Hi all, it's been a while since I've posted but this one is doing my nut.

 

Bought this Octavia estate 2.0 TDI BKD L&K from an old lady a few years ago. It's a 2005 and only had 21k miles. It's now on 53k miles. It's had 3 services and a cambelt change in my ownership. 

I did the full service with all filters and timing belt was at approx 40k miles.

 

I have a few things going on which have kind of developed in a short period of time of each other.

 

Firstly. Last MOT, August 2023.

The tester was doing emissions and I could hear a loud blowoff sound after each acceleration. I'm an ex MOT tester and never noticed this on 2.0 tdi's before but can't really hear it very well in the car. Also, it only just got through on the emissions as it was black smoking a little.

 

Since then the smoking has got worse and if anything I think the power has increases 🤷🏼

Then came the rough idle. But again, still running sweet.

 

I've only recently started looking into the issue ready for next MOT.

I've done some data logging with ODBeleven and I've found the peak specified boost is 2300mb but actual peaks at 2600mb! Everytime on wide open throttle.

 

I've read that 2600mbar is the maximum the ECU or map sensor can read so it's likely the actual value is greater than 2600mbar.

 

Initially I thought sticking vnt but I've checked and the actuator rod seems to move ok indicating the veins are not seized. 

I've removed the egr and shudder valve and gave them a good clean.

I've then done basic setting reset on egr, fuel, and boost control but still the same.

 

The torsion value is bang on 0.0 and drops to -0.5 with a quick review so all ok there. 

The 

 

I do have the typical siren sound which actually also kicks in when carrying out activation tests on egr at idle or low rev.

 

Finally, I have some readings taken at idle and engine up to temp.

 

the fuel deviation values for idle are as follows

Inj 1, -0.66

Inj 2, 0.19

Inj 3, -0.14

Inj 4, 0.61

Inj quantity 3.84 mg/h

Fuel temp (G81) 80.1°c

Coolant temp G62 88.2°c

Boost pressure requested 1020mbar

Boost pressure actual 1040mbar

Ambient air temp 17.4°c

Intake air temp 37.8°c

 

I believe a deviation of +/-0.5 is tolerable but I'm not sure of what value 🤦

 

Now, with all of the above in mind I'm thinking down the lines of the N18/N75 valve block ,part number 6Q0906625 as this controls turbo and egr but it's a wild guess based on absolutely nothing 🤣

 

Any help or advice greatly appreciated 

 

Thanks in advance

Update so far

 

I've purchased a vacuum tester and confirmed there's no vac leaks, the pump is producing 28 inHg and the combo vacuum block unit is functioning correctly having carried out outputs tests and confirming with vac guage.

 

I have found the turbo actuator is sticking so looking like I have a sticking vein issue causing the overboost so I'll deal with that soon.

The turbo does produce the police siren noise so unsure weather to just bite the bullet and either recon this turbo as it's a low mileage turbo or replace with aftermarket new . . .or just give a go of Mr muscle or the revive turbo cleaner which seems to help with sticking VNT's

Unsure here so let me know your thoughts

 

Non the wiser on the fueling side but I've tripped checked the timing and although the torsion value is reading 0.0 the exhaust cam was about half a tooth out. Not had chance to do a good run yet so not sure if the lumpy idle or smoking has changed any.

 

And finally to add, the alternator overrun pulley is about to give up. So hopefully I'll be sorting that today and will give a better update of how it's running and idling.

 

Still very open to any comments.

 

T.I.A

the bkd turbos from stock go around 120,000 miles, the siren is the turbos last cries, replace the turbo whilst you have a choice. I have the exact car and i waited to find it, but i was duped the car had blag MOT's and the underneath is getting redone, i thought i had time, but turbo failed before i got round to it, if you can, recon your turbo and get hybridised, should last alot longer. works out cheaper, but better  aswell for the car.

 

i hope this helps.

I have a BKD on 110 000 miles. Had the turbo replaced at 30k Miles under warranty thank god at main dealers. That was 2009 and cost £1200!

What mpg  are you getting? Actual via filled tank etc not the onboard display which is vastly over optimistic.  I get from 39 mostly urban to 63 on long M-way journeys.  Which I think shows a fairly healthy engine.

