Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: mkaminski100 on 15 July 2008, 15:22:46
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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.
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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..
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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 :y :y
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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. :y That's my recommendation ONCE you have checked everything else out like the exhaust as already stated.
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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.
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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.
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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.
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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. :y :y
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mine died, have done 186k. replaced with bypass pipes 8-)
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mine died, have done 186k. replaced with bypass pipes 8-)
Is that legal on post 1991 cars Trebor?
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When you run on lpg it is 8-)
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When you run on lpg it is 8-)
Right another good saving in having LPG!! :y :y
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yep! and sounds very sporty too now! :)
thought I might as well do it especially as both cats were knackered.
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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.
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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. :(
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Flexi joint is easy to replace and you can get stainless clamp in sections for around 20-25 quid.
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Flexi joint is easy to replace and you can get stainless clamp in sections for around 20-25 quid.
Hack saw is good enough to cat it but I am concerned if clamp will survive this pressure. Will it not leak?
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Just to tell my experience , whatever I use instead of original cats ,
the welding areas sooner or later leak ..Yes even the electrical welding
dont keep long (few months) .. And when it does, consumption go crazy :'(
They say the original gm exhaust is chrome alloy so welding dont
keep long :-?
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I am also concerned about that. Best way would be to use a camera on long lead to drop it from downpipe side and check if cat is knackered. Otherwise it’s the mid section. Cheap mid box cost £30 (in some places £50-60), Bosal is £60, and GM with TC is ca £80. It’s a lot just to check something. Catalytic converter (whole section) is about £250. Bit expensive to make probes and check which is knackered…
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Any ideas on how to check which exhaust part is blocked without cutting it or replacing?
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Any ideas on how to check which exhaust part is blocked without cutting it or replacing?
Take the cat off an blow through it.....dead obvious when there is any restriction.
As for the flexi joint, I thought you were referring to the flexi piece in the front pipe failing.
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Any ideas on how to check which exhaust part is blocked without cutting it or replacing?
Take the cat off an blow through it.....dead obvious when there is any restriction.
As for the flexi joint, I thought you were referring to the flexi piece in the front pipe failing.
There is no leak in exhaust, but to check if cat is blocked I would have to cut pipe in upstream the cat (where the joint is). I any situation it’s good to change flexi joint (upstream the cat).
I think that cat would have to be completely clogged if I wouldn’t be able to blow (would explode when driving).
There is no other way to find out which box is blocked than to cut it or replace it…
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For a meagre price compared to the alternatives, you could try some Cataclean. Those nice chaps on the TV keep on about how good Cataclean is for your exact problem :) :) :)
A regular and sprited drive in the country is probably just as good at keeping your cats clean.
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Trying to think of the stuff, but there is a "magic lotion" which does actually seem to bring dead cats back from the dead - I think made by Forte?
A lot of times, an "italian decoke" can reap wonders..but beware that if your exhaust is on its last legs, it will probably spit its stuffing out - in which case it's knackered anyway.
Its amazing how much more a rusted, dead exhaust weighs than a new one - all the trapped carbon.
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I am not sure that it makes those miracles that they advertise…
http://www.lexusownersclub.co.uk/forum/lofiversion/index.php/t14124.html
http://www.lexusownersclub.co.uk/forum/lofiversion/index.php/t13642.html
I will try to drive it for a while and do the emission test. If it will be under the limit then mid section is knackered and needs replacing.