alfa 146 2.0 Ti possible cat problems

Sounds like the cat, although a faulty LAMBDA sensor could have/is also to blame. Are you sure the rattle isn't a loose exhaust gasket somewhere or dodgy baffle?

Andy

well, I'm not sure but.... at 50 quid an hour I'd rather have hoped that the Alfa specialist would have been able to tell me that. Don't think I'll be bothering with there service again. I'll get under it soon and see if I can find anything loose. Is there any way to check if the LAMBDA sensor is at fault other than replacing it with another?

Thanks for the help.

I'm not sure, I think you need some specialist gear.

Somebody else on this board is sure to know a way of testing it though.

Andy

Yes, a soft mallet!! Give the cat box a light tap and listen for a secondary sound from inside.

If the Lambda sensor had failed you *will* get the engine management light on.

(1) - Soft mallet. (2) - Go to your friendly MOT tester when the engine is hot - get them to check the emissions to specification - this could show problems with the cat core and/or lambda sensor.

Artie

Yes.

No it won't. I've seen vehicles pass MOT emissions with a cat rattling.

That shouldn't (unless it's blocked) shove your fuelling way dowm, more likely is a duff lamda sensor or a duff temperature sender.You need a better specialist.

Tell me about it. Problem is there are hardly any in my area and the ones there are have a terrible rep or in this case seem to be useless.

I'll elaborate on the syptoms a little more. The car's running is a bit erratic. Most of the time it just seems like it hasn't got the guts it used to. Doens't pull from low revs so well. If I floor it, it does pick up but again not so much as it used to. Occasionally it'll start spluttering, even back fired on one occasion and the the RPM will bounce between about 700 and 1200 if left to idle. Usually a blip on the throttle will cure it. Hot days seem to make this occur more.

I had suspected that the themostat might have been faulty as the temp gauge usually sits at around 70 degrees which seems a bit low to me, especially seeing as midpoint on the gauge is 80. It will get slightly above 80 if sat in a traffic jam but quickly drops once I start moving again. The specialist said this was normal...

I changed the air filter and instantly the car seems to run much better. However, after a day or so any improvment seemed to have been lost.

It flew through the MOT emmisions only a month or so ago.

Thanks for the help guys.

Forgot to mention, the engine management light doens't stay on. Does this mean I can definatly rule out any problems with the Lambda?

Almost a certain that is, the warning lights on Alfas come on for almost no reason, I've not seen any with a failed sensor that didn't put the light on.