Smoke when warm

[ArmzFR150]

Had 2 other mechanics who have had a bit more dealings with PD engines look at it quick and neither know what's up with it. Tonnes of white smoke but not filling up oil with diesel or using oil, not loosing water or pressurising coolant and injectors appear within spec on data list....

Our diag computer and a mates garage one both read Injection volume, (even idling regulation) as It called it for each cylinder and I was told by a diesel specialist who knows his stuff that the ECU can only see plus or minus 2mg/h of adjustment. If it goes past 2 the injectors are dud.

At idle or fast idle cylinder 2 and 3 were both prettying at 0 fluctuating only very slightly but both tending to be more in the - than +

Cylinder 1 sat around -0.5mg/h at idle and -1mg/h at fast idle,

Cylinder 4 was the odd one out and sat at about +0.80mg/h at idle and around +1.0mg/h at fast idle.

Still none are close to +2 or -2.


Thinking I'm just gonna end up giving it to a diesel specialist to diagnose the fault. This annoys the hell out of me as if it were a common rail engine is know exactly what's what and sort it myself.

 

[Adam4D]

Video of smoke?

Had this before on a 3ltr Q7 which was injector seals on number 5 injector but you could see it via injector idle balance.

 

[Dan FR]

What does the smoke smell of?
Have you pulled the downpipe off the turbo? i suspect you will find oil in there and in the exhaust side of the turbo

 

[ArmzFR150]

I had the down pipe off about 4 days ago when I mr muscled the turbo and only soot in there no oil.

Smoke stinks like overfueling or unburned diesel and you can see the particles wafting about in the smoke.

Unless you've been Kaining the arse off it then you get a few puffs of blue. Not enough for the oil to drop noticeably considering I've recently done a 600mile trip.

No 4 injector is the only one with a positive correction would it point to this?

I'm beginning to suspect injector seals too.

On a CR engine I'd just change them to eliminate it but on one of these I know the bolts are all stretch so there's the cost of those as well.
I've been told when they go the injectors eat into the head where they move about.

 

[ArmzFR150]

Also I wouldn't be surprised if the turbo is on its way out as it's had overboost issues since I've had it but it doesn't cause overfueling or white smoke.

 

[Dan FR]

Ah, now that you've clarified... (I did skim over it all...)

If its un burnt diesel, and as the injector balance is within range, i would be inclined to look at the injector seals first...

If you can do the work yourself then cost won't be too great

 

[ArmzFR150]

I can do anything just need to know how lol. I know about the 12 stretch bolts that need replacing, obviously the seals in the bottom. Injector loom is common,
Are there seals where the fuel from the head goes into the injectors as well? If so they will also need replacing I presume.

Once replaced anyone know the torque settings for everything? And do I then new to completely set up the cam with a DTI gauge or can it be put back as it was if I don't touch the adjustment?

 

[Dan FR]

Never changed them myself - lots of info online - some useful info here: http://forums.tdiclub.com/showthread.php?t=282013

 

[Adam4D]

You can get away with not touching the adjustment, it's not good practice to tho as may mess with injector idle balance

Lots of info on the web about changing them, you can buy seal kits from united diesels as that's where I get mine from.

 

[ArmzFR150]

Right may be getting somewhere now.

Removed the rocker cover today and thoroughly inspected. No signs of injector movement or lift or diesel leakage or chuffing etc.
Injector bolts are nice and tight accross.

However upon very close inspection of the camshaft the ends of the lobes are slightly warn and the edges of the ends of the lobes are quite sharp to the touch.

One or 2 of them are slightly scorn up as well.
On most engines you wouldn't say any of it is excessive but after some research online it's very similar to pictures of other peoples "bad" camshafts.

I've got a guy who apparently knows PD engines well coming to look at it with me in the morning hopefully he can say for sure if it's excessive enough to cause the valves to not open for long enough and cause the white smoke from too much fuel not enough air etc.

The occasional blue smoke may be from the ageing turbo and be unrelated.

Or he might say it's not that bad and I'm back to square one again.... It's very hard to take pictures of the wear.

 

[Adam4D]

When my old cam had started wearing away, I had lost just over 1mm lift when compared to the new cam

If you have a good cam it should have chamfered edges on the lobes all the way round. Also gives you a good idea of how worn the cam is.

Smoke could even be valve stem seals

Lots of causes your choice which you start at

 

[ArmzFR150]

All I can think of is if it lost lift then presume that both valves wouldn't open as far causing lack I air in and out at idle till it's boosted resulting in smoke from unburned diesel?

 

[ArmzFR150]

Right we ripped it all apart this morning and I know exactly what the problem is.

In short the injectors have been moving around in the head wearing grooves into it where the diesel enters the injectors from the head.

The smoke is caused from the injectors no longer sealing against the now grooved head and the diesel runs down past the injectors directly into the cylinders.

It's done this rather than full up the oil with diesel like most end up doing.

He also explained the reason these engines suffer camshaft wear is because they often get a very fine must of diesel sprayed onto them from leaky injector seals causing excessive wear.


So new head and cam and injector seals head gasket and bolts.

Yay......

 

[gavin.garner.12]

Before spending money on it i'd start off with a comp test personally

 

[gavin.garner.12]

Oopps bit late with my last post, good to hear u found the problem