Need real advice on Cat removal

[firedawg2008]

Have a 2003 XLT with the 5.4. Power is down, sometimes when stressed uphill or light towing the service engine light flashes and it goes into a kinda "limp mode" during that time the A/C turns off and it won't accelerate, lasts about 30 seconds light stops flashing then it accelerates again. Mechanic changed the plugs and packs, said everything else looked good, though he couldn't find the fuel filter anywhere, but he did get some low readings from the cats so he believes they are clogged. Being a 03 with 240K, and I don't really have the money I don't really want to buy new ones. So if I remove them or punch them out what am I looking at, anyone have real world experience removing them? I'm sure it'll trip the service engine lights but will it still run normally especially since the 02 sensors will be useless? I am in South Carolina, no inspections so no issues there. If this is an option whats better punch them out or replace with pipe? He did bang them a little to loosen them up and I bought some Cataclean I am going to run thru and see if that works with some high test, just looking at my options. Thanks all

 

[stamp11127]

What readings were low at the cat? Usually if they are not efficient it will throw a code or run hot if plugged.

 

[firedawg2008]

he said something about 2.5 at the cat, he said he had to pull the 01 sensors so I assume thats where he checked it.

 

[Hamfisted]

Your "mechanic" couldn't find the fuel filter on the Expy? Or couldn't find one at the auto parts store ? Either way, find a new mechanic.
It's up under the left rear passenger seat area of the chassis, right up against the fuel tank behind a plastic cover that pops off. Push the blue line lock tabs in to release the lines. Did anybody do a fuel pressure test at the fuel rail ? If it's the original fuel pump in the Expy it's probably on it's way out as well. But like Stamp said, bad cats usually throw a code.

https://www.amazon.com/Motorcraft-F...rcraft+FG1063&qid=1564402341&s=gateway&sr=8-1

 

[firedawg2008]

he actually found it today and will be changing the filter, he said it was behind a "trap door" lol. So he's changing it today and I am going to run the cat cleaner on the way home, I already bought it, may as well use it, I don't remember him mentioning a code for the cats but I'll ask again. Worse comes to worse any recommendations on removing the cats or punching them out, have you actually done it or seen it done on a expy or f150? Thanks guys for the input

 

[johnboneske]

he actually found it today and will be changing the filter, he said it was behind a "trap door" lol. So he's changing it today and I am going to run the cat cleaner on the way home, I already bought it, may as well use it, I don't remember him mentioning a code for the cats but I'll ask again. Worse comes to worse any recommendations on removing the cats or punching them out, have you actually done it or seen it done on a expy or f150? Thanks guys for the input

There is no code for the cats... they will produce codes that show for something else, but nothing directly for them. As I remember, Cats dont have much if any back pressure, so if your "mechanic" finds back pressure, they are bad. There are 2 cats on each side for your Expedition too. I have never been able to find a shop that will cut them out and weld in a straight pipe...

 

[stamp11127]

You have 240K on the clock, how much power do you expect from the engine? I can bet you have at least normal wear on the engine, possibly more if not maintained correctly.

I don't think there is any member on here that would guide you along the path you seem to be headed down. Most of us on here enjoy breathing the cleaner air than we had growing up. Get away from any city far enough and you can still the haze from various emissions even with the current emission equipment on cars.

But here is a link on the pro's and cons of removing them:
https://greengarageblog.org/13-removing-catalytic-converter-pros-and-cons

 

[TomB985]

You have 240K on the clock, how much power do you expect from the engine? I can bet you have at least normal wear on the engine, possibly more if not maintained correctly.

Perhaps all of it or close to it? If the engine is running correctly he should be making equal or close to the rated power. Some engines even do better as they loosen up; this is the first thing that came up on Google: A 243,000 mile Porsche making more power then some with new engines were getting.

https://jalopnik.com/i-dyno-tested-my-1999-porsche-911-with-243-000-miles-1788130306

I don’t advocate removing cats, though, It’s irresponsible at very best. The quick way to tell if the cats are clogged is to remove the upstream oxygen sensors and see how it runs. If they are clogged, it should run much better as the excess pressure vents out the oxygen sensor port before the cat. If it runs similarly, the problem is elsewhere.

 

[TomB985]

There is no code for the cats... they will produce codes that show for something else, but nothing directly for them.

https://www.obd-codes.com/p0420

 

[johnboneske]

https://www.obd-codes.com/p0420

but that's a O2 sensor code. I have had that code before and it wasn't the CAT. There isn't any true code for a CAT. The only way to tell if a CAT isn't working properly or clogged is to remove the front O2 sensor and see what kinda pressure you get out of the hole... If you get a decent amount of air its clogged, as CATS don't have any back pressure associated with them.

 

[Plati]

I thought you could use an infrared non-contact temperature "gun" to measure the temperatures of the cats. They are a small chemical plant and if working right the temperatures will show that?

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

 

[TomB985]

but that's a O2 sensor code. I have had that code before and it wasn't the CAT. There isn't any true code for a CAT. The only way to tell if a CAT isn't working properly or clogged is to remove the front O2 sensor and see what kinda pressure you get out of the hole... If you get a decent amount of air its clogged, as CATS don't have any back pressure associated with them.

So a sensor designed to monitor the converter can’t generate a code to indicate that it’s bad? The definition of that code is “converter efficiency below threshold”. Which may or may not have anything to do with it being clogged. A converter can fail without clogging.

But yes, to check for a clogged converter you remove the upstream sensor. Very curious to hear from the OP on the results.

 

[Ulver]

So a sensor designed to monitor the converter can’t generate a code to indicate that it’s bad? The definition of that code is “converter efficiency below threshold”. Which may or may not have anything to do with it being clogged. A converter can fail without clogging.

But yes, to check for a clogged converter you remove the upstream sensor. Very curious to hear from the OP on the results.

Another way of testing the o2 sensors is using a scanner that provides you with live data. Bring up both s1 and s2 o2 readings, and look at the pattern. If the s2 frequency is following the same pattern as s1, that is showing that the oxygen isn't being converted into the proper gases. If you get a flat line for s2, that's usually a good sign that your catalytic converter is working properly.

Bad:
Bank 1 sensor 1
/\/\/\/\/\/\/\/\
Bank 2 Sensor 2
/\/\/\/\/\/\/\/\

Good:
Bank 1 Sensor 1
/\/\/\/\/\/\/\/\
Bank 1 Sensor 2
____________ <---- Flat line, gas is being converted properly.

 

[Frank Swygert]

If the O2 sensors have never been changed, change them! Those alone can cause power and economy to go down. They should be changed after 100K miles whether they throw a code or not.

 

[firedawg2008]

ok to close this out, plugs, coils packs and fuel filter changed, ran 2 batches of catalytic converter cleaner thru and it got slightly better. Cats were $440 plus install so I paid $200 to have them removed, holy crap what a difference, its a little louder but not obnoxious, has a nice gurgle but power is better then its ever been. Check engine light is on but I don't care it has 237K on it so nobody's gonna care when I tell them why its on whenever I sell it. Thanks all for the inputs