My sons 97 with the 5.4 L. has about 230k miles. Truck runs great. I was trying to find what sounds like an exhust leak. I've narrowed it to the 2nd cat. on the passenger side. Don't feel any exhust blowing, but it sounds like a leak.
Can the cat just burn out on the inside and make that sound? Any suggestions? I just called a scrap yard and they told me its illegal to sell them.
Can we remove them and still hook up the O2 sensors? Does someone make replacement cats or even a pipe to replace them with??
thanks, bullseye670.................

 

Hi; Removing the catalytic converter will cause you to fail an emissions test. you will need to drill new holes for the Oxygen sensor, Pre and post. Post sensor will see increased CO and HC and will cause a MIL lamp. (Sensor will read well over .5 Volt, which is a rich signal) The PCM will see this well over .5 Volt, and try to compensate. The truck will run lean. Here is a new converter;

http://replacement.autopartswarehous...verter&dp=true

-Jimmy

 

You can hang a couple O2 sensor eliminators in place of the rear sensors. They trick the computer into thinking everything's OK. The front two will be left alone. You will get a light if you don't. The front two sensors are pre-cat, so their readings would not be affected. The rears just measure the effectiveness of the emissions system, they don't affect the engine. The only problem you would encounter is a CEL. It won't run lean or anything funky like that.

As was said, you will fail both visual and sniffer emissions tests.

If you know somebody who can inspect it for you, and pass it regardless, go for it. Sounds better that way too, IMO.

If you want to do it right, rip that y-pipe off, have an exhaust shop build you a new one with only 2 high-flow cats. You will only have 2 cats instead of 4, but it will not throw a light. It will flow better and you will gain a couple more hp and a different exhaust note.

 

Not really, Triton. The rear o2 sensors measure the efficency of the catalytic converter, and if there is no converter and the sensor is re-installed, the short term fuel trim will be in excess of 39%. Long term won't be far behind. When measured on a lab scope, The rear sensor should stay almost flatlined. If the sensor has a waveform, then the converter has failed, Period. Without a converter, the PCM will see the same thing, a highly active sensor. The computer WILL compensate for the now active post 02, sending fuel trim lean. But why go to all that trouble? For 5 horsepower and a differnent exhaust note? I'd put on the converter with a Thrush or a Flowmaster 50 series, and it'll sound pretty good WITH the converter.

-Jimmy

 

I think you need to take a look at the exhaust manifold studs before the converters themselves. Yes, I know you're hearing the downstream cat, but check the studs anyways. Especially with 230K miles, you've probably got one or more broken exhaust manifold studs just adding to whatever noise you're already hearing.

If you really need a converter, they come pretty cheap from most any exhaust chain.

 

Thanks for the input guys. don't have to worry about any emissons tests. We don't currently do them in michigan nd I live in the country so even if they come back they only seem to do the larger cities.
If I was to replace the converter can a replacement be welded in?
The whole thing is this is my sons firtst vehicle. Heck, he's only got a permit right now. Won't have his drivers L. for a few months. I got a real clean 97 with all the miles for $2,000. It was a company truck and had all the maintenence kept up. Except the cats I guess. Even got all new c.o.p.'s.
Anyhow, my son wants to put on a flowmaster. Yea, I know, it would sound even better if we remove the cats. I,m just wondering if I can get them replaced. If my memory serves me correct, a shop can't remove them, by law.

 

They can be replaced if the vehicle has over 50,000 miles I believe. As far as just removing them, most exhaust shops won't because that is illegal.