Emission warning light? New Cat?

Emission warning light? New Cat?

Author
Discussion

baronvonhorne

Original Poster:

63 posts

240 months

Tuesday 19th December 2006
quotequote all
Hi all,

I have a 2001 330ci with rather high miles (110,000) - FSH, mostly motorway miles.

Recently the emission warning light has come on - I have had it checked, but at first nothing found and the light went out.

It came on again and was again re-checked - the fault was 'sporadic' and linked to the cat.

The dealer thinks I need a new cat (apx GB1500), but a new cat at 110,000 miles sounds strange. I have had cars with nearly 200,000 on and no probs with the cat.

Any thoughts? What about damage which may be caused if I do nothing about it?

Cheers for any advice!

jay123

161 posts

214 months

Tuesday 19th December 2006
quotequote all
how does the car run...

usually if the cat is knackered you may be able to hear the matrix inside rattle when you go over bumps or similar.

Onetone

37 posts

218 months

Tuesday 19th December 2006
quotequote all
Had something similar in the past - turned out to be an 'engine intake manifold flap motor sensor fault', or something along those lines (all the right words but maybe not in the right order) - honestly can't remember the precise wording. Regardless, fault was sporadic and very cheap to repair, albeit done under warranty.

I would think a knackered cat would manifest itself as a permanent fault!

However, if it really is the cat, based on bitter (expensive) experience, I would seriously consider changing your car asap, as other things are likely to start going wrong soon - and remember, no warranty in the world covers for failure due to normal wear and tear.

blackspider

1,038 posts

215 months

Tuesday 19th December 2006
quotequote all
The 330i has 2 pre cats-one in each manifold and then a secondary cat further down..We rarely get problems with cats.
If there is a problem with on of the cats you tend rattling from the exhaust if you bang it-when a cat fails it breaks up.However sometimes they do go porrus and the honey comb cracks but stays in one piece.Because these engines are efficient it will more than likely run without fault and pass emissions even though it has a cat failure-They should be able to see if the cats ok as there a 2 lambda probes(4 in all-2 pre cats and 2 after cats) that sit after the cats,these are redundant until the cat fails-they will read 0.7v constant with a good cat-if the cat fails then they will read 0.2 to 1v fluctuating,this should be visable from a GT1 diagnostic machine.
From experience the faults I tend to find are;
1,the rubber crank case breather pipe that runs across the top of the inlet manifold(under top plastic cover)tends to collapse and suck in-engine cant breath,runs rich and EML light comes on-they modified this to a plastic pipe.
2,the cyclone oil seperator under the inlet manifold cracks.
3,the DISA in the inlet manifold splits.
4,Air leak to manifold(vacuum pipe,edk motor seal-throttle etc)
5,irratic heating element in one of the lambda probes.
6,Air mass meter

n3il123

2,667 posts

219 months

Wednesday 20th December 2006
quotequote all
I had the same thing on my 535 was caused by a split in one of the hoses... took the dealer (warranty job) about 4 days to find it in total...

baronvonhorne

Original Poster:

63 posts

240 months

Wednesday 20th December 2006
quotequote all
Cheers guys - much appreciated.

The car is running very nicely - no noticable changes at all.

I guess I'll do nothing at this stage unless it starts behaving unusually.

Thanks again.