Pipes Been Blasted Off. Catalytic Converter Faulty?

[forfpablo]

2.3i Ghia x 1998 Manual Petrol

 

Hi all, if I suspected that my cat was faulty, how could I check - other than banging it and hearing it rattle?

My current problem is severe drop in power, and almost stalling if you try to accelerate too hard. I can only get about 20 mph at the mo.

There are two T's that branch off of the exhaust manifold piping, that connect to what I think is a pressure differential sensor in the battery compartment via a figure of 8 rubber tubing. Every time I start the car the tubes connecting to the T's get blasted off and the exhaust gases come out of the T's at a very high pressure.

 

I have removed the EGR valve and sucked on the diaphragm and the needle moves up and down, so I guess it's not the valve.

I ran the engine with the valve completely removed and it was a bit better but still suffering.

 

My question is what would have to happen to enable the tubes to be blasted off the manifold.

It seems like the only place that the exhaust emissions can exit the system is via the two little T's.

 

Does this suggest that my exhaust is blocked, or that my Cat may have collapsed ?

 

I put my hand over the tailpipe while the engine was running, and I have to say there didn't seem to be a lot coming out of it.

I wondered if that was because the exhaust gas was escaping through the T's under the bonnet.

 

If I block the T's to stop the exhaust gases from getting out of them, the car just stalls and chokes itself.

Has anyone had similar experiences, or could they point me in the best direction to try and isolate the problem.

 

My next step of self diagnosis is to take the cat off and peer inside. Will the car engine run with the cat removed, so that I can make a comparison ?

Any help or guidence greatly received.

Thanks.

[forfpablo]

Hello, it's Billy no mates here :lol:

No one gonna help me :lol:

[mumof4]

hmmmm.....not knowing much about what your talking about...BUT.....my wee veccy did drive on its test drive with a knackered cat, the garage at the time didnt know it was naffed.It just sounded reallly loud to me, gutteral even??

 

i am assumeing..the car will run with the cat removed, as isnt the cat there to aid emissions??

 

It does sound like there is a blockage somewhere to me.is it possible to blast some air down the pipes to see?? But that may push any blockage further up yes??

 

Hmm..sorry i cant be of more help. :lol:

[forfpablo]

Hi Mumof4, (that makes me Dadof5) thanks for replying, it was lonely here in the dark :lol:

 

I'm not sure how the engine would behave with the exhaust off, as these days pressures in the system seem to be all important.

The cat removed would make an adjustment to the pressure, then there's the Lambda sensor which might get upset.

 

I'll obviously give it a go, I was just wondering if it was going to be a pointless exercise ! :lol:

 

I am really puzzled as to why the pipes are getting blasted off and what is making it happen.

 

These two little rubber pipes about 12 inches long, cost me

[johnb80]

It sounds very much like a blocked cat OR a blockage further down the system. The CAT is the most likely candidate. I would imagine the sensor is there to detect the CAT becoming blocked, maybe yours wasn't working! I would not blow air into the sensor pipes. You need to remove the cat and have a look at it, make sure the rest of the exhaust is clear. You could knock the honeycomb out of the CAT and put it back on to get you mobile until a new cat can be obtained. I would suggest you look on the net for a cat NOT the local stealer.

 

Regards - J

[forfpablo]

Hi John,

 

it's great to get peoples opinions here on the forum. I thought the senor was just taking pressure reading from

the exhaust manifold and sending info back to the ECU, which in turn would be adjusting fuel mix and controlling the

EGR valve and all that technical stuff. :lol:

 

It

Edited February 5, 2008 by forfpablo

[forfpablo]

Hello to all.

Just an update of the pipes being blasted off/lack of power problem. :(

On the weekend I convinced myself that the only reason for the vacuum pipes being blasted off the exhaust manifold must be down to a blocked exhaust. I then took the angle grinder to the exhaust and cut the Cat out. :D

 

It is with great relief, that I can tell you all, the Cat was blocked solid and the monolith had broken down severely. There was no sign of daylight through the Cat, it was completely solid. I am attempting to add some pics here for all those would have asked about Cats and what they look like when they turn ugly. I ran the engine without the exhaust and it was back to normal. Prior to Cat removal I could only get a lumpy 2000 rpm, and shortly after, total engine failure. This has explained why the vacuum pies were being blasted off of the exhaust manifold. The exhaust gases had no exit, so they were expelled through the vacuum branches.

 

I

[?Bleeno?]

Glad to hear you've found the problem Paul and the information you've obtained will be very useful to the forum. I'm pretty certain you can get the whole exhaust cheaper than that from Kwik Fit and IIRC there's a company up North somewhere that is very reasonable as a freind of mine bought a full stainless steel system for his Beemer for the same price of a standard system. So if you shop around you'll find what you need I'm sure of that.

[gregers]

at the mo there seems to be a lot of exhuast parts for sale on ebay,perhaps you could make a complete one up yourself and save a fortune in the process????

[forfpablo]

Thanks Gregers,

I did have a look on there today and the company I was asking about 'ONLINE AUTOMOTIVE' are actually on there !!

They've got an excellent feedback rating and lots of good comments. So it looks like I'll be placing an order with them tomorrow for a complete exhaust and Cat for

[forfpablo]

Pictures of my blocked Cat and what came out when tipped up.

 

http://i52.photobucket.com/albums/g11/pab_photos/galaxy/P2090022.jpg

 

http://i52.photobucket.com/albums/g11/pab_photos/galaxy/P2090016.jpg

[johnb80]

Just make sure there are no under lying problems that blocked the 1st CAT, you don't want it happening again!!!!

 

Regards - J

[forfpablo]

Yeah, I know that it was only firing on 3 cylinders for a fair while before this happened, so I guess the unspent fuel is the culprit.

I am sure I read on this forum, or it may have been another, that the fuel management system stopped supplying fuel to any cylinder that wasn't firing. :)

 

I am not sure about that, it seems a bit unlikely to me, maybe someone could confirm.

 

My main concern, when I put it all back together, is what else might have been affected. The vaccum sensor was receiving extreme heat front the exhaust

manifold, which it was never ment to get, and may be damaged. There's probably a lot of coke or carbon deposits in the manifold and pots too. I'm not sure of the best way to claen it.

Where I've removed the front pipe from the manifold, there's a lot of black sooty deposits, which I don't want to send down to my new Cat.

 

If anyone has any guidence for me or can recommend a product that you used and has helped/done the job, I would be greatful.

 

Maybe I could run the engine for a couple of days without the Cat and just put a dummy pipe in it's place, this might let me blast some of the deposits out.

Any other ideas anyone ?

 

What about my Lambda sensor ? Should I replace it or just transfer the old one ?

[forfpablo]

Just a final update.

 

I bought the complete exhaust system from www.onlineautomotive.co.uk for

[mossy65]

Cats are a problem with every ford I have had. Had one exit throught the tail pipe once, left a loverly cloud of white dust in the air. Found a replacement cat on line for