Exhaust system
 

Hi All

Xfire has just passed its MOT again, no problems listed. I have however got a very noisy exhaust baffle sound (rattles at certain revs).

MOT guy said there are no loose brackets, clamps or holes.

Has anybody else had this at all and what was your solution?

Cheers
Mark

Re: Exhaust system
 

I believe there is a known fault of rattling cats on some cars, mine never suffered from it, but do a bit of google research on the subject and you might find something.

Re: Exhaust system
 

I had a problem like that on my 87 Mustang a few years ago. It was the material INSIDE the cat had broken loose. Took both off, noise gone. Because of the age of the car I didn't have to worry about emission testing. Your state may be different.
Bill .

Re: Exhaust system
 

He's in the UK so has to have a cat fitted and working, it could however just be something simple like a loose heat shield, but I know when I bought my car back in 2013 I heard stories of Crossfire cats breaking up inside and causing rattles.

Re: Exhaust system
 

Garage has gone over the exhaust system and said it is potentially the cats breaking up, nothing loose or broken externally. I have had a look on the Crossfire Parts list to identify what replacement parts I will require. Can somebody please confirm if I am right with my understanding?

If its the cats, am I looking for items 1 & 2 from the diagram plus items 6, 7 & 8?

I had always assumed the cats came as single items for each side and were just bolted into place, i.e. no pipework came with them.

Many thanks
Mark

Re: Exhaust system
 

This happened on PU truck I had some years ago. Luckily I was able to remove the pipe just after the cat, and remove the loose honeycomb rattling around in there. Chiseled out the rest and no problems since. The omissions program testing had just ended so no problems.

James

Re: Exhaust system
 

Getting rid of the cats is not an option in the UK...it would be a lot easier though.

Re: Exhaust system
 

Any notice in loss of power ?
when they start breaking up, cats usually start plugging up.

did you check all the heat sheilds, they are just attached on the corners.

with just a rattle and no loss of power or mpg I would look at the heat shields, and exhaust hangers.

Re: Exhaust system
 

I didn't say get rid of them, just gut them out and see what happens.

Re: Exhaust system
 

James, Doing anything like that in the UK is not allowed, you would fail the emissions test.

Re: Exhaust system
 

No loss of power, hangers and shields checked and are OK

Re: Exhaust system
 

these are not normal honeycomb cats, they are media, so them breaking up is hard to believe.
I have my secondaries in my shop, if I can get a chance when I get home I will take a pic, if not ight be another week till I get back to my shop.

there is cata clean that runs exhaust hot and cleans cats

Re: Exhaust system
 

I appreciate any help you can offer.

Re: Exhaust system
 

crap, sorry I forgot to take some pics, I was in a rush, got home at 9 pm and me and wife up at 5 for a extended weekend.

I have never had to do inspections, but also if it was a problem with the cats I would think it would show up on the emissions test.

I have seen threads of people talking about rattling cats but have never seen anyone try some cata clean, or some people that have gutted theirs, they never said what the problem actually is with this style of converter, if it is the cats building up hydrocarbons on the media clumping together maybe a cleaner, but again a notice in loss of power would be noticed due to the restriction.

wish I could hear what yours sounds like

Re: Exhaust system
 

Hi Speedy4x4I have tried to use my mobile on video mode to see if it picks up the rattle on the audio, didn't work. will have another try.

Looking at the Exhaust system Figure 11-110 from the parts catalogue, which is the actual cat, is it the units on the downpipes from the exhaust manifold or the two side by side under the centre line?

Re: Exhaust system
 

both, 2 on downpipes and 2 under center of car beside eachother before the y pipe.

some areas can get away with only having 2 and they can take the back pair off.

Re: Exhaust system
 

I have found a U.K. article saying that the Crossfire engine runs very clean and it could be possible that the exhaust gas emissions may be so low that the car would pass the emissions test without the 2 adjacent cats. However the U.K. emissions test requires that the cats must be present and have not been tampered with.

It has been suggested that the two centre line cats are removed, the comb that is causing the rattle is removed, the cats put back and nobody would be any the wiser.

It would be down to the emissions test to see if this is actually the case.

I will keep in digging for more info.

Many thanks

Re: Exhaust system
 

I am from the UK and whilst I haven't removed mine I know a few people who have removed the 2 rear cats and have passed the mot without any problems..

Re: Exhaust system
 

How is it going ?
I just got home and a chance to get a pic today.
I am sorry I was wrong, I was always told they where media cats, and the exhaust shop that took them off said they where media.
but they are honeycomb in the back.
https://cimg8.ibsrv.net/gimg/www.cro...de2d0776cc.jpg
https://cimg4.ibsrv.net/gimg/www.cro...766d8e8197.jpg
https://cimg0.ibsrv.net/gimg/www.cro...225b1a9053.jpg

Re: Exhaust system
 

Hi Speedy4x4

The Xfire went to the garage Wednesday to have minor surgery. Both centre line cats have been "opened" up and either the comb has been removed or welded back into place to stop it rattling. I now have a car that sounds like a car and not an empty tin can full of rusty nails.

The MOT (UK vehicle inspection) is due next May so we will see if it passes the test.

There are no engine management lights on yet, so hopefully all is well.

Many thanks to all that helped out.

Cheers
Mark