Catalytic Question

[gstsaver]

Hi,

If it wasn't for bad luck I would have none at all. My temp fix on the intake didn't last for the roadworthy...which was only 5 km away !
Anyway, I will likely have a replacement intake and gaskets in time.

However, now they are saying my catalytic is rattling. I knew there was an exhaust rattle but that was only after I replaced the rubber hangers so I assume when I was wiggling the exhaust to put it on that it caused something to rattle.
They are saying it is the catalytic that is bad inside and that need to be fixed prior to a roadworthy (safety)...which I need within 2 weeks or I have to pay for a new import cert (VASS which is mucho dinaro) .
Is there a way to tell for sure if it is the cat and not just the heat shield or the bracket/joiner just behind. If I tap the cat on the left side it does rattle but if I tap further back it seems to rattle as well but hard to tell if it is coming from the cat or not ?

Anyway, is there a conclusive test for this ? Also if it is the cat rattling is there a way for a temporary fix ?

 

[Mstng93SSP]

Clamp the shield with vice grips and shake/hit it. If the rattle is gone it's just the shield and can be welded to fix it. I have had shields rattle but never a cat internally.

 

[gstsaver]

Mine seems to have 4 catalytic convertors ? Two strange shaped ones closer to the front and then two regular ones where I expected them. Is this because it comes from California ? When I tap the rear one I hear a rattling (likely not heat shield) but hear the noise louder when I tap the front one on drivers side. Do most have all four cats or is this a california only thing ?

 

[Mustang5L5]

All foxes have 4 cats. The rear ones are the main cats and the front two are the precats used during warmup. Most aftermarket replacement cat pipes are 2-cat pipes.

 

[Noobz347]

Clamp the shield with vice grips and shake/hit it. If the rattle is gone it's just the shield and can be welded to fix it. I have had shields rattle but never a cat internally.

What he said. In all my years on these cars, I've never seen a catalyst break apart without someone actively doing it. The heat shields however, I have cut off of every Fox I've ever owned (or just outright replaced the exhaust).

 

[91TwighlightGT]

What he said. In all my years on these cars, I've never seen a catalyst break apart without someone actively doing it. The heat shields however, I have cut off of every Fox I've ever owned (or just outright replaced the exhaust).

Technically converters can come apart. I’ve seen it on many used cars over the years. Also, if the precat breaks apart the chunks can fall back and clog up the main cat.

Seeing as how these cars are not metered, if there is no tail pipe sniffer then what keeps you from dropping the exhaust, clearing the loose material, and putting it back up?

 

[Noobz347]

Technically converters can come apart. I’ve seen it on many used cars over the years. Also, if the precat breaks apart the chunks can fall back and clog up the main cat.

So have I but not on a Fox. The units used are pretty tough units from the factory.

Seeing as how these cars are not metered, if there is no tail pipe sniffer then what keeps you from dropping the exhaust, clearing the loose material, and putting it back up?

He's trying to pass emissions. Depending on where he lives, that can mean different things from a visual inspection all the way through a sniff test to ensure the vehicle meets the standard established when it was manufactured.

 

[91TwighlightGT]

So have I but not on a Fox. The units used are pretty tough units from the factory.


He's trying to pass emissions. Depending on where he lives, that can mean different things from a visual inspection all the way through a sniff test to ensure the vehicle meets the standard established when it was manufactured.

Right, agreed and understood. However, he mentioned it was for a roadworthiness (safety) inspection. Basically, if there is not an emissions test then he should be able to clear it out if there is debris in it.

Naturally, if he needs to pass a sniffer then he will have to replace the converter if it is broken up.

 

[Mustang5L5]

Right, agreed and understood. However, he mentioned it was for a roadworthiness (safety) inspection. Basically, if there is not an emissions test then he should be able to clear it out if there is debris in it.

Naturally, if he needs to pass a sniffer then he will have to replace the converter if it is broken up.

I agree. If he doesn't need to pass an actual sniffer test, i'd pull the pipe off, located the broken converter and break it up and remove it and reinstall.

 

[General karthief]

He is in Australia, they are pretty strick, this is so he can register the car,

 

[Noobz347]

He is in Australia, they are pretty strick, this is so he can register the car,

The real kick in the balls is that their emissions requirements are twice the haphazard mess that ours is. I've heard it said that not only are requirements different from state to state but it that it's difficult to often find the standards that apply to you and can even then vary from city to city or town to town.

I would give up. It's already a PITA in the US.

 

[gstsaver]

The car was supposed to have a sniff test before the first Certificate I got (complies in Australia) but didn't and yet they gave me the certificate. The issue is if they somehow pick this up at the state registration office then I would be cooked if I deleted the catalytic.

It is 99% the left front 'little' catalytic that is broken inside. It doesn't seem to rattle much when cold, only after heating up.
I think I will try going somewhere else for the roadworthy, book it in for the afternoon and drop it off in the morning.

Also my gaskets aren't going to be here in time for the intake (found someone in the country with the actual intake which will be here in days)..so a temporary fix again for the coolant leak will hopefully this time hold up.

It isn't that I am trying to get away with doing it on the cheap I just only have another 2 weeks from my first certificate to get it registered or I need to get the first certificate done all over again for big cost.

BTW - if I get it passed for roadworthy and then want to get rid of the rattle - I know one open is to hollow it out but is another option to just get it removed and put a pipe in? The replacement full catalytic appear to have only the two cats and not the front ones - what happens with the oxygen sensors if the front ones are removed ? Won't the check engine light come on ?

 

[91TwighlightGT]

It's an OBD-I system, so their is no monitor of catalyst efficiency. In an OBD-II system, the front O2 sensors are measuring air/fuel ratio, while the rear O2 sensors are measuring the efficiency of the catalyst.

So, in short, the O2 sensors are not affected by the removing of the catalyst.

 

[gstsaver]

Ok thanks guys. I changed my mind as i had some free time today and tried to remove the exhaust. It just doesn't want to come off !

All the bolts are off pretty easy BUT I believe it is the smog tube stuck on not allowing it to come off. I have tried prying everything off but if just won't come off. I can't see it hung up anywhere and it looks like it should just slide off the hangers. Sprayed lubricant on the hangers, spayed lubricant around smog tube..and then even tried heating up where the smog tube goes into exhaust..red hot and yet no luck !
I tried prying off and it just doesn't move much at all.

Any tips on removing this ?? If not I will give up and put back together and go with plan A.

 

[Steel1]

You could always cut the smog tube just in front of where it connects to the mid pipe,
leaving yourself enough room to re-connect with a piece of heater hose.
I ran for years like this with no issue.
I believe the smog tube is held on with a one bolt clamp, but even when loose they
can still be pinch on a difficult to remove.

 

[Mustang5L5]

Agree. Cut the tube, and then when you reattach, use a piece of heater hose and two hose clamps. I've run this way for at least a decade