The catalytic converter job from hell

[yosh18981898]

Well, my X has been running like crap. After driving home from school on wed. night I noticed that when I revved the engine, the exhaust system would make kind of a plugged popping noise that increased in frequency as the RPMs climbed. I figured that my factory cat had finallly bit the dust.

The next day, I went to parts store and found that they wanted $200.00 for a factory replacement cat, OR I could get the universal 2.25" in/out cat for $42.99 and make it fit myself. Always being one to try a project, and a poor college student, I went for the universal one.

When I got home it took me about 4 hours with a sawzal to get the old cat off. Then I welded a piece of pipe to each end of the new cat, made a flange to bolt onto my y-pipe and welded that to "in" pipe on the cat. It looked like this

I had to buy a blank gasket sheet to make a flange gasket because no one sold them.

After 8 hours of work, I was finished. Now it just has a slight exhaust leak at the flange, but you can only hear it when you get on the gas. The only problem is that it helped, but didn't fix the running like crap problem

 

[MrShorty]

Cats don't normally go bad unless something makes them go bad (usually excessive unburned fuel from running too rich or misfiring cylinders). Any chance that "popping noise" from the exhaust (that varies with engine RPM) is a misfiring cylinder? First thing I would probably do is a cylinder balance test.

 

[yosh18981898]

Yeah, I've got no doubt that there is something else wrong with the engine, but nothing that I can figure out. It's got a definate miss to it. It's going in to the mechanic when I get back for Christmas break.

Like I said in my 911 post, I've replaced or checked the:

Spark plugs
ignition coil
spark plug wires
fuel filter
air filter

and put seafoam through it.

 

[410Fortune]

Actually I have had the catalysit inside the cat dcome loose from being abused off road, this clogged up the exhaust and the truck ran like crap.

Excessive fuel is what kills the exhaust. Ford engines run rich when you do intake and exhaust mods without tuning the computer to lean it out a bit.

So if you are running rich you can expect to get about 2 years out of a aftermarket cat.

My cat is now hollow because I replaced it 3 times, I dont have an 02 after the cat and CO does the sniffer and visual on my truck based on running the speed density 2.9L in there, so the OHV 4.0L burns about twice as clean.....

The power I gained from having a hollow cat is NICE.

 

[yosh18981898]

I'll just be happy when it runs right.

BTW, I have a KKM filter on there, maybe this is making run rich?

In IL, we don't have any kind of vehicle inspections at all. So I could get away with a straight pipe. Too bad my parents said no Which I don't really understand seeing as how the vehicle and everything having to do with the vehicle is funded by me. They basically said that if I put a straight pipe on it, I couldn't do it in their garage nor could I ever park in their driveway without a catalytic converter.

They didn't say this because they are concerned about the enviorment, but because it would still be breaking the law, even though there is no way that I could get caught. In a sense I kind of agree with them, its funny how the values that were taught at a young age will stick with you for the rest of your life.

 

[410Fortune]

the KKM might not be helping, also the crap they put in our gas doesnt help the catalyist.

You could have just knocked the catalyst out of the cat and bolted it back up
Anyways you got it replaced now, so good job

Your parents are wise for instilling those values on you.

 

[spindlecone]

Yosh
I feel your pain as to removing the cat, when I installed a banks system on my R.V even tho the cat was clamped on it would not budge (sees alot of heat and sticks like epoxy to the pipe) Next time if you have a compressor and an air hammer you can get a sharp T shapped chisel bit, cuts off the cat like butter, good luck with the other problems

 

[EBInterceptor]

Just out of curiousity, how does the cat work? I've never really thought about it, other than I don't want a $1000 fine for not having one.

 

[00XLS]

Just out of curiousity, how does the cat work? I've never really thought about it, other than I don't want a $1000 fine for not having one.

From what I understand theres well... a cataylist inside of it and when you run the "nasty" exhaust gases over/thru it, out the other end come "good" exhaust gases, mainly just co2 and not NOx's, and whole bunch of other crap.

 

[MrShorty]

There's an article on catalytic converters at www.howstuffworks.com