broken cat question

stevstum · 05-16-2001, 11:19 AM

My front cat on the left side broke inside and was making a rattling sound. It stopped and I did not think about it anymore. Know it is letting just enough air though that in normal driving there seems to no problem. If I hit the gas even a little hard I here a weird sound that I can not discribe from the that side of the engine. I thinking that has to do with the blocked cat. My question is will this hurt the engine. I was thinking of getting an of road h-pipe, but I have to convince the wife that it is a needed fix.

------------------
Steve Stumbaugh

89 LX 5.0 5sp.
Removed air silencer
Motorcraft 8mm wires
Autolite platinum plugs

blueneonman1 · 05-16-2001, 12:26 PM

The catalytic element is a rock-hard piece of who-knows-what with a bunch of little tiny holes in it. If pieces of the element become dislodged and the holes dont flow air anymore, depending on how big of a piece, I would think it would give too much backpressure. I cleaned out my cats awhile ago and now I am hearing this sound from like my muffler area. It sounds like things are rolling around in the exhaust when I brake. I'm wondering if I missed some element when I cleaned it, or it could be totally unrelated. Does yours sound like that? An offroad h-pipe would be a good addition anyway

red82gt · 05-16-2001, 01:14 PM

When the catalyst in my catalytic converter broke up it was blocking my exhaust, I pulled the whole exhaust system off and shook four pieces of a half melted honeycomb out of my muffler. When I was climbing a hill I could literally feel when the pieces dislodged and went into the muffler. I'd say it sounds like you've got a legitimate case for removing a stock convertor. Do you have smog testing there?

------------------
GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B+M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

stevstum · 05-16-2001, 03:42 PM

I heard it in both right side cats. Like I said it just stopped until a few weeks ago. With having to much back pressure, will that blow any seals or damage anything?

red82gt · 05-16-2001, 07:23 PM

It'll make that bank run rich, foul your plugs, drop your fuel economy, in short, I'd do something about it immediately.

05-16-2001, 11:19 AM	#1
stevstum Registered Member Join Date: Mar 2000 Location: Salem, Or. USA Posts: 233	broken cat question My front cat on the left side broke inside and was making a rattling sound. It stopped and I did not think about it anymore. Know it is letting just enough air though that in normal driving there seems to no problem. If I hit the gas even a little hard I here a weird sound that I can not discribe from the that side of the engine. I thinking that has to do with the blocked cat. My question is will this hurt the engine. I was thinking of getting an of road h-pipe, but I have to convince the wife that it is a needed fix. ------------------ Steve Stumbaugh 89 LX 5.0 5sp. Removed air silencer Motorcraft 8mm wires Autolite platinum plugs

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05-16-2001, 12:26 PM	#2
blueneonman1 Registered Member Join Date: Mar 2001 Location: Palm Harbor, FL Posts: 208	The catalytic element is a rock-hard piece of who-knows-what with a bunch of little tiny holes in it. If pieces of the element become dislodged and the holes dont flow air anymore, depending on how big of a piece, I would think it would give too much backpressure. I cleaned out my cats awhile ago and now I am hearing this sound from like my muffler area. It sounds like things are rolling around in the exhaust when I brake. I'm wondering if I missed some element when I cleaned it, or it could be totally unrelated. Does yours sound like that? An offroad h-pipe would be a good addition anyway ------------------ Blueneonman - '95 5.0L Mustang GT Convertible \| K&N Custom Cold Air Intake \| FMS 9mm Wires \| Hollow Cats \| Flowmaster 2 Chambers \| BBK Subframes \| 6-pt Rollcage \| 14deg Timing \| King Cobra Clutch \| FMS Adjustable Clutch Cable \| Coolest Neon Lighting on a Mustang EVER! Homepage: http://www16.brinkster.com/blueneonman/ Best time: 14.578 @96.20mph

05-16-2001, 01:14 PM	#3
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	When the catalyst in my catalytic converter broke up it was blocking my exhaust, I pulled the whole exhaust system off and shook four pieces of a half melted honeycomb out of my muffler. When I was climbing a hill I could literally feel when the pieces dislodged and went into the muffler. I'd say it sounds like you've got a legitimate case for removing a stock convertor. Do you have smog testing there? ------------------ GT-40 heads (ported, polished, + milled), B303 cam, 1.7rr's, JE pistons, Offy intake, Carter AFB 625cfm carb, Flowtech 1 5/8" shortys, Flowtech X-pipe, MAC Flowpath exhaust, MAC pulleys, 373's, subframes, Eibachs+Tokicos, B+M ripper, FMS Clutch, Zoom Quadrant+cable, 17" CSA Ultra rims, 235/45ZR17 Yokohama AVS S4's, MSD 6A ignition+coil, FMS 9mm wires, Carbed, Naturally Aspirated, and Nasty!

05-16-2001, 03:42 PM	#4
stevstum Registered Member Join Date: Mar 2000 Location: Salem, Or. USA Posts: 233	I heard it in both right side cats. Like I said it just stopped until a few weeks ago. With having to much back pressure, will that blow any seals or damage anything?

05-16-2001, 07:23 PM	#5
red82gt Sober voice of Reason Join Date: Nov 1998 Location: Kelowna, B.C., Canada Posts: 1,514	It'll make that bank run rich, foul your plugs, drop your fuel economy, in short, I'd do something about it immediately.