Valve Timing - PD170 vRS

[max69vk]

Normal Torsion value should be 0.0-0.5 on these engines.

The injector deviation looks well within limits (I believe 2.99 indicates a fault) although as close to 0 across all 4 is the ideal. Also if the timing is out then these measurements will also be out as the ECU is attempting to balance the fueling to smooth the engine.

My car came back out of the garage for the 4th time on Saturday, they apparently found nothing in over 100 miles of road testing, yet 10 miles down the road the DPF is back on & after checking the oil level its overflowing again! I'm dealing with Audi UK now as the 'master' techs at the garage are clueless. I've logged loads of technical info off VCDS & it looks like turbo & DPF are shot, on top of the entire top end they previously replaced FOC. I'd get on to SKODA UK & kick up big time.

*Edit - Ignore my comment above about 2.99 indicating a fault, I've since been informed that this is actually a failure & that +0.50 deviation can indicate an fault*

Edited 23 May, 2012 by max69vk

[max69vk]

Hi Nick, hope you're having some more luck with getting your car sorted? Sounds like you & I are in exactly the same boat here so I thought I'd give you an update on what is going at my end & hopefully between the 2 of us we can get our cars fixed!...

To be 100% clear on this, my car still does not run right & sounds terrible. The top end still sounds unbelievably rattley, especially under light throttle, the oil is still overfilled & apparently contaminated (I was told it had been changed & even had the book stamped by the garage). When driving the car last night I've noticed that to be able to pull away without stalling the engine or it spluttering it needs to be revved to around 1500rpm, where-as before I could easily pull away on engine tick-over (820rpm), yet another confirmation that the car has lost power.

Here's the kicker... Scanning the car with VCDS brings up no fault codes

More VCDS logging & got the results below, looks like cylinder 3 has an issue now! The car has previously been back & the whole top end was replaced due to a leak discovered on cylinder 4 which meant the injector wasnt sealing & was leaking diesel into the oil (& vice versa). Also noticed that they've managed to throw the cam timing out even further since fitting the new head & cambelt (shows as tosion value on the new readings & steering angle on the old)!

Looking again at the injector deviation readings you posted above, cylinder 1 looks to be the issue, whether it be a leaking injector or damaged head it's not right at all.

My latest readings (cyl 3 being compensated by all the other cylinders)

My previous readings when cyl 4 was found to be leaking (group 013 bottom row)

[Nick P]

That makes for depressing reading Max.

Between discovering the problem after getting the injector recall done and giving it back to the dealer for 3 weeks to attempt to fix I scanned it and the values were slightly different then:

Torsion value was -1.84, same as now.

Stabilisation values right after startup (with a second or so of rough running):

After running for three minutes or so:

So after they said they replaced all four injectors again, I now have those figures of about 0.96 -0.42 -0.53 0. Like you I have no fault codes.

I just wish I'd had the presence of mind to take some logs before I took it in for the recall. I hate that I was pressured into getting the recall work done. This car was perfect and I loved it before they got their hands on it.

[Nick P]

I'm not sure how the timing would be affected by the recall work. Presumably they only need to remove the rocker arm to access the injectors - not disturb either the inlet or exhaust camshaft?

http://www.volkspage.net/technik/ssp/ssp/SSP_316.pdf

http://ovh.jazdw.net/SSP_368_The_2_0l_-_125_kW-TDI_Engine_with_4-valve_technology.pdf

[max69vk]

I hate that I was pressured into getting the recall work done. This car was perfect and I loved it before they got their hands on it.

I feel your pain on that one.

In answer to your question, the timing can be affected if the rocker assembly &/or injectors aren't fitted back correctly, the pressure that these units operate under is so great it has been found that it can actually lift the rocker assembly ever so slightly (if not tightened down correctly), in this case who's to say the rocker assembly wasn't just bolted back on without being adjusted to work with the new injectors (VAG themselves have revised the fitting instructions for rocker 'clearances' at least once before) so something wasn't right first time round.

The injectors & rocker assembly are also meant to be secured with 'single use' stretch bolts, whether this is done or not is another matter entirely & I've never seen them listed on any of the report printouts I've been given of what’s been changed, & they've listed every other component (big or small) used.

In my case I've only had my cambelt changed as a precautionary measure to prove that an 'older' cambelt had no influence on how the car was running following the recall work, so basically it’s another thing to cross off the list of potential causes despite how injection timing affects the running of the engine. Really it’s also proved that the 'Master-techs' working on the car weren't checking their work as they knew the measurement was out before they started, & was then even further out after they finished when it was given back to me.

Some interesting reading here regarding Inj timing.... http://www.myturbodiesel.com/1000q/multi/PD-adjust-Idle-TDI.htm

And some good info from here from VAG themselves on the PD injector unit, which goes someway to show that how whilst the ECU controls the injection (from the crank sensor) how the cam can affect the injector timing (especially the ‘pilot’ phase from my investigations)... http://www.volkspage.net/technik/ssp/ssp/SSP_352.pdf

I'm now at a stage where I refuse to take the car back to the original garage (4 times is enough) or even communicate with them. AUDI UK have said themselves that they completely understand this & are now directing the car to a different dealership (same group however) as they want a fresh set of mechanics to look at it following all of the technical details I've provided from VCDS. Unfortunately I'm pretty sure I now have to make a claim through the small claims court to try & get back some of the £800+ spent on buying diagnostic equipment & having unnecessary work done on the car just to prove that it was the work they did they caused all of the issues, it just feels never ending :(

[Nick P]

Just tried logging again with the car warm after driving to work.

