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E51 The E51 Catalytic Converter Problem

Thank you very much Karl. Sorry, I didn't mean to give the impression that I hadn't read the thread before asking -- I was just trying to get a bit clearer on how this would effect MOT. It sounds like the best option is to de-core the rear cats (I assume they are towards the back?) as this would be stealthier. I will likely only own the car for a year (have to get it back to the UK whereas I am staying in Europe); and it has approx 45k miles on it so I'll take the path of least resistance.

Thanks for starting up this forum, it's incredibly useful!
 
The rear cats are roughly in line with the front seats... but underneath the vehicle obviously.
 
I haven't de-cored my cats yet, will be doing when I get a bit of time but I don't see it as quite the priority that most people seem to see it. On most cars the most likely reason for cat failure is incorrect fuel mixture (too rich) but on most cars the MIL light is far more likely to come on in the event of incorrect mixture. I know my lambda probes etc are working properly, checked the fuelling and it's OK, but I've seen a few Elgrands with duff lambda probes / duff MAFs that have caused incorrect mixture and the MIL hasn't been on. I can tell just by driving a car if cats are clogged and wouldn't tickle the throttle or drive far with clogged cats. Another test for clogged cats is if exhaust gasses seem to be hotter than usual and coming out more slowly and/or the engine doesn't draw as much vacuum as it should. Can't imagine having cats clogged enough to cause engine damage and not noticing it tbh. A properly installed and calibrated LPG install doesn't make cat failure more likely, most likely the opposite, but I have seen plenty LPG installs that are setup too rich (particularly under high engine load open loop fuelling conditions) that could make cat failure more likely.

Edit September 2018.. I wrote the above just a couple of months before my engine was wrecked as a result of driving with blocked cats. I did notice the problem while driving (the drop of power) but was in a driving situation where I couldn't just pull over at anytime or nurse the car by only using light throttle. See page 9.
 
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Karl said:
Please, for the benefit of all of us, go and stamp on his fucking head!

Yes, they need de-coring. The 2.5 has the same quad cat set up as the 3.5. The recall does NOT fix the problem, it just prolongs the inevitable.

The front cores will still break up, they will still get trapped in the 2nd cores, and your engine will still blow up.

As it's LPG converted, might as well get all 4 done and save the shit being blown out the back of the exhaust when the front cats do give up.
Click to expand...

So - just because someone who doesn’t agree with your opinion about de-coring cats deserves his head jumping on? What a cretinous thing to say....Personally, I’m getting a bit fed up of a minority of so called experts on here trumpeting on about the inevitability of any Elgrand that doesn’t decore cats suffering catastrophic engine failure. What utter bollocks.

We live in a democracy, mate, & my opinion as well as any others are just as valid as anyone else’s. Get a grip.
 
Karl said:
Please, for the benefit of all of us, go and stamp on his fucking head!
Click to expand...
This is why I love this forum :joy: My LPG E51 also came from Phil @ JAL. I have had the rear cats done by @Winchester and don't regret it at all. The cats removed were in excellent condition which shows that the front cats were nowhere near breaking up but I would rather listen to the advice of people who know their stuff and have experienced than take an unnecessary risk.
 
Reuben said:
So - just because someone who doesn’t agree with your opinion about de-coring cats deserves his head jumping on? What a cretinous thing to say....Personally, I’m getting a bit fed up of a minority of so called experts on here trumpeting on about the inevitability of any Elgrand that doesn’t decore cats suffering catastrophic engine failure. What utter bollocks.

We live in a democracy, mate, & my opinion as well as any others are just as valid as anyone else’s. Get a grip.
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Yes, because it's bad advice.

It might be a small group of people who constantly rant about it, but how many engines would have blown up if the warnings were not there?

I know of at least a dozen of these engines that have popped due to cat blockage. That's just me. One person.

That's 12 people who have either sold their car as scrap, or paid £2500-£4500 for a replacement/rebuild of an engine.

