Just yesterday my truck begin to lose a small amount of power. My exhaust almost seems quieter, but its making a VERY loud air rush sound. Sounds like an air compressor blowing air. My air tube broke off the cat about year ago too. I tapped the cat with a mallet but i cant hear anything moving around in there so i wasnt sure if it is messed up or not. I can actually hold my hand on the muffler with out getting burned either so i thought that was a little weird that it seems cooler than normal. The cat seems just as hot as always. I also have a cracked exhaust manifold on the passenger side but dont know if that would have anything to do with it. Once its warmed up, whenever i accelerate it sounds like the engine always has a load on it, struggling kind of. Oh and forgot to mention, i replaced the stock converters with one highflow catco last september, so it seems a little fishy that it would go bad so quick. Ive been thinking of maybe cutting the cat off and see how it runs and if it still makes that air rush sound. Id like to see if the truck is throwing any codes, but i thought those can only be read when the check engine light is on. Anyone got any ideas? Its very frustrating since i cant pinpoint whats wrong

 

well what year is it, if it is an efi then i would first check the fuel pressure, then if that is within spec. do a cat test.

 

Its a '91 302...

 

An engine can throw codes without the CEL coming on. Check it, go to http://www.fordfuelinjection.com for instruction's and a code list. Good luck, sounds kinda like a cat problem..but..if its a brand new one then....

You should have replaced the cat with one that doesn't require the air pump.

 

Reason i replaced it with the cat i did is because it was dual inlet, and the dual inlet has the air tube hookup. I guess next time around i will have it y-ed into a single inlet cat w/o air, unless i put true duals on it. But, will the cats that have no air hook-ups still do the same job as one with the air hooked up? Thanks for the info.
EDIT: Reason being for the air hook up is because i have emissions testing in my area and dont want it to fail the sniffer.

 

The catalytic converters designed without an air tube are designed so that they can perform as well as the "standard" cat, but without the air tube. I believe the process is slightly different, and more area for catalytic functions to take place as well. I don't believe that you will fail emissions, though you'd have to contact a manufacturer on that part. I don't have enazi's here so ^_^.

 

Well i checked out the cat today and the insides were mostly broken up and a lot of it had melted. So my problem was a clogged cat...

 

A clogged converter does not happen by itself, theoretically a catalytic converter should last forever since there are no moving parts, converters are made from stainless steel and coated ceramic and the washcoat and PGM (Platinum Group Metal) or precious metal that coats the ceramic will not degrade if the correct exhaust gases are present. So, you must have somehting else wrong that casued the converter failure. Fix that problem before replacing the converter. A melted converter is usually from raw fuel ingnited in the exhaust stream like a possible misfire or extremely rich exhaust. Aftermarket converters carry a 50,000 mile warranty on the metal shell and a 25,000 mile warranty on the catalyst inside (Eastern Catalytic carries a 50K warranty on the catalysts and the shell) But the warranty is only good if the converter fails because of a converter defect not an engine problem that damaged the converter.

Good Luck!

 

About 5 yrs ago when I was 16 I ran a full tank of mixed gas (oil/gas) and it clogged my converter up, I had to take it off and punch all of the honey comb crap out.

 

Oh yea thats also illegal.

 

why did you mix the fuel up, are you running a 2 smoke or something

 

No, I was late for work and had no money for gas so I got 2 10 gallon gas cans from our shed and filled her up. I was desperate

 

I think your CAT melted the core because of the air leaking into the cracked exh. manifold, throwing off the O2 sensor and air/gas mix. If it is the cast iron type I would replace with shorty headers, JBA is what I use. ~ Ron