Limp Mode............ Help Please

[S2 Ant]

Over the last couple of weeks i've noticed a kinda rattling noise from under the car, sounds like its coming from the CAT section of the exhaust, either there or between there and the downpipe.... Its not loose or anything, so am guessing the CAT has kinda fallen apart.... is this possible?

Anyways, its got a bit worse now and rattles more often then last night my lovely car tried to kill me by trying to put me thru the windscreen at 3000 RPM.... Could this rattle be related to the limp mode thing, or likely to be 2 separate issues (at a guess of course)

Assuming its the CATs that have gone **** up, would the CAT replacement pipes meet up with the existing downpipe and exhaust? (so i only have to buy the CAT section rather than the whole thing, cos i'm proper skint )

Thanks guys!!

[Mihnea]

Ant, I don't think both issues are related. The engine cut-out at 3k is ECU protection, sounds like a rather big (but not as big as Tom's) air leak through an intake hose, the rattling might indeed be the cats falling into pieces but they can't be related to each other IMHO/IME....


HTH,


Mihnea

[S2 Ant]

Okey Dokey... Thank you........ Time for some invesigation...... And as per usual British weather lives up to usual standards.... Its Pi**ing Down!!!

Oh well.....

[audiman]

No one will beat my leak!!

I think Mihnea is right, sounds like a boost leak
Maybe time for some Samcos?? Just use the plastic friend!!
Cats would not cause this sort of problem. On the subject of de-cats im not sure if the ABY cats are seperate from the downpipe? Never seen one. But for the 3B they just unbolt and you put in the two pipes in there place. Easy!

[Graham]

The cats are separate items from the downpipes on the ABY, the joints on mine ate well ground from the odd bottom out, plus the exhaust is hangin low
Graham

[Dr H]

Yep ABY cats are sparate. S2 Ant if you need to borrow (or buy) a decat pipe I have one. It's SS and allows to to take the CATS and rear Y peice off in one go.

Not the best decat pipe in the world but It'll do the job

[S2 Ant]

Cool... If it fits then how much are you wanting? Cos i'm wanting to ditch the things anyway!!

Gonna go leak hunting tomorrow... assuming i get out of bed before its dark LOL

Cheers guys!!

[A6 AVANT]

Your CAT may be collapsing, if the rattle is coming from the cat then it sounds like the honeycomb internals have broken up. If a large enough piece has broken it can turn inside and when you accelerate it gets pushed to the back of the housing and blocks the exhaust causing the loss of power. This has happened numerous times with cars that have been brought to our garage with loss of power over 2k rpm and a rattle from cat.
3 options available.... 1, take off cat and smash it through so you get clean flow. 2.replace cat! possibly quite expensive, I am sure some of the other guys can advise you on cost. 3.take off cats and replace with through pipes.
I would probably sort the cats before looking for a leak as I think this is your problem. Audiman knows all about leaks!!!! His was a real b/tch!
Let us know how you get on.