That's a LOT of money to most people, and if I've saved ONE person from having to spend that money for the advice I've given, then I'm happy.

I had a Peugeot 306 diesel once, and you could manually alter the turbo and fuelling to get more bhp. I did not know, however, that there were different revisions of the same engine, and the one I had would shoot a rod if tweaked. I tweaked it, and piston #1 shit itself. I scrapped that car because it wasn't worth replacing, but I wish someone had ranted and raved about it as it might have saved me a whole lot of money and hassle at the time.

The rear cats blocking is NOT an opinion. It is a fact. It does happen, and it does kill engines.

If you don't like hearing about it, leave. Otherwise, ignore it, because other people DO appreciate being warned of potential dangers with their cars.

Edit: No I do not condone physical violence. It was a comment made in jest. So take a break from the keyboard bud and have a beer, chill out and don't get wound up by things someone said on the Internet.
 
Not much point putting an afterthought in about not condoning physical violence when the first 5 words of your post show that you do. Thanks for your advice regarding my mental wellbeing but don’t worry about me - I’ve come across more than my share of keyboard warriors.

I only get wound up by things people say on the internet when I believe they are misleading - or downright shite.

It’s your site so you can pretty much say what you like, but don’t get all pissy when someone disagrees - bud.
 
Lpgc said:
I haven't de-cored my cats yet, will be doing when I get a bit of time but I don't see it as quite the priority that most people seem to see it. On most cars the most likely reason for cat failure is incorrect fuel mixture (too rich) but on most cars the MIL light is far more likely to come on in the event of incorrect mixture. I know my lambda probes etc are working properly, checked the fuelling and it's OK, but I've seen a few Elgrands with duff lambda probes / duff MAFs that have caused incorrect mixture and the MIL hasn't been on. I can tell just by driving a car if cats are clogged and wouldn't tickle the throttle or drive far with clogged cats. Another test for clogged cats is if exhaust gasses seem to be hotter than usual and coming out more slowly and/or the engine doesn't draw as much vacuum as it should. Can't imagine having cats clogged enough to cause engine damage and not noticing it tbh. A properly installed and calibrated LPG install doesn't make cat failure more likely, most likely the opposite, but I have seen plenty LPG installs that are setup too rich (particularly under high engine load open loop fuelling conditions) that could make cat failure more likely.
Click to expand...

Would the change from the jap petrol grade to our uk spec have an impact on why so many uk owners seem to have the cat problem on cars that apparently have been fine in japan?

Disclaimer: Not looking to start an argument but i understand that you have obviously alot of knowledge on checking fueling etc with fitting the LPG kits.
 
I really don't understand people sometimes...

The facts have been stated, not opinions. The rear cats need to be removed to ensure the longevity of your E51 engine.

Not all engines will fail, it's not a certainty but there are many cases of recorded engine failure directly linked to the blockage of rear cats.

In the end its up to you as an individual to make the choice based on the facts presented to you.

If you choose to ignore the advice then so be it, good luck.

If you choose to follow the advice, congratulations and enjoy many miles of happy motoring.

It's as simple as that!
 
It's like the smoking and lung cancer thing, everyone knows someone whos uncles, brothers, dog smoked 30 a day until they died in their 90s, but reality is for most it won't turn out so good.
 
Exactly!
 
DAMEscort said:
Would the change from the jap petrol grade to our uk spec have an impact on why so many uk owners seem to have the cat problem on cars that apparently have been fine in japan?

Disclaimer: Not looking to start an argument but i understand that you have obviously alot of knowledge on checking fueling etc with fitting the LPG kits.
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As far as I know the cat recalls were for cars running on Jap petrol anyway... and we don't have data on numbers of cat problems in the UK versus numbers of cat problems in Japan. I can only check/ensure that air fuel mixture is correct, not a chemist who can compare petrol, but it's probably safe to assume there are all sorts of nasties/contaminants in all sorts of petrol and I doubt different petrol will make much difference to the cat problem.

