and the O2 sensors only monitor the status of the two "pre-cats" installed in the exhaust manifold. When a pre-cat no longer passes the OBD-II cycle test, the main cat farther downstream in the exhaust pipe may still be working. Since the pre-cats heat up more quickly than the main cats, their primary function is to reduce emissions during warm-up before the main cats reach operating temperature.

The anti-fouler trick fools the OBD-II computer into believing the failing pre-cat is still working.

 

[dailydriver]

Originally Posted By: Vikas
Erase the code and see if it comes back regularly. You can first try chemical approach. CRC GTP and Cataclean are two such chemicals.


The Cataclean (two treatments, no less) did NOT work for me.

I'm guessing that my cats are blown out (or burned out), since my car has much more of a 'bark' on that first startup 'catch' then it did before, and the 420/430 codes come back within the same driving cycle, sometimes less than ten minutes from the last code erasure.

Hopefully, Eastern, Catco, or Magnaflow cats will last longer than the six months you claim. Especially with all new; O2s, plugs, wires, MAF cleaning, etc.

Otherwise, it looks like new, blueprinted injector time. OUCH!!

 

[Vikas]

CRC chemicals makes Guaranteed To Pass. Generally CRC stuff is highly respected. You could try that.

If you can get your hands on a decent scanner, look at Mode $06 data. Catalytic converter results will tell you how badly you are blowing that test. If it is just on borderline, you might be able to fix it with chemical approach.

The trouble is manufacturers (at least Honda/Toyota/Nissan) set the cat converter test very stringently. The light goes on when the efficiency drops from 100% to 95%. You could still pass the sniffer test with flying colors but unfortunately when the check engine light is ON, that is the end of the game.

After market converters do not have sufficient catalyst material and invariably you will get the code back. There are lots and lots of documented cases on internet where guys have gone through multiple after market converters.

- Vikas

 

[dailydriver]

If that happened to me, after replacing all of the above, due to overly sensitive, 49 state, ECM catcon test parameters, I would just go to a tuner and have them edit-out the light with EFI Live, or such.

I know people who have gone through the state inspection's OBD 2 plug in readiness tests after having done this, with; long tube headers, NO catcons OR rear O2s, and passed.

How they got past the 'visual' part, I have NO idea.