L322 2006 4.4 AJV8 Emmissions fail

[Wazzajnr]

OK, so as per the title, failed mot on Emmissions today.
HC was a pass but CO was up around 0.45
I've had a recurring fault of "Bank too lean" over the last few months but only throws it a couple of minutes after starting from warm. If I set off from cold with fault cleared it will run all day without the fault coming up.
Seems to be bank 2 more often than bank 1 but Definately happens on both.
Again, if I clear the fault once running it will drive all day without coming back.
I also sometimes get fuel trim errors at the same time but looking on live values, the trims and probe readings look reasonable (bank 2 tends to read marginally higher but follows bank 1)
Do any of you ladies and gents have any suggestions?
Thanks in advance.
Paul

 

[Grrrrrr]

First thought was o2 sensors. Second thought was a leak either in exhaust or inlet manifold.

On the s-type the windscreen jets leak right onto the plugs causing the cop leads to deteriorate. Nothing like that? Guess that would misfire and run rich though.

 

[Wazzajnr]

I've got a set of plugs coming.
What I can't understand is that all the faults I've had say bank too lean yet the Emmissions seem to suggest it's too rich.
I really could do with another one to compare traces with on the sensors!

 

[Grrrrrr]

If you put your hand on the engine while running and feel the beat is there an intermittent skip?

 

[Datatek]

Ah the joys of Henry's favorite V8

 

[DanClarke]

NOT an L322, but my P38....so probably not relevant but....
Every time I had "missing" and rich running (stank of rotten eggs out my back-end ) it was an HT lead gone bad or a failing coil-pack.
You only noticed the "missing" at stationary/crawl speeds, once doing higher MPH you could not feel it.
Garage changed them 1 at a time each time, then another one would go some months later.
In the end I had all leads and both packs changed at the same time. No more problems.

 

[Wazzajnr]

If you put your hand on the engine while running and feel the beat is there an intermittent skip?

When idling, you can feel a very slight un-eveness to it which is why my first port of call is a set of plugs. That said, they're not easy to come by!!
I've ordered a service kit from Island.

NOT an L322, but my P38....so probably not relevant but....
Every time I had "missing" and rich running (stank of rotten eggs out my back-end ) it was an HT lead gone bad or a failing coil-pack.
You only noticed the "missing" at stationary/crawl speeds, once doing higher MPH you could not feel it.
Garage changed them 1 at a time each time, then another one would go some months later.
In the end I had all leads and both packs changed at the same time. No more problems.

The coils on the AJV8 are coil on plug type and not cheap although i would expect them to throw a fault if there was anything wrong with them. I only really get a misfire when cold occasionally and it can be any cylinder. Once i've pulled the plugs i should be able to see if any look in bad nick.

Ah the joys of Henry's favorite V8

I still wouldn't swap it for any other engine. This car has been badly looked after for several years (Hence getting it for a song) but still runs pretty well. Yes the emissions are a bit high but it will be maybe one or two things. Worst case scenario is the cats have failed which will cost me over 1500 quid but the car as a whole is still reasonable at that price.

 

[tarphenry]

On my old 3.9 v8, I had the slightest hesitation on tickover,car ran fine and 3 garages couldn`t find anthing wrong. I finally traced it to the valley gasket failure ,it was allowing the tiniest drop of water into the inlet tract and causing 1 cylinder to hic, every so often. dont know if it would apply to your v8

 

[Wazzajnr]

On my old 3.9 v8, I had the slightest hesitation on tickover,car ran fine and 3 garages couldn`t find anthing wrong. I finally traced it to the valley gasket failure ,it was allowing the tiniest drop of water into the inlet tract and causing 1 cylinder to hic, every so often. dont know if it would apply to your v8

Thanks, I don't think it's that on mine, I think it has been letting air in after the MAF.
I'll know on Monday once I get my new plugs and rebuild it.

 

[Wazzajnr]

Oh Bu*(%r, still running madly rich on bank 1 i think.
I was really hoping that sorting out air leaks on the inlet tract might have sorted it but it appears not.
Trouble is, i don't know what readings i should be getting from the O2 sensors as they're wideband. I do know that the "Equivalence ratio" is reading 1.000 (Varying by +/- 0.003 constantly but average is 1)
The trims were miles out but after a while of idling, bank 2 was around 4%LTFT and around zero on STFT. Bank 1 was still at over 10% with STFT at around -5%

Maybe i need to let it run longer for the trims to stabilise but it still smells rich and there is clearly a difference between the two banks.

