THE KICK INSIDE

v6 tdi....34k miles, main dealer 'serviced'

been fine, i topped the oil up last night a(1/4 ltr) and fueled it up, did 300 miles today, noticed this after about 200 .....

runs fine, goes ok..idles like massey furguson with a cough....bad enough you feel it...

just started doing it...droips down to idle its fine for a second or two then it starts lolloping off geting worse and worse..it does stabilise to a rough lollopy idle at about 800 rpm but its horrible!

if it was a v6 petrol i would say 2 or more plugs were oiled up.....

anyone got any ideas before i take to the dealers?
(not sure itf the fuel filter or air filter has been changed in the 2 services its had, looking at the pollen filter i swapped on Saturday i imagine NOT)

Taxi 219

I think fuel and air filter are at 40,000 miles,but i maybe wrong on the V6.

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Paul

rotodiesel

Air filter 20k miles on Superbs in most cases - see service book. Dealers don't usually bother and a blocked air filter really takes the edge off the running and will cause the turbocharger's compressor to pull oil into the inlet from the engine crankcase breather.

I would strongly recommend fitting a new fuel filter every 30k miles and to drain the water trap at every service (dealers don't do this either). I use a vac pump to prime the new filter - don't crank it to death.

rotodiesel.

THE KICK INSIDE

roto you seem to know what your talking about here....so i will pick your brains!

just been and had a 'firk' in the dark an all and the fuel filter looks original to me (so assume 3 1/2 years and 34k) and the air filter is filthy! (we had to hover the sand out of the bottom of the box and i was getting plumes of dust into the sky banging it against my hand!)

given the symptoms seem to be:-

1. slight decrease in economy (perhaps 5%)
2. still goes well enough (strong pull above about 1200 rpm)
3 below 1200 rpm seems ok unless it drops to idle fora couple of seconds in which case it runs really rough, the wife says 'sounds tractory' and it is rough getting progressively better until you get to 1200 rpm ish then its fine....

as you know i had the battery off at the weekend but driven it since without any probs, drove 130 miles this morning and it was fine....came home and noticed this pulling off the motorway after about 80 miles.....and now its doing it all the time.

Does this sound like air/fuel filter to you or something else (i know you aint seen or heard it but if you said 'could well be' i would try changing both, if you said 'nah...unlikely' then its straight to the dealers!)

rotodiesel

TKI, I can't really help much with the V6 diesel - it's not an engine which was suited to my job so I've made more of a study of the PD engines. The V6 uses an electronic version of the old Bosch VE rotary pump. Looking at the Bosch diagrams it seems that the speed signal is obtained externally to the pump. If it's anything like the PDs, there will be a speed probe on the engine block near the flywheel - I wonder if this was disturbed when the oil was changed?

Other than having a really good look around the engine bay to see if anything has been disturbed, it's probably time to get any codes read. A good independent Bosch diesel specialist will be a much better bet than a clueless VAG dealer.

You did tighten up the battery terminals properly I hope?

rotodiesel.

Basil

I notice that the local GM dealers suddenly become very capable of finding the slightest "fault" and suggesting a major repair as soon as the car is out of warranty.... eg - replacing a slightly cracked decorative plastic panel atop the engine that no-one is gonna see and has very little function...

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rotodiesel

That's nothing - Skoda UK tried the recall trick on mine as soon as the warranty ran out and it became apparent they would never see it again. In fact, the tandem pump recall was issued in '05 so they could and should have done it sooner.

PD engines can have either Bosch or LUK tandem pumps - it's the LUK ones that can leak. One minute with a torch and a mirror confirmed my car has a Bosch pump.

Skoda UK won't tell you that the Bosch pumps are OK (they perhaps think their customers are not bright enough to use the Internet - other countries such as Canada and Australia publish all the details including the rework instructions). Instead they seem determined to waste my time.

I wonder what else the dealer would have "found" (or broken) if I had taken the car in.

rotodiesel.

THE KICK INSIDE

been to the dealer, drank as much of their 'free' coffee as i could....they wired it up to life support....

then came backand said 'computer says nowt wrong, no codes...." £40 please

well to be fair they said 'we will need it in for further mechanical investigation'

to which i replied 'what will you be investigating' they said 'the engine - could be a sticking injector or something''

lets say im not to optimistic!

i have filled it back up (1/2 tank) with bp ultima and it seems a bit better so im wondering if i got a dodgy load of fuel. changed the air filter this morning and it was original (manufacture date on it..can 2004 with 34 k on it) so i presume the fuel filter is too.....

