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How to check a cat converter ?? by notaguru
Started on: 04-30-2014 05:22 PM
Replies: 18 (387 views)
Last post by: sardonyx247 on 05-03-2014 04:24 AM
notaguru
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Report this Post04-30-2014 05:22 PM Click Here to See the Profile for notaguruClick Here to visit notaguru's HomePageClick Here to Email notaguruSend a Private Message to notaguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
This '88 V6 is about to get improved exhaust manifolds. Based on advice here, I'm leaving the muffler alone. However, I wonder about the cat.

The car was stored in the sun most of its life, and has only 40k miles on it. But time takes its toll...

Is there a non-destructive way to check the catalytic converter?

Thanks!
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84fiero123
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Report this Post04-30-2014 05:57 PM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
a cat usually when it goes will glow cherry red when it get plugged up, that's about all that goes wrong with them, getting plugged up from the platinum falling apart. it will affect drivability as well by not allowing enough exhaust threw it.

Steve

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tebailey
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Report this Post04-30-2014 06:05 PM Click Here to See the Profile for tebaileyClick Here to Email tebaileySend a Private Message to tebaileyEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you tap on them and hear a lot of rattling it's probable bad.
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ag9123
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Report this Post04-30-2014 08:48 PM Click Here to See the Profile for ag9123Click Here to Email ag9123Send a Private Message to ag9123Edit/Delete MessageReply w/QuoteDirect Link to This Post
GM has a TSB ATRATB8730 that explains how to test for a plugged exhaust:



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[This message has been edited by ag9123 (edited 04-30-2014).]

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ltlfrari
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Report this Post04-30-2014 11:43 PM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
Two ways to tell if a cat is bad:

1. It stinks of rotten eggs.
2. Car runs like crap, no power.

Well, that's what happened to mine when the cat died!

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sardonyx247
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Report this Post05-01-2014 01:01 AM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
hook up a vacum gauge, rev and hold the engine to about 2500 rpm, when you are holding it the vac should increse and go back to what it was at idle.
if the vac drops IE: gets closer to zero, you have a pluged cat.

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theogre
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Report this Post05-01-2014 09:57 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Storing doesn't affect catalyst.
Burning oil, coolant from bad head gasket, have ignition/injector problem, will kill them fast.

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redraif
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Report this Post05-01-2014 10:46 AM Click Here to See the Profile for redraifClick Here to Email redraifSend a Private Message to redraifEdit/Delete MessageReply w/QuoteDirect Link to This Post
Can't they also fail without clogging, breaking.... just by the internal brick becoming coated over time and thus no longer exposing the filament that filters the outgoing air. In other words.... you will fail emissions, but the cat it not yet totally restricted. And might you not be able to use a infrared heat gun to detect the temp? Certain temp range is normal, but over that temp means its starting to restrict? Asking cause I have our 93 DelSol that failed and a high nox is typically a cat. However there are some other possiblities it could be... like timing or O2. The O2 was wired wrong when we bought the car and caused a emissions failure. It also resulted in a high NOx reading. So I need to determine a way to verify the cats effective functionality first.

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theogre
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Report this Post05-01-2014 12:01 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by redraif:
1. Can't they also fail without clogging, breaking.... just by the internal brick becoming coated over time and thus no longer exposing the filament that filters the outgoing air. In other words.... you will fail emissions, but the cat it not yet totally restricted. And might you not be able to use a infrared heat gun to detect the temp? Certain temp range is normal, but over that temp means its starting to restrict? Asking cause I have our 93 DelSol that failed and a high nox is typically a cat. However there are some other possiblities it could be... like timing or O2. 2. The O2 was wired wrong when we bought the car and caused a emissions failure. It also resulted in a high NOx reading. So I need to determine a way to verify the cats effective functionality first.

1. Maybe. A sniffer test will show this. Many shops have the tools to check.
2. Bad O2 or wired wrong can kill them. No O2 then always run in open loop mode, can/should set a code in ECM. Wire wrong depend how wrong... O2 is ok but w/o heater then can run in open loop allot longer then normal and could kill the cat. Heater circuit may or not set a code in ECM.
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2.5
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Report this Post05-01-2014 01:02 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Cheap enough i'd just replace it.
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Kevin87FieroGT
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Report this Post05-01-2014 05:15 PM Click Here to See the Profile for Kevin87FieroGTSend a Private Message to Kevin87FieroGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you end out replacing the Cat you might try this one available at Summit and other outlets.