Time for some more googling i think unless anyone has any further ideas???

 

[Wazzajnr]

And the rhs cat has disintegrated by the sound of it.
£1k per side! What is it effin made of!?!

 

[Datatek]

And the rhs cat has disintegrated by the sound of it.
£1k per side! What is it effin made of!?!

Platinum.

 

[Wazzajnr]

Platinum.

Yes, as are the cats that I fitted to the p38 at 130 quid a side.
I've bought many cats over the years and never paid more than a couple of hundred.

 

[myfirstl322]

Yes, as are the cats that I fitted to the p38 at 130 quid a side.
I've bought many cats over the years and never paid more than a couple of hundred.

If it were me I'd be either taking a gamble and buying genuine used or buy a quality aftermarket 'universal' and get welding.

 

[Wazzajnr]

If it were me I'd be either taking a gamble and buying genuine used or buy a quality aftermarket 'universal' and get welding.

Yes, I've found that magnaflow in USA make replacements 500 dollars or a universal one for 180 dollars.
To be honest, if I can get both sides ready made for under a grand, I'll take it!
I've emailed their UK stockist so hopefully get an answer tomorrow.

 

[Wazzajnr]

OK, 495 per side for made to measure cats with 3 week delivery time.
300 quid for two universal ones delivered in a couple of days so I think that's what I'll do.
Still got a leak somewhere near egr valve and trims on bank 1 are a mile out.
I was assuming that bank 1 was lhs as viewed from driving seat but its rhs bank that the cat is dead on.
I would have thought that the air leak at the egr would affect trims on both sides. If so, why are they so different? Unless I've got the banks mixed up.
Going to pull the 02 sensors tomorrow and stick the endoscope in the rhs exhaust to see if the cat material has vanished completely.
If I can get some decent pics I'll post them up.

 

[myfirstl322]

OK, 495 per side for made to measure cats with 3 week delivery time.
300 quid for two universal ones delivered in a couple of days so I think that's what I'll do.
Still got a leak somewhere near egr valve and trims on bank 1 are a mile out.
I was assuming that bank 1 was lhs as viewed from driving seat but its rhs bank that the cat is dead on.
I would have thought that the air leak at the egr would affect trims on both sides. If so, why are they so different? Unless I've got the banks mixed up.
Going to pull the 02 sensors tomorrow and stick the endoscope in the rhs exhaust to see if the cat material has vanished completely.
If I can get some decent pics I'll post them up.

Lot of money but what can you do?

I seen a utube vid recently of a couple of likely lads cashing/weighing in their stash of cats, I was very surprised at the prices paid out, ie. an A8 V8 cat was something like £150!! That's 300 squid a pair ffs...and something like £50 for a piddly Fiesta.

 

[Wazzajnr]

The last two I fitted on the p38 were around 130 quid a side I think.
That's fine, if they were 250 a side, I wouldn't bat an eylid, I'd just buy them. But, I'm sorry, 675+vat a side from Island is the cheapest around and I simply ain't paying that.
I can't believe none of the pattern makers make these. You can get aftermarket cats for virtually any other car. It's not like there aren't many on the road!
Anyway, I'll get pics as I go along and hopefully it will help others in future.

 

[Wazzajnr]

OK, update. Di a lot of testing today and upshot is that I think the duff cat is throwing all the readings out.
Apparently, the ecu can use the post cat O2 sensors to adjust mixture as well as the pre cat and they can "fight" each other.
New universal cats arrived today, 220 quid for the pair.
Got old ones off but two studs snapped on drivers side so I'll be under there with stud extractors tomorrow.
The drivers side cat is indeed empty. I put the endoscope in there but couldn't get it to take pics.
Did get pics of the downstream sensors though and they definitely look different in colour so I guess the lhs cat was working to some degree.
New maf and wideband sensors arrive tomorrow and downpipes going to fab shop to be cut and shut.
Hopefully, once I get it all back together it will pass the mot!

 

[Wazzajnr]

Where on earth do they get these bolts from?!?!?!?!? I've seen melted cheese with more durability!!!!
2 exhaust manifold to downpipe studs.
I've welded nuts to both of them twice and slightest touch and they just shear off again.
No thread left so only thing left is to chop them off and try the "Easy-Outs" on them.
Don't really want to drill them out as i'm not sure i can get in there with a tap to re-tap them.
Might end up with a bolt right through but getting on the back of it when tightening up will be fun........................NOT!!!!!