Exhaust Problem

1.8-liter VVTL-i (2ZZ-GE) and VVT-i (1ZZ-FE) engine, transmission, exhaust, intake, and performance tuning discussions
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romeroom
Posts: 28
Joined: Wed May 16, 2012 6:57 pm

Exhaust Problem

Post by romeroom »

This involves a 2003 Vibe AWD with 150k miles.

I was told by a mechanic a back pressure test was off the charts, making the catalytic converter a likely culprit. Since I had to drive 350 miles to get the car, I drilled a couple holes ahead of the cat near the second 02 sensor--per the mechanic's recommendation--to let off the pressure.. I got home and cut off the old cat thinking I could install a universal cat, given the $400+ cost of an OEM. After not being able to adequately fit a universal (and now I can't return it), I took off the piece just below the exhaust manifold, and to my surprise I find another "honeycomb" looking things which is called an Exhaust Manifold Catalytic Converter. (http://parts.nalleygmc.com/products/Pon ... 71578.html" onclick="window.open(this.href);return false;) Gee, I wonder if that's the one that's plugged. The cost of that one alone? Another $400+ dollars.

I'm going to make a home made back pressure gauge to see if there is any back pressure now that almost everything is off the exhaust.

Any suggestions? Do we really need to have two catalytic converters in a car?
2003 AWD Vibe, 153K miles.
romeroom
Posts: 28
Joined: Wed May 16, 2012 6:57 pm

Re: Exhaust Problem

Post by romeroom »

I've confirmed the exhaust manifold cat converter is plugged.

I will entertain suggestions other than spending $400 on a piece of hardware not much bigger than the size of my forearm.
2003 AWD Vibe, 153K miles.
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joatmon
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Joined: Fri Mar 21, 2003 5:19 am
Location: SMC MD

Re: Exhaust Problem

Post by joatmon »

The purpose of an automobile catalytic converter is to reduce exhaust/pollution. I guess in our cars two are needed to get the exhaust down to the desired level.

Some people with AWDs have gutted that first cat in order to achieve a small performance gain. I think they have been able to run that way indefinitely with no damaging side effects. I guess it depends on where you live an what sort of emissions testing the car has to go through.
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romeroom
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Joined: Wed May 16, 2012 6:57 pm

Re: Exhaust Problem

Post by romeroom »

joatmon wrote:The purpose of an automobile catalytic converter is to reduce exhaust/pollution. I guess in our cars two are needed to get the exhaust down to the desired level.

Some people with AWDs have gutted that first cat in order to achieve a small performance gain. I think they have been able to run that way indefinitely with no damaging side effects. I guess it depends on where you live an what sort of emissions testing the car has to go through.
I too appreciate the purpose of the cat and fully intend to replace a bad one. At this point I just need to run the car for a bit until I can get the money to replace it. Incidently, I find it disconcerting that an entire exhaust system for this car could cost well in excess of $1000 in parts alone.

As it relates to gutting out that first cat, would I need to remove the entire exhaust manifold (which is connected to it), or can I do it from underneath the car, just chipping at it? Thanks for your input.
2003 AWD Vibe, 153K miles.
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joatmon
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Joined: Fri Mar 21, 2003 5:19 am
Location: SMC MD

Re: Exhaust Problem

Post by joatmon »

romeroom wrote:
As it relates to gutting out that first cat, would I need to remove the entire exhaust manifold (which is connected to it), or can I do it from underneath the car, just chipping at it? Thanks for your input.
I've never touched an AWD, and the exhaust in my base is different, so I don't know. However, if I were to do that, then I'd take it off the car first. Apparently these engines are supposed to inco9rporate exhaust gas recirculation by having a little overlap between the intake and exhaust valve timing, to allow the intake to suck in some air from the exhaust, If that's true, then it would be better to make sure all the debris is away from the engine. Also a good idea to do the process where it would be easier to avoid inhaling converter guts

I thought I remembered someone selling a pre-gutted one, but only found where stickyrpice was looking to replace his gutted one several months back viewtopic.php?f=46&t=38490" onclick="window.open(this.href);return false;

someone on here has gutted one, hopefully they are still around and can offer advice.
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romeroom
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Joined: Wed May 16, 2012 6:57 pm

Re: Exhaust Problem--SOLVED

Post by romeroom »

I was able to easily gut out cat converter attached to the exhaust manifold while it was still attached to the vehicle. For anyone considering it, the "guts" are not securely welded or attached to the sides of the cat. It seems to snap it to ridges on the inside of the cat housing, along with the fiber glass material. In other words, once you break the honey comb material from the bottom the rest practically falls out. I used compressed air through the O2 sensor hole, though very little came out.

The honey comb material was nearly 75% clogged. After putting the exhaust back, the car was back to normal. Normal back pressure. No CEL. Easy smooth acceleration from 0 - 80.

Thanks for the support, everyone.
2003 AWD Vibe, 153K miles.
wmdiess
Posts: 35
Joined: Thu Mar 24, 2016 12:13 pm

Re: Exhaust Problem

Post by wmdiess »

I realize this is a stale thread, but I'm sharing it in case someone else has the same problem.

This thread solved the problem on my 2003 AWD Vibe. The car had lost all power and I was stranded about 250 miles from home. A 17mm socket was all it took to disconnect the pipe. I was surprised because exhaust bolts usually break off. A screwdriver and hammer allowed me to break out all the clogged media, only took an hour.

Hooked it back up and the car purred like a kitten. The car is in really good shape, so I will invest the $$$ for a new manifold, but this got me home and proved that the manifold CC was the problem.

Bill
Caretaker

Re: Exhaust Problem

Post by Caretaker »

stale??? I thank you for not needlessly starting another thread. Wish others would do the same. Good job and thanks for taking the time to help others. That never gets stale.
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