Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[mkaminski100]

I have a question regarding blocked catalytic converters. I know that when these are blocked, car is not accelerating, smells like old eggs when running. What about petrol consumption, emission test and exhaust gases temp when exiting back box?
My car runs poor (poor on power and poor on petrol consumption), has problems when accelerating and smells eggs when driving fast (revs 3000). I am sure it’s burning oil – blue smoke during start up (stem seals which will be replaced soon). Emission was ok and well under the limit.

[cem_devecioglu]

Catalytic converters are designed for lifetime (says the book) and

when I cut them down (some stupid people said it may help the car to

go freely  )  I see they are not blocked and not easy to block them..

Dont touch them until a trustable proffesional approve..

[Entwood]

AFAIK the cats don't block ... but certainly the back box does/can !!! On the old miggy the performance suddenly dropped badly, no guts, high fuel consumption (probably due to over use of the right boot to try and get anywhere) - never noticed any smell mind

Whilst investigating the front end - spark, fuel etc etc - my SWTSMBO asks "should you have all that crap hanging out of the exhaust ?" ... there was a huge lump of wadding/wirewool type stuff hanging out the back end, gave it a tug and it just kept coming and coming ... about a carrier bag full !!

It was the internals of the back box ... new box and the performance recovered instantly  

[FRE07962128]

I have a question regarding blocked catalytic converters. I know that when these are blocked, car is not accelerating, smells like old eggs when running. What about petrol consumption, emission test and exhaust gases temp when exiting back box?
My car runs poor (poor on power and poor on petrol consumption), has problems when accelerating and smells eggs when driving fast (revs 3000). I am sure it’s burning oil – blue smoke during start up (stem seals which will be replaced soon). Emission was ok and well under the limit.

If your car is running as badly as you describe it is very possible that your cats have been badly damaged by excessive amounts of unburnt fuel.  

My personal experience is that cats do need replacing on your car after 80/100k miles, at least mine did on my Carltons, Senator and Omega after about that mileage.  When were yours last replaced?

Therefore sort your engine out then replace cats.  That's my recommendation ONCE you have checked everything else out like the exhaust as already stated.

[Mike Collins]

Hmm,,,, current 2.6, 140,000, original exhaust/cats. Previous 2.5, 200,000, original cats and probably exhaust. Wife's 2.5, 240,000, look like original cats to me.

Fairly robust in my experience.

[FRE07962128]

Hmm,,,, current 2.6, 140,000, original exhaust/cats. Previous 2.5, 200,000, original cats and probably exhaust. Wife's 2.5, 240,000, look like original cats to me.

Fairly robust in my experience.

You have been lucky then, but I have never had that luck!  Every one of my cat fitted cars eventually required new cats.  Maybe modern ones have improved their life span, but one thing for sure excessive unburnt fuel will damage them.

[Mike Collins]

If I add to that list a Peugeot 405, 200,000, original cat, lots of silencers and pipes though.

What may be significant is that my cars almost never do short journeys. 25-35K/year is normal.

[FRE07962128]

If I add to that list a Peugeot 405, 200,000, original cat, lots of silencers and pipes though.

What may be significant is that my cars almost never do short journeys. 25-35K/year is normal.

That would make a big diffence, like with the rest of the car Mike.

[trebor]

mine died, have done 186k. replaced with bypass pipes   8-)

[FRE07962128]

mine died, have done 186k. replaced with bypass pipes   8-)

Is that legal on post 1991 cars Trebor?

[trebor]

When you run on lpg it is  8-)

[FRE07962128]

When you run on lpg it is  8-)

Right another good saving in having LPG!!

[trebor]

yep!  and sounds very sporty too now!

thought I might as well do it especially as both cats were knackered.

[Marks DTM Calib]

Hmm,,,, current 2.6, 140,000, original exhaust/cats. Previous 2.5, 200,000, original cats and probably exhaust. Wife's 2.5, 240,000, look like original cats to me.

Fairly robust in my experience.

You have been lucky then, but I have never had that luck!  Every one of my cat fitted cars eventually required new cats.  Maybe modern ones have improved their life span, but one thing for sure excessive unburnt fuel will damage them.

Nah, the cats will last the life of the car if they are not exposed to in-correct mixtures or physical damage.

The Carlton and Senator engines were not so efficient with pretty naff lambda control setups and hecne why they probably didn't last so long.

I have seen them block on Cav's but, its normally following a miss fire or similar issue.

[mkaminski100]

Uff… I had a very hard day yesterday. I just wanted to explain my theories and what I want to do. It’s not my intention to remove the catalytic  converter. Car would not pass MOT and would become very loud. There is a way to check condition of the cat, but the flexi joint needs to be replaced then. I don’t know any good and cheap welder to do it.
As per cats you all are right. It’s not the millage or age that damages your cat – it’s oil and petrol that will melt ceramic insert and clog it. So, some people might do 200k and it will be fine, and in some cases it can only do 80k and die.
Why I am writing this? Because I took the engine head out yesterday. Oil was black and greasy. There was a lot of greased oil. Tops of pistons are black but dry and without any deposits. Valves from cylinder side are white and clean (same colour). Unfortunately 6 exhaust valve stems (can see it from exhaust) are covered with fresh and burned oil. So it’s burning oil. Stem seals can be removed without any force (suspiciously it’s Elring) and rubber is very hard and break easily. I was aware that it needs attention but was very surprised to find something like this.
Now I am not sure if it’s mid box or cat. It can be cat, as my car is burning a lot of oil, but it can also be mid box, as it’s noisy when under load (driving). As soon as I will finish my engine head I will have to investigate further and if I’ll find out what the problem was, I will find something else that needs attention…. Never ending story.