I think my catalitic converter is done

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Xxl2

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I was driving home when i heard abunch of little particals come loss. After that the truck sounded much deeper. The nosie seems to be comming around the cat. I think the honey comb disinagrated. Its a 1991 c 1500 4.3 Is it correct these trucks like a bit of back pressure? Should i even bother with a new cat. If so is one better than the other.?
 

tpass

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if emissions testing/inspection doesn't require it.. I wouldn't bother replacing it.
 

df2x4

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I can tell you this much, I personally wouldn't buy a Magnaflow cat assembly. I've had two of them fail in the same way on my red truck ('97 C1500 4.3L). They break something loose internally and start rattling at part throttle. I've been looking at a Flowmaster replacement but I'm not really sure if they're any better.
 

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1. I'm guessing--but--I bet the '91 still used a pellet-style converter rather than a "honeycomb" "monolithic" style. There's a stainless-steel mesh thats supposed to keep the pellets in their proper place in the converter; but the mesh tears or rusts, and the pellets migrate "downstream" due to exhaust gas flow. We used to smack the muffler of every GM vehicle that went up on the hoist, listening for the Maraca-like rattle of a gazillion little beads bouncing around inside. And it was not at all uncommon for vehicles with pellet-style converters to spit one or two out of the tailpipe as they're fast-idling in the driveway, or at stop signs. Surely they spit them out going down the road...but who would be able to see them?

2. The EGR valve on the TBI engines is a "negative back-pressure sensing" style. Changing the OEM back-pressure affects the EGR valve operation, and therefore engine driveability and emissions compliance. I have the sense that it's not a critical deal; just be aware that back-pressure is deliberately tuned on the TBIs. However, for PERFORMANCE use, "zero" back-pressure is better than "some" (any) back-pressure. If a performance engine runs better with backpressure...it's not tuned properly.

3. When it was me, I put a honeycomb/monolithic style aftermarket converter on my '88 K1500. Nobody likes stinky exhaust, we all need to breathe clean air, they're not that expensive, and they don't kill performance ESPECIALLY at the low-to-medium RPM range typically used by a pickup with shiitty cylinder-head flow like TBI swirl-ports.
 

someotherguy

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I can tell you this much, I personally wouldn't buy a Magnaflow cat assembly. I've had two of them fail in the same way on my red truck ('97 C1500 4.3L). They break something loose internally and start rattling at part throttle. I've been looking at a Flowmaster replacement but I'm not really sure if they're any better.
Dammit I hate to hear that. I've got one of the Magnaflow cats on my SS after one of the OEM units cratered (around 150K miles give or take.) Gotta tell you an LS sounds like absolute trash with one blown out converter and one good.

Richard
 

Xxl2

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When it was me, I put a honeycomb/monolithic style aftermarket converter on my '88 K1500. Nobody likes stinky exhaust, we all need to breathe clean air, they're not that expensive, and they don't kill performance ESPECIALLY at the low-to-medium RPM range typically used by a pickup with shiitty cylinder-head flow like TBI swirl-ports.
Yeah but it be nice for all those hippies to get a taste of they smell. I hate pulling up next to hippies smokeing weed They can inhale some 93 octane
 

HotWheelsBurban

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Yeah but it be nice for all those hippies to get a taste of they smell. I hate pulling up next to hippies smokeing weed They can inhale some 93 octane
Around here it's the wannabe rappers. Can't go anywhere in greater Houston area, with the window down for very long, without smelling weed....fun in the summertime. Especially when you're going to work and don't need to be reeking when you get there.....
 

someotherguy

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Around here it's the wannabe rappers. Can't go anywhere in greater Houston area, with the window down for very long, without smelling weed....fun in the summertime. Especially when you're going to work and don't need to be reeking when you get there.....
Houston's smell is funky weed, for sure.. especially when your work takes you through a lot of parking garages. That crap just lingers. I dunno what they're doing to it these days besides rolling it up in cheap blunts but it smells terrible.

Richard
 
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