Values more like

0.49 -0.26 -0.36 0.13

Torsion at -2.63 though!

Car started fine for a change this morning - not a grumble. It occurs to me that the only difference is with the hot weather I've started using A/C - the car was started with Econ mode on the climatronic turned OFF. Every other time Econ has been ON.

[max69vk]

Cylinder 1 still looks a bit suspect to me, do you know if they've compression & leak tested the cylinders? As for the Torsion value, now I'm confused! The AC runs off a seperate belt so I've no idea how that could influence the torsion?!

With the starting issue improved how was the general running of the engine? Did it still sound really rattley?

[Nick P]

So with regard to my theory about my problem being alleviated by having the air-con on - this idea is still holding up.

I just tried logging whilst alternating between air con off (pressing the econ button) and having the air con on full blast. I observed that with the air con off the car was injecting 4.5-5mg per stroke over ~3.5°KW specified duration. With the air con on full blast the car was injecting 7.5-8mg per stroke over more like 4.5°KW.

Now recall I said my bad idle can be fixed with a tiny blip of the throttle. I think the figures above show that running the air con is effectively doing the same thing.

[silver1011]

Has your dealer agreed that there is a problem with your car Nick, are they going to take a look at it?

[Nick P]

After having it for 4 days, then 3 weeks and apparently changing all 4 injectors and seals again, they conceded that it probably still wasn't right, but there was nothing more they can think of to do with it. They were able to reliably reproduce the problem with it parked on an incline in their car park.

When it was in for the 3 week stint I explained the large idle stabilisation trim values and the service manager said their technician had observed this too. At that point I hadn't noticed the torsion value and I still haven't re-engaged with them to challenge them about it - I've just been too busy.

[silver1011]

Hmmm, my dealer pretty much said the same.

We can see the issue. Replacing/adjusting A, B & C hasn't cured it. There is no D.

Nothing more we can do.

Luckily mine seems to be behaving of late, however I won't really know for sure until later in the year when temperatures start to drop.

Keep persisting, someone will eventually suss this out!

[Nick P]

Pure conjecture, but I wonder if the people who have had DPF problems since the recall have had their timing advanced, causing the secondary injection phase to occur too early to generate high enough EGT?

[Nick P]

http://www.audi-spor...tor-recall.html

http://www.audi-sport.net/vb/a3-s3-sportback-8p-chassis/155474-2-0-tdi-bnm-engine-sounding-rough-after-injector-swap.html

[max69vk]

Any progress with this? I've got my car back after the 2nd garage drained about .75 litres of overfilled oil the DPF seems to be behaving itself, the car is still gutless below 2000rpm, & the kick above is somewhat lacking still. I specifically asked them to check the timing & they've said its spot on when using their tools... Not very reassuring considering how well documented the timing issue is, this points to an issue with the manufacturing & use of their own tooling to do the job which appears to give a very wide variance when they change the belt.

With regards to the lumpy I used VCDS adaption to tweak the idle rpm till I found its sweet spot, which more me meant dropping it from value 128 to 100 (approx 810 rpm to 790rpm).

[Rupedog]

HI All - just reading this old thread after a search for cam timing (torsion) adjustment after cam belt replacement due to poor fuel economy.

For info I had the injector recall (170 tdi 2.0, BRD, Audi A4) and after had running issues and oil in the fuel. Reading many similar threads, including where a technician posts, his statement was on this engine, oil and fuel mixing was always leaking injector seals/poorly seated injectors. One case was the holes in the head had become ovaled. The only other possible cause of this is the tandem pump, but the tech said this engine (later tandem pump) has never had TP issues. Its always bad sealing/seating after the injector recall.

Main dealer did not really want to know, checked diagnostics and said no leaks and to speak to Audi UK if I still had an issue. So I did. Audi UK initially said 'poor workmanship' I would have to go back to the dealer, not AUK issue - and they have not had any other issues reported after the injector recall, which a quick Google will reveal is complete BS - clearly LOTS of people have this exact issue. So I lost it a bit (politely!) and they assigned someone from customer complaints to it. They got the dealer to (very reluctantly) replace the injector seals (not injectors, just the 2 'o' rings on each. It is crucial they are fitted correct way round.

Unfortunately there is NO way to identify poor sealing/seating so you have to remove the injectors and re do it - and take extreme care and make sure the holes/seals are spotlessly clean. The slightest contamination can cause the seal to leak a little.

Anyway, seems immediately better after it was done. Early days, but believe it has cured the issue, keeping everything crossed but so far so good.

Key info is the ONLY way oil and fuel mix in this engine type is by passing the injector seals (due to damage, contamination or poor seating) or the tandem pump - and its apparently never this! - but a cheap easy to replace part, so you could try replacing this to eliminate it).

So now, I just need to sort why after the cam-belt replacement the fuel economy dropped 20% - and it cant be the belt off by a tooth as I would have a wrecked engine by now, so the consensus is the 3 degrees +/- adjustment on the Torsion value, which also effects starting and idle (but NOT fuel/oil mixing!). Mine starts lovely, even in the cold it starts instantly, half a turn! But fuel econ on a long motorway trip is down from 50-52mpg avg to 43-46 mpg. Not sure whether I need to retard or advance to get this back to where it was pre cam belt change. As the 'Independent' VW group specialist in Chandlers ford Southampton did not even put the bumper back right, then I wont have them touch it again.

[silver1011]

Are you manually calculating the mpg or relying on the OBC?

After I had the timing altered I too thought my mpg had plummeted, however my manual calculations revealed it was the same.

For some reason the OBC now reads around 6-8 mpg lower than it used to.