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Discussion Starter #1
Hi everyone,

My old cats were plugged up so I replaced them with a Magnaflow set (one assembly with all 3 cats).

The Magnaflow cats did not fit very well on the exhaust manifold (their alignment is off a bit).

Now I have exhaust leaks between the manifolds and cat inlets and the CEL is on with P0171 and P0174 (lean on both banks). I'm pretty sure the codes are a result of the exhaust leaks.

The Magnaflow cats didn't come with any gaskets, and there weren't any gaskets between the original cats and manifolds. Should there be?

If not, what is the best way to fix the leaks?
 

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do you have stock manifolds or aftermarket shortys?
 

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No gaskets there. An exhaust shop should be able to adjust it proper. Heating up the pipes with a torch allows them to bend a little.
I second master486, any muffler shop will straigten that out for you cheap or even free. For a $300 plus setup, you'd think it would bolt up fine, right?

Happy Holidays!
 

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Discussion Starter #5
do you have stock manifolds or aftermarket shortys?
Stock.

I second master486, any muffler shop will straigten that out for you cheap or even free. For a $300 plus setup, you'd think it would bolt up fine, right?

Happy Holidays!
I wish they had designed this part with flex tubing. The angles and positions of the 2 front cats have to be perfect fort a leak free fit (but they arent). In addition, the hangers are slightly off.

I'm going to see if I can adjust the hangers and force the thing to fit.
 

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Stock.


I wish they had designed this part with flex tubing. The angles and positions of the 2 front cats have to be perfect fort a leak free fit (but they arent). In addition, the hangers are slightly off.

I'm going to see if I can adjust the hangers and force the thing to fit.
I had mine replaced at a local shop for $200 and they cut the old cats off and welded new ones right in (the two front ones, I just drilled holes with a 2.5 foot long 3/4 inch bit in the third one). The two they welded are actually a little lower and further back than the originals. I'm guessing they probably did that because they had a hard time getting the replacement cats in the same locations from the clearance issues you mentioned.

You know, before I talked to the local exhust shop I was gonna buy that exact same pipe you bought. Good luck with your setup! If I was closer, I'd come help you get it to fit up good! Umm, where are you exactly? I'm on the Gulf of Mexico in Florida!
 

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Discussion Starter #7
I had mine replaced at a local shop for $200 and they cut the old cats off and welded new ones right in (the two front ones, I just drilled holes with a 2.5 foot long 3/4 inch bit in the third one). The two they welded are actually a little lower and further back than the originals. I'm guessing they probably did that because they had a hard time getting the replacement cats in the same locations from the clearance issues you mentioned.

You know, before I talked to the local exhust shop I was gonna buy that exact same pipe you bought. Good luck with your setup! If I was closer, I'd come help you get it to fit up good! Umm, where are you exactly? I'm on the Gulf of Mexico in Florida!
I'm in California -- but I really appreciate the offer to help. Catalytic converters are extremely expensive here because they have to meet stricter emissions specifications.

I just spent 2 hours underneath the car this afternoon trying to get it to fit. The driver side tube is about 1 inch longer than it should be. I concluded that its an impossible job without cutting and welding.

The muffler shop owners around here charge a fortune for their work. Looks like I have no choice.
 

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CA emissions

Yeh, I lived out there for a year and I could never get my car to pass the stricter emissions, I had to keep re-registering the Florida tags. Your other options are other companies that make that pipe with the three converters to pass your emissions. Eastern and Walker I know make them and there is a couple other companies, I just can't remember them.

Sorry I couldn't be more help, I know what a PITA CA emissions are.

Good luck!!!
 

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Discussion Starter #9
I could have easily solved this problem by going to my local junkyard (Pic-n-Pull) and getting a stock set of cats. Unfortunately, in California its illegal for junkyards to sell catalytic converters. :confused:

I really wish Magnaflow would do some better quality control and actually try fitting one of their Y converter assemblies to a real car.
 

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a quality exhaust shop will have "goop" :)

they sell a sealant for exhaust systems that go between the manifold and the cats. my exhaust guy used it any time we had to put the downtubes on, because of the exact angle needed, imperfections in the metal, etc..
 

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Discussion Starter #11
Even 'goop' sealant would not work. The pipe on one side is about 1 inch too long. Also, the angles where the pipes attach to the manifold are different than the stock cats. Magnaflow really fouled up when they made them.