32 minutes ago, Golf-Fiend said:

I have a BKD on 110 000 miles. Had the turbo replaced at 30k Miles under warranty thank god at main dealers. That was 2009 and cost £1200!

What mpg  are you getting? Actual via filled tank etc not the onboard display which is vastly over optimistic.  I get from 39 mostly urban to 63 on long M-way journeys.  Which I think shows a fairly healthy engine.

Thanks for your response. I typically get 40mpg urban and approx 50-55 on a run 

well half a tank in my golf which had egr taken off and dpf, local mileage i get was 300miles ish, not motorway, my octavia before i cleaned egr a asv was 215 miles half tank, after clean was near 240 ish miles, the EGR & DPF really do harm, without EGR my golf seems quieter, more responsive too and that still has original turbo at 173,000 miles on the clock.

Had the same problem with my BXE but it was the actuator that was sticking causing overboost and random limp mode. Turbo made a high pitched whine/whistle etc but disapeared once the actuator was freed up. I sprayed all I could with wd40 and manually operated it back and forward until it moved smoothly. 

I had over boost on my BKD from when I got it at about 70k miles. The Mr muscle trick usually sorted it out for about 9 months, but eventually it stopped doing anything and I re-cored the turbo smack on 100k.

 

The fins had sheared off the turbine and chewed up the vnt mechanism so it was sticking. Mellett core and a new vnt ring sorted it out.

mr muscle is bad, it corodes the metal, i would advise never do that, a good solvent designed for engines work, egr, dpfs kill engines.

I readf that Mr Muscle is death to alloy. I was going to try it but was worried I would damage alloy parts on turbo. Think the best option would be to either strip down and clean and recondition yourself or replace with new or good second hand turbo. I was lucky as it was the actuator itself that was ssticcking,

who ever got people started on drain cleaner on an alloy needs dealing with, these alloys go porous and start degrading after that treatment, best to take out and hand clean, carbon and grime build up and most people seek the easy fix.

 

rant over, sorry

 

Just to update on my original post and the update post above.

 

Ive replaced the alternator pulley, that's that sorted.

I did the revive turbo cleaner.

Worked well. I've not had the overboost fault return and it's been a good 3 to 4 months and 4'000 miles. Lumpy idle has also gone.

 

I still get black smoke on full acceleration although maybe a little less. Turbo still make sure noise although not as bad. Passed recent MOT so smoke not bad enough to fail but is mostly noticeable at night in headlights of the car behind.

 

Service is now due so plan to give it a full service and another revive clean and see how it goes from there.

If its still making black smoke try a bottle or too of injector cleaner in the fuel and perhaps replace air filter. My old octavia exhaust was a bit black and sooty but I used Forte diesel injector cleaner that I got from my old mate at his garage. Took a couple of tank fulls but cleaned it up. 

Alasdair

Just now, Alasdair1 said:

If its still making black smoke try a bottle or too of injector cleaner in the fuel and perhaps replace air filter. My old octavia exhaust was a bit black and sooty but I used Forte diesel injector cleaner that I got from my old mate at his garage. Took a couple of tank fulls but cleaned it up. 

Alasdair

I've been using jet premium diesel for the past 2,000 miles or so.

I've used serval different fuel cleaners initially which didn't seem to make much difference. I did however notice an increase in throttle response after the revive turbo cleaner.

Still, I will use some more diesel cleaner along with the service 👍

I did use redex and wyns but they didn't make much difference. The Forte one was more expensive but got good reviews and it worked. Good tip in puting a tank of premium diesel in from time to time. My local garage has a pump now so may give it a try. I never thought of that I assumed it was for performance diesels.

Alasdair

Glad to hear the BKD has improved.  Mine smokes under hard acceleration but it has since I got it at 26k miles. It's only the first couple of times. After that it's Clean. I try to do this as often as possible when on dual carriageways etc.

I get slightly better pence/mile using Supreme Diesel. Very similar.  My worst pence/mile is using standard diesel according to my Drivvo app. It cheaper than buying expensive additives.