A4 2.0 TDI 2006, Misfire, Blow Back Noise, Lack of Power, Help please

Looks like I've just joined the BPW cab club with same problems stuck on a1 now gutted....
 
Yer it's excactly the same has your video mate, aa has been out said it could be timing out or a valve. I had the belt changed about 6 k back, so it can't be that the belts nice and tight etc. Just waiting for recovery then in morning il get the rocker off and investigate.
Its done 86k now is that about same has yours when it went? We all should defo complain to Audi because it's all BPW cabs what's doing it
 
I wouldn't believe the AA guy as they didn't know what was wrong with mine either, get the rocker cover off and drop me a line tomorrow if you need anything pm me. I have a parts list which may come in use.

Myself and Ron did try with Audi and had no luck whatsoever, I feel it is down to the fact that most cars suffering with this problem are out of warranty.
 
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I wouldn't believe the AA guy as they didn't know what was wrong with mine either, get the rocker cover off and drop me a line tomorrow if you need anything. I have a parts list which may come in use.

Myself and Ron did try with Audi and had no luck whatsoever, I feel it is down to the fact that most cars suffering with this problem are out of warranty.
Krumz, take your email out of your post and pm him instead.Youll be a massive spam target
 
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ok! update on my motor found the problem its the camshaft its burnt through 2 tappets and the others was on there way out. its generally i common fault with the gttdi golfs 150 they eat camshafts.... basically the mechcanic has said this generally only happens if you use the wrong oil. so if your using halfords special get it out i have used castrol edge 5w 30 since ive had it but obvouisly the prevouis owner may not have... all in its costing me a grand to fix thats including labour using genuine parts. so moral of the story buy cheap, buy twice or in this case buy cheap pay alot out!!!
 
ok! update on my motor found the problem its the camshaft its burnt through 2 tappets and the others was on there way out. its generally i common fault with the gttdi golfs 150 they eat camshafts.... basically the mechcanic has said this generally only happens if you use the wrong oil. so if your using halfords special get it out i have used castrol edge 5w 30 since ive had it but obvouisly the prevouis owner may not have... all in its costing me a grand to fix thats including labour using genuine parts. so moral of the story buy cheap, buy twice or in this case buy cheap pay alot out!!!

The cause of the failures is not the oil as my car had been serviced by dealers and following that I only used oil directly from VW. Apparently this is even different to the 5W - 30 Castrol although Castrol state their oil conforms to the 507 spec.
I also know of a number of VAG owner with the same problems who have a history of using good oil.
A number of ideas have been discussed but so far it still appears the original cams supplied by VW have not been hardened correctly.

Also have a look at the link below if you are interested

Camshaft lobe lifter wear on VW Audi TDI PD engine and replacement DIY

Make sure your mechanic carries out an engine flush and removes all the debris from the oil cam and tappets, even if that means removing the glow plugs and turning the engine over without the cam and hydraulic tappets to ensure the supply holes are clear.
 
The cause of the failures is not the oil as my car had been serviced by dealers

who are only interested in getting the car thru the warrenty period + 6 months........... any more than that simply isnt their concern.
why make a car last 300k miles without fault????? no-one would ever buy a new one!
im surprised audi even go to the expense of making their cars with six digit mileage counters anymore!!!

what sort of mileage/time gaps are there inbetween servicing? unless its 10k 12 months or less then servicing is to blame.
150bhp golfs have a more aggressive cam... coupled with the same bs "long life" servicing malarkie...... makes them even more prone to this.
 
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Right Gents,

Just to close the loop on this one, following changing the cam I was always getting a ticking noise when it was very hot or if I was driving it hard (even changed the oil to 5W40 fully)

After about 40 / 50 k miles of changing the camshaft I was getting a very rough idle, further investigation found there was an imbalance on MBV 13 (injected qty per stroke) between the cylinders (lowest value of -2.99mg/strk and highest of +2.99mg/strk).

So I proceeded to get some second hand injectors and play around with swapping them over, when swapping the injectors over, I found the injector lobes on the camshaft were stepped ! Again horrors of camshaft wear ! but this time the lobes for the valves were not worn !

Obviously the root cause is poor lubrication, but I had checked the oil pump and the pressure was withing spec, after stripping the top of the head off I found the cause of low oil pressure. The sealing plugs on the injector rockers !

When the injector rockers are manufactured, they are drilled axially to link the oilways, this holes is then plugged with Aluminum plugs, the plugs managed to migrate out axially and hence the loss of oil pressure to the camshaft, as this is downstream of the oil pressure switch, you do not see the oil warning light come on.

See pictures below, where there is a plug missing, one plug is almost out and where one is still intact, (obviously as soon as you loose one plug you have a leak path and the oil will take the easiest path)

Why? Well I put it down to differential thermal expansion of the two metals, as they expand at different rates, when the engine is either warming up or cooling down the plug to shaft clearance changes, with oil pressure working on the back of the plug, it naturally forces it outwards.

How to fix, get the right diameter silvesteel, squash it slightly, use some Loctite (check for right grade, oil and correct temperature) and just to be safe punch it once its in there. !
 

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Hi Ron,

It's a pity I didn't see your reply earlier !!

Today:

The compression tester arrived and I did a compression test,*
Cylinder 1: 500psi
Cylinder 2: 510psi
Cylinder 3: 500psi
Cylinder 4: 510psi

So all at around 35bar

I then moved onto removing the inlet manifold, disconnecting the injector wiring loom and turned the engine over, all the cylinders were sucking but no2 was puffing back as well as sucking.

Reconnected the injector loom and started her up, definitely could hear the blowing back and popping coming from no2. Also found that there was no carbon buildup on the inlet manifold and cylinder head ports on cylinder no 2. Indicating the blowback is burning off the **** in the inlet.

Took the front end off and checked the timing. All ok

So ended up doing what 2 AA technicians, 8 mechanics and 3 engineers said it was and removed the cylinder head (regardless off the compression test being ok)*

Unfortunately have found nothing, no cracked valves, valve seat is ok, piston is ok, head gasket and mating surface marks show no indications of passing, the only thing I found is there is no carbon buildup around the outer circle on cylinder 2 inlet valve, indicating the edges of this valve are getting hot.*

(yes should've believed the compression test)

The only thing I can think of now is one of the injectors is injecting diesel prematurely, causing the issue.*
Have you read the pd engine document on my original post?*

So for now I have to get the head skimmed and get the injector tested!!
(and buy lots of parts, might as well do the belt, water pump, tensioners etc)*

Ron: what is your engine code ? How many miles ? Can you get the Inlet manifold of and check which cylinder is blowing back ?and swap the injector over and see if the problem persists.

Where abouts are you in the uk ?*

Look forward to hearing back ...
Look at turbo possibility it's knackered???
 
I've got a similar sound happening to mine, a thudy blowback type noise on the air box/inlet.

It started happening as I was towing my caravan.

Waited till next morning to call breakdown and issue had gone ?! No noise, no misfire & full power back? Green Flag man cleared a MAF fault and I thought all was good.

Till today, after about two hours driving its stated again. Feels like a misfire, lacking in power. Metallic noise and an air inlet thuddy noise.

I need to tow my caravan back home to Leeds (from Birmingham) tomorrow and wonder if while it's making this noise I'll be causing damage?

Why would it come and go?

A4 cab 2.0tdi 137000 miles, 2007
 
Following up on this almost two years later, mine was the same, worn camshaft. Just over £1000 later (inc cambelt and water pump at the same time) I got it back. Ouch. Now done 153,000 miles and still going ok.
 
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