I finally gave up and put my old stock catalytic converters back on. The rear cat was plugged so I cut the rear case open with a hacksaw (took a while), removed all the catalytic material, and then my welded the rear case back together.

The car works fine now, but I'll probably have to replace the rear cat before the next smog test. Or maybe it will pass with just the front 2?
 

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Even 'goop' sealant would not work. The pipe on one side is about 1 inch too long. Also, the angles where the pipes attach to the manifold are different than the stock cats. Magnaflow really fouled up when they made them.

I finally gave up and put my old stock catalytic converters back on. The rear cat was plugged so I cut the rear case open with a hacksaw (took a while), removed all the catalytic material, and then my welded the rear case back together.

The car works fine now, but I'll probably have to replace the rear cat before the next smog test. Or maybe it will pass with just the front 2?
Hey, i'm in CA, and I have only two cats, (3rd/resonator and muffler's deleted). When I smogged, I passed with flying colors with the stock 2 cats at 137,xxx miles. That was this January. My car is also very low to the ground, if you lay down on the ground, you can hardly see my pipes or anything under the car, so I also didn't have to deal with the "VISUAL" inspection of the third pipe. But also my smogger was the local corner gas station place, where I am now good friends with him..
 

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most of the places wont know there was a third cat, especially if they see the first two.

you shouldnt have any problems, unless they go total Kalifornia on ya and complain about aftermarket pipes
 

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Know problem here in PA with the 3rd cat gone :) Passed with flying colors , In fact the guy doing the inspecting tried his best to buy my bird
 

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Discussion Starter #15
Hey, i'm in CA, and I have only two cats, (3rd/resonator and muffler's deleted). When I smogged, I passed with flying colors with the stock 2 cats at 137,xxx miles. That was this January. My car is also very low to the ground, if you lay down on the ground, you can hardly see my pipes or anything under the car, so I also didn't have to deal with the "VISUAL" inspection of the third pipe. But also my smogger was the local corner gas station place, where I am now good friends with him..
Its great to hear that it will probably pass smog without the rear cat.

The case that used to contain the rear cat is still there (but its empty inside). Unless you look close and see the weld seam, you cant tell that anything has been done to it.

Now the question is what to do with the new Magnaflow cat assembly that doesn't fit? I bought it at autopartswarehouse.com and I've read in some reviews that it is a major hassle getting a refund from them (could take months).
 

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Catalytic converters are extremely expensive here because they have to meet stricter emissions specifications.
It's mostly because they have to pay huge fees in order to be allowed to sell them here. For the most part they already meet the standards, just most of them wont pay to sell in CA legally. CARB = failure. Good luck man. I'm probably going to have to replace mine soon also. :(
 

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Discussion Starter #17
Still have a problem

I thought everything was fixed. But now the CEL is on with a P0171 and P0174 (system too lean on both banks).

I have cleaned the MAF sensor and that didn't help.

Before I worked on the cats, I changed the intake manifold because the old plastic one was cracked. I was very careful and used a torque wrench to the recommended tightness, and the rubber o-rings looked like they would make a good seal.

I'll try using propane to look for a vacuum leak.
 

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Brett, I bought the same Magnaflow unit for my 6. I've had no problems. Try contacting Magnaflow customer service. They may be able to help, otherwise, put it up for sale in the Marketplace forum.
 

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I just installed a Catco y-pipe assembly, comparable to the magnaflow unit but cheaper. I'm also having alignment issues, though all the lengths are correct. it seems as tho the problem is minor alignment, but just enough to cause leaks at the flanges. also there seems to be smoke coming from the O2 sensors which i wasn't able to replace yet. maybe a coating of anti seize will stop those leaks until i can replace them? i've got the flanges as tight as they'll go but they're still leaking and white smoke is billowing out from the tail pipes. is this all normal?
 

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I'm in California -- but I really appreciate the offer to help. Catalytic converters are extremely expensive here because they have to meet stricter emissions specifications.

I just spent 2 hours underneath the car this afternoon trying to get it to fit. The driver side tube is about 1 inch longer than it should be. I concluded that its an impossible job without cutting and welding.

The muffler shop owners around here charge a fortune for their work. Looks like I have no choice.
Try San Pedro muffler
 
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