MagnaFlow #53004. 2" inlet, 2" outlet. 13" long, 5.10 x 4.0 diameter. $69.00 (Summit)

Installed on a '86 Pontiac Fiero (2.8L, v6). The smaller size than the flat pan OEM style was welcomed as it allows easy access for servicing the starter and oil filter. It was installed on a straight CAT delete pipe (2" diam.) with OEM muffler. The exhaust note with the MagnaFlow 53004 CAT was softened slightly when compared to the straight pipe and stock muffler combination. It removed all the raspiness at deceleration that straight pipe had. Has a nice deep idle note and no drone noise on the highway making it easy to carry a conversation at 70mph. Additionally, it removed the unburned gas oder at cold idle and had no effect on road performance or mileage over a 600 mile trip right after install. I'm very happy with this. If you want a OEM exhaust note get the flat pan style OEM CAT, but if looking for a slightly deeper note and no raspiness this is the CAT you want. I'm happy!

[This message has been edited by Kevin87FieroGT (edited 05-01-2014).]

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notaguru
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Report this Post05-01-2014 05:28 PM Click Here to See the Profile for notaguruClick Here to visit notaguru's HomePageClick Here to Email notaguruSend a Private Message to notaguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
This thread has been a revelation, and I'm really pleased with the information. I'll soon have new exhaust manifolds on this car, and will do the pressure check as suggested.

Replacing a cat in CA is more than twice as costly as anywhere else.
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Kevin87FieroGT
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Report this Post05-01-2014 05:47 PM Click Here to See the Profile for Kevin87FieroGTSend a Private Message to Kevin87FieroGTEdit/Delete MessageReply w/QuoteDirect Link to This Post
Didn't realize you were in CA. True the Cats cost more there. I believe if you check the Summit site you will find similar ones to the above with and without the O2 lines and ones CA certified. Good luck checking yours, hope you don't need to replace it. Surprising that some last a really long time!
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sardonyx247
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Report this Post05-01-2014 06:00 PM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
To add to the thread, if you have a stock cat on a 4 cyl, duke, it is the old bead type. I can tell you 85% sure it is empty, as the beads wear the blow out of the cat.
I have cut off prob 70 cats and well over half were totaly empty, a few had 'some' in it, none were 'full' only one had about 70% left. This only aplies to the duke's stock cat.
V6s use the honey comb style and this does not apply.
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redraif
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Report this Post05-01-2014 08:46 PM Click Here to See the Profile for redraifClick Here to Email redraifSend a Private Message to redraifEdit/Delete MessageReply w/QuoteDirect Link to This Post
I still have my stock cat. It was full of water.... but still had a ton of beads. How can you tell how many it should have.
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sardonyx247
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Report this Post05-02-2014 06:46 AM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by redraif:

I still have my stock cat. It was full of water.... but still had a ton of beads. How can you tell how many it should have.


If you shake it, (IE off the car) it should be FULL, then go from there to decide how much is in it.
This is more from a scrap perspective, but you get the idea.

Around here you can get a new cat INSTALLED for like $89, including the new cat. So if you ever fail smog in a duke and have a stock cat I would start there.
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redraif
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Report this Post05-02-2014 09:27 AM Click Here to See the Profile for redraifClick Here to Email redraifSend a Private Message to redraifEdit/Delete MessageReply w/QuoteDirect Link to This Post
The fiero is exempt finally. Its old enough. So no worries there. But when i got it we had to cut it off with all my starter issues, plus with water in it... I was afraid to fire it up like that. The mufflers were rusted and full of water as well. Now I just have a straight pipe in its place. From there it goes back to the repurposed Flowmaster I had on my 87 2.8l Firebird. It got a 3.4 and needed an upgrade.
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fastblack
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Report this Post05-03-2014 12:59 AM Click Here to See the Profile for fastblackSend a Private Message to fastblackEdit/Delete MessageReply w/QuoteDirect Link to This Post
Step 1: Move out of CA
Step 2: No more catalytic converter worries...

Honestly, mine has a straight pipe in place of it. But going back to what 2.5 said, cats are pretty cheap and even at double the price I'd say it's worth it if you're already doing exhaust work.
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sardonyx247
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Report this Post05-03-2014 04:24 AM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fastblack:

Step 1: Move out of CA


I tell everyone this step, it fixes Soooo many car problems.

They just don't seem to listen.

The worst one in Cali, if you get caught street racing, they CRUSH your car, so even if they think you are, your car is crushed long before you go to court.
I have a few words to describ the cali car laws, well most of the cali laws, but this is a family forum.
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