I have a replacement fuel filter, now all i want to know is if i change the filter how do i purge the air/fill it with diesel (the other cars i have had had a pump on the filter head to do this but this is a canister with an in and out pipe a hole for a sensor??? in a straight pipe to go into (do you HAVE to have a new seal for that because this filter didn't come with one) and what looks like a bleed screw in the top in maybe a 6mm projection.

Roto you mentioned using vacume, do you just connect a vacuum source to the bleed screw then (after connecting everything up) - or am i completely miss guessing? Also can you use one of those 'remove the oil via the dipstick tube' vacume units - if so im up for buying one anyway!

all advice great fully received!

cheezemonkhai

I'd say could well be as that is exactly the effect a dirty air filter and fuel filer had on the old TDI 110 (non PD) engine.

HTH

EDIT:

Easiest way to prime the filter on those things is to pour some derv into them so it is already mostly full of derv. Make sure the battery is charged ok then crank it.

They for some reason decided to get rid of the nice primer button/bulb you found on older cars

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rotodiesel

Assuming the filter on your V6 is the same as the one fitted to the PD engines, there is an inlet stub, outlet stub (covered by a cap on a new filter) a hole with a slot for the "mickey mouse" clip which takes the thermostatically controlled "T" piece and a drain at the bottom.

A new filter should come with a pair if 'O' rings, one black and one blue for the "T" piece. If you didn't get these, you've probably bought a junk filter.

Filling a new filter with fuel does not always work on these engines in my experience - the new element is so absorbent that it's difficult to get it full. On a PD, I would not recommend running the tandem pump dry - it probably wouldn't do the transfer pump on the VE much good either - hence the vac pump. (Interestingly, VAG's own rework instructions (see Canadian vehicle recalls) for the tandem pump recall suggest pulling fuel through the tandem pump using a hand operated vac pump in order to prime it).

Observing the most scrupulous cleanliness at the outlet port of the filter, connect all the lines except the outlet and make sure that the drain is closed. Connect the vac pump to the outlet using clear line and a fuel trap and pull fuel through until it emerges from the fuel filter reasonably free of bubbles. Reconnect outlet pipe - job done.

My PD started instantly and ran without any hesitation when I used this method. If you don't have a vac pump, a 1 litre gearbox oil gun used in reverse will do just as well - you can squirt the fuel back into the tank at the car's fuel filler.

Remember, the V6 filter could be different - I've not seen one.

rotodiesel.

THE KICK INSIDE

The filter has the inlet and outlet pipes and the socket for the t-peice but no sealing rings its a 'wix' make (what the wife could get yesterday at short notice....) so i don't know what the quality is like but its heavy enough (normally a reasonable gauge of quality in filters i think!) interestingly i noticed its got no drain in the bottom either (but i havent had the original off to see if that has either!)

any thoughts on how vital fitting new seals is ( i know it being air tight is vital but im wondering if i can get away with the old seals just to see if it gets rid of my issues..)
to be honest im not confident about ANY VAG dealers and the 25 v6 tdi engine they al seem to say 'we dont see many of those' which roughly translates to we haven't a clue about anything the computer doesn't tell us' i suspect...

They didn't even suggest changing the fuel filter today and even i know enough about diesels that the first thing you change if its being 'weird' is the fuel filter...

anyway i do have a gearbox syringe...so i will give that a go on the output side to draw fuel in....

many thanks roto for your help believe me its appreciated...

rotodiesel

You might have gathered I have been in the diesel business and have tested many fuel filters. The only filters I would dream of using on my vehicle are OE (original equipment), Bosch or Mann & Hummel.

I fitted a Mann & Hummel to my PD 130 and it came with the 2 'O' rings.

Try the Wix filter if you are stuck - you can fit a better one later if it fixes the problem. The "T" piece is fragile, ease it out very carefully - especially if you have to re-use the seals. A little clean engine oil in the bore for the "T" piece will aid fitting. Don't ever use silicone grease - it's not soluble in fuel and will end up somewhere nasty.

Best of luck, let us know how you get on. If stuck, go to a Bosch diesel specialist - VAG dealers' knowledge is, in my experience, very limited.

rotodiesel.

THE KICK INSIDE

Thanks roto i gathered you had been around the block a few times!