I didn't realise there was an argument brewing here and I hope I haven't said anything to make argument worse.. What I was getting at is that I don't see how cars go from being just fine to having blown engines so quickly. People fit wider exhausts to reduce exhaust back pressure and get a bit more power at high rpm, a blocked cat has the opposite effect and should very much restrict engine response, at which point would think the driver would know something was wrong before the engine was damaged.
 
Chris T said:
It's like the smoking and lung cancer thing, everyone knows someone whos uncles, brothers, dog smoked 30 a day until they died in their 90s, but reality is for most it won't turn out so good.
Click to expand...

Best analogy I've heard :joy:
 
Lpgc said:
a blocked cat has the opposite effect and should very much restrict engine response, at which point would think the driver would know something was wrong before the engine was damaged.
Click to expand...

The problem is that the blockage can build up over time, which will gradually reduce performance. It can also happen on one bank, rather than both. Or if a big enough chunk breaks off, the blockage can happen VERY suddenly.

I know of maybe 5/6 examples of people who have reported "loss of power" issues, struggling to get up hills, rough running etc. These have all had the rear cats inspected and found to be mostly blocked.

These are the people who come to the club with a problem, get an answer, and then piss off without giving updates... so I have no idea if those near misses caused long term problems, or the engines were fine and still going.
 
Karl said:
Best analogy I've heard :joy:
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Hehe... Missus' grandad smoked all his life and died of lung cancer at 95. I'm 47, just checking the forum while having a fag break lol.
 
Mine was definitely a rapid change:

E50ZRider said:
Hi Guys

03 E51 3.5

Start up drive etc. no problem

sometimes...usually later In day when engine is warm...I get a random problem

it starts and drives, but doesn't have kick down.

It is as if it has lost the top end, but the speed will still increase and no limits on revs...can drop to neutral; and free revving, but in gear seems to not drop the gear down.

any suggestions?

Peter
Click to expand...

I had my cat bypass pipes fitted and luckily it was saved...if id carried on it would have been lost engine I am certain
 
E50ZRider said:
Mine was definitely a rapid change:

I had my cat bypass pipes fitted and luckily it was saved...if id carried on it would have been lost engine I am certain
Click to expand...

So not everyone that had a near miss disappeared - my apologies @E50ZRider - I can't remember everything :joy:

But oh look, another example of blocked cats. But of course, this is just my opinion... obviously there are no facts behind this at all :rolleyes:
 
Karl said:
The problem is that the blockage can build up over time, which will gradually reduce performance. It can also happen on one bank, rather than both. Or if a big enough chunk breaks off, the blockage can happen VERY suddenly.

I know of maybe 5/6 examples of people who have reported "loss of power" issues, struggling to get up hills, rough running etc. These have all had the rear cats inspected and found to be mostly blocked.

These are the people who come to the club with a problem, get an answer, and then piss off without giving updates... so I have no idea if those near misses caused long term problems, or the engines were fine and still going.
Click to expand...

I agree and would also say there's the other way of looking at it.. Those people you advised had been noticing a problem with their cars for a while but at that point didn't know it was caused by the cats. They noticed a problem, came for advice and those that acted on advice likely prevented a blown engine.

Decoring rear cats is a sure fire way of preventing rear cat blockage and blown engines due to rear cat blockage / On the other hand for those that don't decore rear cats just being aware of the issue and what to expect if cats are getting blocked could also save a few engines. What we could say is it's strongly advised that rear cats should be decored but for those that don't decore rear cats if you notice a drop in power don't drive the car further until you've had the rear cats done. Whether someone decides to decore before any symptoms are noticed may depend on their confidence in noticing symptoms... I do intend to decore my cats, not because I might not notice the problem before I blew my engine but because the problem could occur at an inconvenient time - but because it'd only be to prevent a possible inconvenience it isn't high on my list of priorities at the moment.
 
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