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phil p
24-02-2008, 05:16 PM
Hi Im new to these forums but gonna give it a go. So here goes. I've had a 2001 octavia tdi 110bhp elegance for 3 years now and its been excellent apart from on the odd occasion iiit suddenly looses power with no excess smoke or noise. If I stop the engine for a second and restart it its fine as if nothing ever happened. It seems to be getting more frequent. has anyone else experienced this kind of problem or got any ideas of what to check ? Im not scared of getting my hands dirty.

Thanks in advance :confused: Phil.

STEWY L
24-02-2008, 06:04 PM
Hi Im new to these forums but gonna give it a go. So here goes. I've had a 2001 octavia tdi 110bhp elegance for 3 years now and its been excellent apart from on the odd occasion iiit suddenly looses power with no excess smoke or noise. If I stop the engine for a second and restart it its fine as if nothing ever happened. It seems to be getting more frequent. has anyone else experienced this kind of problem or got any ideas of what to check ? Im not scared of getting my hands dirty.

Thanks in advance :confused: Phil.
hello phil and welcome to the forum. i'm quite sure that some one will give you the answer, but in the meantime, have you tried the "search" facility?
i'm sure i have seen similar threads on here, i joined in november of last year and in reading through previous stuff i'm sure it's on here a few times.
i don't have the knowledge of vw, and have thankfully had no probs with my bora up to date, so haven't had to learn much about them yet, but if learn is what your after, then you are definately in the right place. their are guys on here who live and breath vag, and all too happy to help, but do a search first,
it's definately on here,
good luck

phil p
24-02-2008, 06:59 PM
Thanks for the advise. I've had a look at some of the other probs people have had and it sounds pretty common that the MAF sensor can give problems. I think I will try disconnecting it and give it a spin if the problem comes back then I will get one and try it. The car has done 127000miles and given me no greef before I think it deserves it. I will let you know the outcome.

Many thanks. Phil.

mluton
24-02-2008, 07:07 PM
Post over on www.briskoda.net you might get more of an answer

Welcome to the forum

Might be worth disconnecting the MAF, see if the car acts normally.

Crasher
24-02-2008, 07:11 PM
NO, don't disconnect it!!! I wish people would stop advising this, it is 8100dy stupid!!!!!!! If you disconnect it, it may not show any difference and it WILL store a fault code so confusing the poor flaming mechanic reading the codes when you get them read so you may end up with a new one when it isn’t faulty. Get the car read for codes and if there are none, buy a genuine AMM from a Skoda dealer, they are very reasonably priced and guaranteed for two years.

greg123
29-02-2008, 08:54 PM
Hi Phil,

This is a fault I deal with commonly. It is most likely the vnt turbo vanes and should NOT require a recon of the turbo, just a service/rebuild of the vnt end. There are a few simple checks that can be done including a N75 output cycle test & a startup test, as well as a road test plotting requested vs actual boost - this coupled with the fault code check will reveal if it's the likely turbo overboost condition causing the problem. Before the turbo is whipped off for repair, the vacuum lines should all be checked/replaced, actuator checked and in line with the above the N75 tested. It can be the control system, however more often it's the turbo.

There is a good guide with pictures on tdiclub, maybe here even, if you search. Don't do what a guy phoning me up for help the last week did and send the turbo to a shop that rebuilt ALL of it even though it was working fine, new turbo on car same problem, mechanic not experienced in computer diagnostics said it was the MAF then the MAP then the ECU - he is now a few hundred quid down and to my knowledge when we last spoke he still hadn't had a proper fault code scan or N75 (turbo control valve) test....

As it happens I have an octavia just like yours coming in for the very same reason. It's common. FYI, if it's the vnt seizing the reason for this is mainly not driving the car hard enough particularly not taking it up to 3k revs regularly and the 'lugging' (making the engine pull at 1,500rpm) of the engine the combination of which means the vnt doesn't get exercises and a good dose of hot exhaust to blow the carbon out, eventually it soots up so bad it can't operate any more and the vanes get stuck in the 'full boost' mode. This is in my opinion compounded by the EGR and breather issues that cause severe sooting up in the engine, particularly the intake which in turn restricts the flow of air and tends to make the turbo boost spike up due to the restriction. I disable the EGR on vehicles I manage. (not via software, this puts the engine into an inefficient mode).

If you need any advice please post back or pm me for contact details (I don't want to get knuckles wrapped for advertising!) for free phone/email advice. There are many threads on this and I'd concentrate on finding (or doing if you have one) someone who can carry out a full code scan with vag-com so you can give us some more information.

HTH, Greg.


Hi Im new to these forums but gonna give it a go. So here goes. I've had a 2001 octavia tdi 110bhp elegance for 3 years now and its been excellent apart from on the odd occasion iiit suddenly looses power with no excess smoke or noise. If I stop the engine for a second and restart it its fine as if nothing ever happened. It seems to be getting more frequent. has anyone else experienced this kind of problem or got any ideas of what to check ? Im not scared of getting my hands dirty.

Thanks in advance :confused: Phil.

Crasher
01-03-2008, 03:54 PM
Greg, it still astonishes me how reluctant people are to get a £28 fault code read done and how many hundreds they will spend to avoid it, I get very frustrated by it and it sounds like you do as well.

Paul Jay
01-03-2008, 04:20 PM
Hi All

Noted that Greg disables the EGR, how is this done and what the benefits/pitfalls?

My EGR is very dirty and I planned to clean it up, but might just replace it instead.

