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[Andy H]

OK reached the limit of my knowledge.

The usual question now is whether the MAF sensor, lambda sensor etc are genuine or pattern parts

[iainb]

My 2.5 has a simular problem and I found a small leak in the exhaust at the small box under the passinger side rear seat area, when I bodged it they problem corrected its self untill the the paste blew off a couple of days later

[TonyBrister]

I dont think they have ever been changed

[TonyBrister]

OK will check out the exhaust...

[Kevin Wood]

If it were overfuelling I would expect the Lambda reading to be low, TBH. Granted, it's after the cat but the cat would be flooded and not very effective if the mixture was too far out. As it is, Lambda is bang on.

What are the units of the HC reading? percent? If so, it is unbelieveably high, and this points to incomplete combustion, which doesn't tally with it running sweetly, and also being OK at idle. If it's in PPM (more usual IME) it's very low.

Other option is that the cat is knackered. Granted, it's just been replaced, but the CO is about what I'd expect from an ineffective cat. :-/

Grey smoke from the exhaust is odd as well. Real confusing set of symptoms. :-/

Would be good to get a Tech 2 on it and have a look at the live data.

Kevin

[Kevin Wood]

Hmm. Actually, air leak into the exhaust upstream of the Lambdas might do it. Don't suppose it's a manifold gasket or a leak through the SAI or EGR systems?

Kevin

[TonyBrister]

Thanks a lot lads... I'm taking all your thoughts to the garage today...I will keep you posted,,
Tony

[TonyBrister]

O.K. latest update...
The car has been round to  the main dealers and they can't find anything...
cylinder head off now as thoughts of valve problems but they are all seating ok...
But cylinder three isn't holding fluid so looks like a broken ring.. garage boss has very kindly said that they will do this but if it doesn't cure the problem he womt charge me for it...
watch this space.........

[Kevin Wood]

O.K. latest update...
The car has been round to  the main dealers and they can't find anything...
cylinder head off now as thoughts of valve problems but they are all seating ok...
But cylinder three isn't holding fluid so looks like a broken ring.. garage boss has very kindly said that they will do this but if it doesn't cure the problem he womt charge me for it...
watch this space.........

Blimey! Can't argue with that. A garage willing to take responsibility for their own diagnosis.

Fingers crossed.

Kevin

[TonyBrister]

I know it's a first for me too.
I had a new ecu fitted by a main dealer to solve a warm start problem... it turned out to be the cam sensor.
Fortunately I had purchased a warenty with the car and they paid for it even though it didn't need it (but I didn't tell them that!) 

[mark.adams]

I'm watching this very closely as i have the very same emissions problem right now....
I have new exhaust (from cat back) and new lambda sensor in position 1 and mine fails emissions on petrol and LPG, and the LPG is a mixer system not SGI.

[TonyBrister]

O.K. latest episode...
Injectors away for testing... Nothing realy wrong so having a clean...
In the mean time a hairline crack has been spoted in the exhaust manifold, this has been taken away to be brazed....
All should be back together on Wednesday so fingers crossed.
Looks like it could be air getting into the exhaust .....

[mark.adams]

I have one of those cracks in the manifold too, i wonder if it's that...

[TonyBrister]

O.K.  all done and back together....
Gues what... no change.
Where do we go now

[mark.adams]

How is the flexi joint by the cat?? Mine appears a bit frayed so i am wondering if i have a leak there