ICM soft failure (Page 4/5)
82-T/A [At Work] AUG 04, 07:47 PM

quote
Originally posted by Patrick:

My Formula (different Fiero than the one with the plugged cat) still has it's original pellet style cat. Whether the pellets are still in the cat or not, I don't know... but that engine has always run well, and I don't notice any strong odors from the exhaust.




Do you still have to get it emissions inspected? My assumption is that it started to rust a little inside, which allowed the pellets to go with the exhaust into the muffler. The only issue I perceive is that these pellets would retain heat (though how much heat there would be in the muffler, who knows) and that could make that whole area hotter, longer...

Either way... the replacement honeycomb catalytic converters are a little bit more efficient. They generally flow better, and also heat much more quickly allowing them to do their job faster as well. But it was a decent design. I weighed mine... it was 13 pounds... compared to the Ocelot one which is about 4 pounds.
Patrick AUG 04, 08:17 PM

quote
Originally posted by 82-T/A [At Work]:

Do you still have to get it emissions inspected?



No... so except for a lack of smell (which is good), I have no definitive proof that the cat is actually still doing its job. I had bought an aftermarket cat for my Formula about a dozen years ago, but I put off installing it until it was obvious that the original cat had failed. I'm still waiting!


quote
Originally posted by 82-T/A [At Work]:

Either way... the replacement honeycomb catalytic converters are a little bit more efficient. They generally flow better, and also heat much more quickly allowing them to do their job faster as well.



Interestingly enough, it was the newer style cat that failed (and then plugged up) on my '86 GT.

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armos AUG 05, 12:05 AM

quote
Originally posted by Patrick:

Interestingly enough, it was the newer style cat that failed (and then plugged up) on my '86 GT.

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That's the same mess I found on my 86GT, except it didn't stay in the cat. My muffler was rattling, then it split open. When I took the exhaust apart to replace the muffler I found those little honeycomb bits all through everything, and half the pathway through the cat had converted to free flow.

The old cat was aftermarket, my notes say the date code was from Dec 2000, so it was <10 years old when I got the car in 2010 (already broken up and rattling).
But to be fair - before I found the problem with my ignition, the car did an impressive "Uncle Buck" style backfire on me once. Who knows how many times it happened before. I'm sure that didn't help the cat stay in one piece.

The current aftermarket cat is 12 years old now and no rattling yet, so I guess that's good. I do think it's degraded though, based on my last test before I moved.
Factory cats are probably more durable, if it's lived a happy life maybe it's possible for one of those to still work.

[This message has been edited by armos (edited 08-05-2024).]

Patrick AUG 05, 12:19 AM

quote
Originally posted by armos:

That's the same mess I found on my 86GT, except it didn't stay in the cat. My muffler was rattling, then it split open. When I took the exhaust apart to replace the muffler I found those little honeycomb bits all through everything, and half the pathway through the cat had converted to free flow.



I was fortunate. The outlet end (shown below) of my broken up cat was still intact, which prevented the innards from travelling downstream into my muffler... although when the engine was revved, I could see white "dust" coming out of my exhaust tips.

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82-T/A [At Work] AUG 05, 07:48 AM

quote
Originally posted by Patrick:

Interestingly enough, it was the newer style cat that failed (and then plugged up) on my '86 GT.





Yeah... those factory cats were built to last... just an inferior design I think (in terms of flow)... but well engineered. I hit a coconut on the highway, and it dented my catalytic converter, which actually saved it from hitting my oil pan. But it was like only a couple of weeks after that everything was rattling... just like this.
Dennis LaGrua AUG 05, 09:19 AM
For everyone's sake I will start a new thread where we can list all the imported parts that have worked and lasted.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Dukesterpro AUG 05, 12:41 PM

quote
Originally posted by 82-T/A [At Work]:
Yeah... those factory cats were built to last... just an inferior design I think (in terms of flow)... but well engineered. I hit a coconut on the highway, and it dented my catalytic converter, which actually saved it from hitting my oil pan. But it was like only a couple of weeks after that everything was rattling... just like this.



I hit a coconut on the highway is something I never really thought I'd hear. . . Thats funny as hell for some reason.
82-T/A [At Work] AUG 05, 12:55 PM

quote
Originally posted by Dukesterpro:

I hit a coconut on the highway is something I never really thought I'd hear. . . Thats funny as hell for some reason.




Hah... yeah. It's not as common here in Tampa where I live now, but when I lived in South Florida (basically Fort Lauderdale / Miami area)... you get a lot of that stuff. Especially on the busy back-roads, or I-95.

The crazy thing is that it's not even people harvesting the coconuts... it's just landscaping trucks that have trimmed up a coconut palm tree, and they dump all the **** into the back of a pick-up truck... and then head out on the highway without any nets or anything. So, coconuts sometimes fall off, and... well... haha... not a problem for most cars, but for a Fiero, that'll send you into a spin.


It gets crazier in the outer parts of Ocala / Orlando area. You have large semi-trucks driving around local roads, filled to the top (overflowing) with oranges and grapefruits. When they make fast turns at intersections (keep in mind there are dozens of them every day going through the same routes), they'll usually lose a few dozen oranges that fly off the top and roll all over the intersection. I was going to the World Money Show once (at the Gaylord Palms), and we were at an intersection where a whole bunch fell off. I quickly grabbed one off the ground, and ran back to the car to eat as a snack before the light turned green. Hah...
Jason88Notchie AUG 05, 01:21 PM

quote
Originally posted by Dukesterpro:


I hit a coconut on the highway is something I never really thought I'd hear. . . Thats funny as hell for some reason.




"I caught my car on fire", was kinda out of left field and funny. Glad things are ok there. Wouldn't have been too funny if not.
Dukesterpro AUG 05, 01:49 PM

quote
Originally posted by Jason88Notchie:
"I caught my car on fire", was kinda out of left field and funny. Glad things are ok there. Wouldn't have been too funny if not.



I am assuming you are referring to my 84 idle problem post.


On my defense who could have possibly guessed spraying copious amounts of an incredibly flammable liquid on a blistering hot engine would have resulted in a fireball? rofl

TBH at that point I was so frustrated at that car I would have laughed if it had burned up right there. Lucky for her we got it sorted out lol