Hi everyone!

Regarding the catalytic converter on a Skoda Fabia 1.2 12V from 2003

I've just returned from the mechanic where I spent a fortune replacing the catalytic converter on my Fabia.

(Following a P0420 error.)

But when I came to pick up the car, it wouldn't even start!

Diagnostics shows a whole buch of error codes, from memory:

- Something about fuel mix too rich

- Cylinder 1 misfire

- Something about wrong pressure somewhere

(sorry i dont know so much about it)

Much back and forth, but the shop is having a look at it tomorrow.

But then I suddently got this weird thougth. I have seen the old catalytic converter, and could swear from memory that it had an ~5cm diameter pipe on top of it, that connected it to the plastic cover on top.

Like this: http://www.dataophug...JPG/0A25167.jpg

But now thinking back i could swear that the new catalytic converter didn't have the same pipe on top of it?

Like this: http://i.ebayimg.com...P7igG!~~_35.JPG

The shop is closed now, so I can't check up on it until tomorrow. But.. googling around leaves the impression that there are two types of catalytic converters available for my type/year of car, depending on motor type (AZQ or BME). I've just checked, and my car has the AZQ motor. Is it possible that the mechanic just fitted the wrong catalytic converter, and that is the reason it won't start?

If I'm just totally off track here, do any of you guys have any idea what the problem could be?

The mechanic said something about the egr valve maybe being clogged..

Edited 27 June, 201313 yr by Martin_

the wrong cat will not fit, one is 6v and one 12v physically wont bolt on but it does sound like they may have left the heat sheild off it which has that pipe on.

timing chain problems sometimes start with the cat low efficiency code along with rough idle then they stop running as the chain jumps more, could be somewhere to start from.

Thank you so much for your reply. I spoke to the mechanic today and he told me that he got an error message from the camshaft position sensor as well, which i guess is pointing towards something other than the cat/egr.

Before I took it in it had these symptoms:

P0420 error

Slow response on the throttle

Rough idle

The engine would sometimes cut off when braking eg. for a red light (the revs would just fall to zero and the engine died insted of idling)

The mechanic told me that those symptoms pointed to a faulty cat which has been replaced.

I think I will call to have the car towed to a different mechanic that specializes in skodas on monday. I opted for the cheaper option as it was 'just' the cat (got it oem), but now I'm starting to get worried.. both for my car and my wallet

Is there a way I could check the position of the chain myself without having to open the whole engine?

Again, thank you for your reply. I'd love to hear it if others have thoughts on the symptoms. I will post an update as soon as there is progress..

Edited 28 June, 201313 yr by Martin_

This problem sounds really frustrating and there seems to be some hit and miss guesswork so I hope you get it sorted soon!

Get them to test the fuel pump pressure, I had similar codes and cutting out. Used pump fixed it.

Thanks for the suggestions. I got the the car hauled to the new place today, and I told the mechanic that he should make sure he checked the timing chain and fuel pressure. He said he would, and he seemed pretty confident that he would find the fault. Will update when there is news.

Didn't happen to change the lambda sensors too did you?

A faulty sensor can give all those symptoms.

Day

Didn't happen to change the lambda sensors too did you?

A faulty sensor can give all those symptoms.

Day

 

The guy at the previous autoshop said that he had checked the lambda sensors and cleaned them and that they didn't need to be changed.

...

Is there a way I could check the position of the chain myself without having to open the whole engine?

...

 

Yes, you can:  Post #6 in this rambling thread:http://www.briskoda.net/forums/topic/235977-wideband-lambda-on-12-12v-azq-egr-valve-in-the-end/ shows a cheap and cheerful way I used. There's a few bits you have to get out of the way to get a view of the ends of the cams, but it's easy stuff.

 

You could probably actually do it by eye, without the metal bits I made, 'cos the minimum 'wrongness' of the chain timing is 10° if one of the cam sprockets is a tooth wrong relative to the other (36 teeth on these), and if the chain has jumped on the crank sprocket (18 teeth on this one), the error at the cams will be 20°, which should be easy to see.

The guy at the previous autoshop said that he had checked the lambda sensors and cleaned them and that they didn't need to be changed.

Did he check the values they were recording?

Day

Did he check the values they were recording?

Day

I don't know. Wouldn't it be weird if he said if they were ok if he hadn't checked them?

 

 

 

Anyway I got a call from the shop today and they said that the timing chain needed replacement. And it's going to cost a bloody fortune. Not happy about it, since I just paid a lot of money for a new catalytic converter. But I told them to do it, as I need the car and I don't know what else to do.

 

But.. they said there was the possibility of some valves being busted, but they couldn't check the pressure/condition of them because the timing is off and the valves are open. But they will know after changing the chain, and if they are broken the price of changing them will be more than the catalyst and the chain combined!! Does anyone know how likely this is to happen? If they need replacing I really don't know what to do, as I will soon have paid more than the cars worth in reparations.. :(

Edited 2 July, 201313 yr by Martin_

I don't know. Wouldn't it be weird if he said if they were ok if he hadn't checked them?

 

 

 

Anyway I got a call from the shop today and they said that the timing chain needed replacement. And it's going to cost a bloody fortune. Not happy about it, since I just paid a lot of money for a new catalytic converter. But I told them to do it, as I need the car and I don't know what else to do.

 

But.. they said there was the possibility of some valves being busted, but they couldn't check the pressure/condition of them because the timing is off and the valves are open. But they will know after changing the chain, and if they are broken the price of changing them will be more than the catalyst and the chain combined!! Does anyone know how likely this is to happen? If they need replacing I really don't know what to do, as I will soon have paid more than the cars worth in reparations.. :(

 

I had an issue with my parents RAV4 where it kept throwing up a fault code for the CAT. At £500 it was an expensive repair but it was done. Anyway, less than a month down the line the same fault code came up. The garage who have a very good reputation then said there must be a fault with said CAT. Anyway, another was fitted, around 3 weeks later same issue. Garage then decided to give up with it. All it took was me to hook up my diagnostic machine and check the values and compare to factory readings. It took all of 10 minutes to discover one of the upstream sensors (of 2) was faulty. Garage refused to believe it, yet ordered and fitted a new sensor as a 'goodwill gesture'. Always worth getting a second opinion on things before making any decisions. A quick clean up of the sensor doesnt mean its still reading within spec.

Day

Edited 2 July, 201313 yr by Day-VRS

Also these engines are very prone to valve guide problems , while they have the chain off ask them to take the cam housing off and give the exhaust valves a wiggle side to side. The guides wear that badly you can usually see the movement there even with the springs still on.

Ok, got the car back today. Turns out a worn out chain tensioner was the root of the problem, causing the chain to jump (as "felicia16v" suggested). It was probably not necessary to change the catalytic converter, but too late now.

 

Thank you all for your good suggestions!