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What are some symptoms of a clogged catalytic converter on 2.5 Duke? by mckaymotoworks
Started on: 10-28-2014 01:38 PM
Replies: 11 (362 views)
Last post by: Diamond Dave on 10-31-2014 07:52 AM
mckaymotoworks
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Report this Post10-28-2014 01:38 PM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
Besides those usually associated with other or later model cars? I ask because the manifold nor temp seem to increase, nor do I have decrease in mileage
But the car is sluggish on the throttle, I know the AT is a slug, but the car was much more responsive in the very beginning, even with bad sensors, few codes.

All sensors have been replaced, new coil, wires plugs etc. Car idles like a top, good mileage 27-30, no codes, no stuttering, odd idle etc. I do smell the telltale sign ever so often, not heavy, but comes and goes. It just feels like an anchor is attached to it at time. No parking brake for now, new brakes and lines, calipers aren't dragging, new bearings etc.

I do plan to swap to Magnaflow cat and muffler with custom mandrel SS pipe very soon as I am restoring the car, want it breathing better and looking nicer.

Car is an 84' SE with a M19 swap soon.
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jaskispyder
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Report this Post10-28-2014 01:57 PM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
pound on the cat (with your hand) and see if it sounds like sand in there. They used pellets and if they are still moving around, the cat may still be OK. Hard to say without some tools to test for backpressure. If your MPG is good and such, it is probably ok, but it is old and changing it out will be a good thing.

[This message has been edited by jaskispyder (edited 10-28-2014).]

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mckaymotoworks
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Report this Post10-28-2014 01:58 PM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
Agreed. If I can hurry and find the elusive Holley setup knock all that out at once, I'll move on to the transmission swap and suspension.
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Dennis LaGrua
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Report this Post10-28-2014 10:11 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
Remove the O2 sensor. The car can start without it. Attach a common compression gauge. It will thread in to the Oxygen sensor hole. Start the engine, rev it and watch the gauge. Anymore than a pound of back pressure is an indicator of a plugged exhaust/CAT.
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Grizz54
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Report this Post10-28-2014 11:02 PM Click Here to See the Profile for Grizz54Click Here to Email Grizz54Send a Private Message to Grizz54Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:

Remove the O2 sensor. The car can start without it. Attach a common compression gauge. It will thread in to the Oxygen sensor hole. Start the engine, rev it and watch the gauge. Anymore than a pound of back pressure is an indicator of a plugged exhaust/CAT.


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Grizz54
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Report this Post10-28-2014 11:06 PM Click Here to See the Profile for Grizz54Click Here to Email Grizz54Send a Private Message to Grizz54Edit/Delete MessageReply w/QuoteDirect Link to This Post

Grizz54

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quote
Originally posted by Dennis LaGrua:

Remove the O2 sensor. The car can start without it. Attach a common compression gauge. It will thread in to the Oxygen sensor hole. Start the engine, rev it and watch the gauge. Anymore than a pound of back pressure is an indicator of a plugged exhaust/CAT.


Agreed. This is probably the best way to check for clogged cat. But, If you don't have a compression gauge and you do have a vacuum gauge, you can connect it to a good vacuum source, slowly increase the rpms to 2500 -3000 and watch the gauge. If the vacuum reading decreases as the rpm increases you may have a plugged cat.
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mckaymotoworks
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Report this Post10-29-2014 09:24 AM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
Excellent suggestions! But may be replacing sooner, got pulled over this morning for my antique tag. lol
So I will have to go through emissions for a regular tag. Fingers crossed since all my sensors are new.....


The man ALWAYS wants his money
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mckaymotoworks
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Report this Post10-29-2014 01:10 PM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
Also forgot to mention I checked fuel pressure at idle and under load a few months back. In regards to sluggish throttle.
Hopefully, it will pass tomorrow, get new cat next week, see if that wakes it up.

[This message has been edited by mckaymotoworks (edited 10-29-2014).]

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mckaymotoworks
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Report this Post10-30-2014 10:58 AM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
Passed emissions with flying colors. So maybe the transmission, though a slug by nature, is at fault.
I will look at adjusting the shift and throttle sync, but other than that, no use since the 4 speed will be going in.
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jaskispyder
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Report this Post10-30-2014 12:19 PM Click Here to See the Profile for jaskispyderSend a Private Message to jaskispyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by mckaymotoworks:

Passed emissions with flying colors. So maybe the transmission, though a slug by nature, is at fault.
I will look at adjusting the shift and throttle sync, but other than that, no use since the 4 speed will be going in.


Auto tranny? Yeah..... slow... very slow

Just put the 4speed in there... things should get better.
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mckaymotoworks
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Report this Post10-30-2014 12:21 PM Click Here to See the Profile for mckaymotoworksClick Here to visit mckaymotoworks's HomePageSend a Private Message to mckaymotoworksEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by jaskispyder:


Auto tranny? Yeah..... slow... very slow

Just put the 4speed in there... things should get better.


I totally agree. But I am not crazy,lol, it did accelerate better at one point. As said, won't waste much time chasing it since swap is pending
I have to get my 86' CRX Si back up so I can get to work on the Fiero.
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Report this Post10-31-2014 07:52 AM Click Here to See the Profile for Diamond DaveSend a Private Message to Diamond DaveEdit/Delete MessageReply w/QuoteDirect Link to This Post
Equipment gets old and plugged up. Dauh. Hyperformanceliw cats have been kicking but for many years. There is a couple old clowns who disagree but thankfully they are minority. Cats come in high flow configurations and will kick but on straight open pipies. I love wbay my Magna flow mufflers do and my cats yeeowl.
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