I think im going to have go with the wix and see what gives, i planend to lubricate the rings with fuel (diesel being slippy stuff) and all, but i will take your advice on a smear of engine oil...

seems like a lot of bother compared to the mitsibushi filter on my wife's which does havea drain and a water warning light, and a hand pump/bleed screw and costs about 1/5 fora filter that this does (plus the filter is a bout 3 times the size...) that takes me about 10 minutes to change including removing the whole assembly from the bulkhead (perilously close tothe header tank with plastic nipples sticking out exactly where you would smack them if you put a strap wrench on it and slipped...so the wise man removes both pipes, un-bolts and splits on the bench!)

anyway i think i will do this first, if no cure then they can start playing with injectors etc - i have tried to use logic to see hat only effects idle that inst electrical...and i keep coming back to low fuel feed to the engine so start with te basics - filters!

Do i gather your not in the uk, if you were i would buy you a pint!

THE KICK INSIDE

Thanks for all the help guys but i totally failed to get the filter off the inlet and outlet pipes just wouldn't budge, the top of the filter (oem) was distorting under the strain so i decided discretion is the better part of valour and its going in to the dealers (where when something breaks at least they have parts)

I have to say this whole saga (combined with the stupid plenium design) has really taken the shine of ownership the whole design (like no water drain on the filter!!!!!) makes me question the whole viability if long term ownership and i think i will be returning to volvo or misubishi (did a whole engine service on my wifes this morning oil change and air an fuel filters in an hour)which at least i know are designed to be maintained.

When i have calmed down a bit i may take a more rational view but right now it seems these things are designed and maintained by the dealers to do 3 years and thats your lot - may as well have bought a vauxhall! Actually judging by the main dealer attempt to sell me a new skoda yesterday vauxhall would have made less of a horlix of that too!

As you may gather im not exactly happy! Again thanks for the help (especially roto)

THE KICK INSIDE

Well i sat down had a cup of tea and calmed down..called my brother in law and we managed to get the filter off (destroying the old on in the process!) those pipes were very well attached...

Anyway new filter on....and....no difference....

so it runs fine, idles ok when stone cold but as soon as its off cold running (1000 rpm idle) it drops to 800 rpm idle and its ok for a couple of seconds, then its like a 3 legged donkey...but the revs stay pretty constant...the needle may twitch but not much more than that....its just rough you can see the engine shaking....

Codes read- no codes

Guided diagnostics done - no codes

Air and fuel filter hanged - no change...

fuel tank topped up (1/2 tank) - no change....

Italian tune up done (5 miles 3000 rpm) - no change

Heres the interesting one....if you hold (say) 1100 rpm and gradually back it off to idel id does it immediately....if you rev it to 2500 rpm (say) and take your foot right off....the revs drop like a stone to 800 and are stable for a second or two...then it starts its 3 legged donkey impression....

Now if it was petrol i would say this was a sensor and the fast drop in revs causes the ecu to use a default setting, then once stable it uses the sensor feed (like a lambda sensor in a petrol) - the dealar says the electronics check out its mechanical (me i aint sure they know what they are looking at!)....anyone got any ideas/thoughts?

Supurbia

Do you know anyone local who has the same car?

If so try swapping airflow meters to eliminate this, check all the thin pipes going to the top of the air filter box, clean out the EGR valve and throttle body housing.

Other than that I'm stumped also without seeing it, have you jump started it recently, and if you did, did you connect the neg lead to the battery or an earth point? when ppl go live to live and neg to neg it can spike the ecu.

I know what a world of pain you must be in right now, Skoda are hopeless and unhelpful, their attitude is if theres no code cya.

cheezemonkhai

Does the Suberb has a drive by wire (eg potentiometer) accelearator?

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THE KICK INSIDE

thanks guys....

unfortunately 2.5 tdi's are pretty rare - see dealers 'we dont see many of those' - so i odnt know anyone i can borrow a maf off (htough i am suspecting either the maf or the temp sender more and more...

being a tdi as far as i am aware no throtle body (as no throtle butterfly) - not jump[ed it but i did have th battery off - ran fine afterwards (couple of hundred miles) before this started....

i really dont know about the drive by wire - this has just coem out of warrenty (so i havent been touching it)...also no manuals are available....which doesnt help matters..

as if the maf was open circuit or shorted i understand it would raise a code i am preusming it may be dirty...and the readin oculd be fluctuating, hopefully my vag-com will arrive tomorrow so i can look at he readings before it goes to the dealer - given i was walking around with a brochure for new superbs and talking about them they wernt exactly helpfull in making me think 'hmmm thats a good idea' more like 'no way i would buy a car off you, new or otherwise!'

THE KICK INSIDE

well i hooked it up to vag-com tonight....and ...nothing no stored codes...

anyone got any ideas at this point/

Supurbia

Muck the EGR out.