My own car has covered 107K but I make sure that it gets a regular blast to keep the turbo vanes freed up - hopefully should avoid problems above.

greg123
01-03-2008, 04:57 PM
Too right buddy, too right. I do it free when any work/servicing is carried out and I don't really think people appreciate that either. I'm still nowhere near paying off the kit and laptop (I'm part time working from home). Oh well!


Greg, it still astonishes me how reluctant people are to get a £28 fault code read done and how many hundreds they will spend to avoid it, I get very frustrated by it and it sounds like you do as well.

greg123
01-03-2008, 05:08 PM
Pitfalls are that a) it may not pass the type approval emissions regulations (not an issue, that applys to mfr's submitting new cars for testing before sale) & b) if in USA or other country it MAY not pass the inspection, over here the ones I have done do NOT put an engine warning light on, but NA models I gather by legislation have to have a warning displayed if the EGR is disabled so that then causes it to fail the annual test. It WILL pass mot and related tests. Smoke levels may actually be lower!

Benifits, would take me too long to write. Not least keeps the engine clean and avoids plugging the intake manifold with soot. Better mpg, less smoke, better running - possibly less oil contamination and turbo sooting though I can't verify that.

I simply use a metal gasket to blank off the egr pipe on the exhaust manifold. I have also disconnected and plugged the anti-shudder valve vacuum pipe - this is not recommended, it's because I read that the valve opens partially when the EGR is operating to cause the exhaust gasses to flow through - I do not know if this is true. I'm going to experiemnt to see if the anti-shudder valve operates during driving so I know, as it's best to have it enabled in case of engine 'run on' if a turbo blows. If anyone here knows the definitive answer to this, I'd appreciate it. With the anti-shudder valve disabled the engine is no worse than any other (most diesels don't come with one) it's just I'd like to enable it again once I know I can.

Any thoughts on the above please let me know. I can say that the blanking plate and disconnect anti-shudder works perfectly.

Next step is to route the breather to oil trap & air, done this on my XUD and others and it stops the engine 'sucking' engine blow by out un-necessarily and contaminating the intake system, coating the intercooler with oil etc. Once that's done we'll have a totally clean and clean intake system ;-)

Greg.


Hi All

Noted that Greg disables the EGR, how is this done and what the benefits/pitfalls?

My EGR is very dirty and I planned to clean it up, but might just replace it instead.

My own car has covered 107K but I make sure that it gets a regular blast to keep the turbo vanes freed up - hopefully should avoid problems above.

Crasher
02-03-2008, 03:22 PM
VEP (not PD) TDI's can have the EGR flow shut off in Adaptation 10.

greg123
02-03-2008, 10:32 PM
True. However I have a couple of reasons for not doing that - correct me on them if my logic is faulty:

1) the egr valve it's self gets gummed up to high heaven, resulting I have seen in valves jacked open by the crud. For that reason, egr would be sucking all the time, even if disabled in software - a blanking plate eliminates this.

2) in the US models for certain, but I'm unsure of UK models. when the egr is disabled in software to compensate the engine tries to reduce emissions and reduced performance and economy results as the engine 'tune' and timing is altered - this was proven on the us forum some time ago when people were trying to figure why their cars didn't drive as well and used more fuel with egr off. The reason they didn't blank plate is that it puts the engine management warning light on (CEL) on US spec cars, but not UK spec.

For the above reasons I went the plate gasket route. Your comments appreciated - I'd also like to know for sure if the Anti-Shudder valve has ANY relation to EGR in the uk (been suggested partial shutting helps the egr draw through)

Greg.


VEP (not PD) TDI's can have the EGR flow shut off in Adaptation 10.

Crasher
03-03-2008, 02:07 PM
Well I don’t turn off or disconnect the EGR system as I don’t believe in increasing a vehicles emissions if it can be avoided but I have played with that function and found some extra power and left it dialled right out only on one car owned by a friend of mine and that was about four years ago. A week or two back he had 17965 from clogged vanes and the inlet manifold, although still dirty, was much less clogged up than usual. I played with the anti shudder on that as well and found a tiny bit more power from that.

greg123
03-03-2008, 02:59 PM
Yeah, even dialed back it will still clog up the manifold. Interesting what you say bout emissions, however disabling (blanking) egr will decrease some emissions. It depends what the governments had it in for when they made the rules, egr means less oxygen and increase of certain emissions and reduction in power & mpg. In particularl use of EGR increases soot and cancer causing particulates. But it reduces Nox. Though, if I recall right, it increases CO2 which is now recognises as a major issue (EGR was developed before climate and CO2 issues came up the agenda). Just saying 'emissions' is hard to qualify, as a measure to reduce some often raises others.

Cup of tea time!

Greg.


Well I don’t turn off or disconnect the EGR system as I don’t believe in increasing a vehicles emissions if it can be avoided but I have played with that function and found some extra power and left it dialled right out only on one car owned by a friend of mine and that was about four years ago. A week or two back he had 17965 from clogged vanes and the inlet manifold, although still dirty, was much less clogged up than usual. I played with the anti shudder on that as well and found a tiny bit more power from that.

phil p
03-03-2008, 11:08 PM
Pitfalls are that a) it may not pass the type approval emissions regulations (not an issue, that applys to mfr's submitting new cars for testing before sale) & b) if in USA or other country it MAY not pass the inspection, over here the ones I have done do NOT put an engine warning light on, but NA models I gather by legislation have to have a warning displayed if the EGR is disabled so that then causes it to fail the annual test. It WILL pass mot and related tests. Smoke levels may actually be lower!

Benifits, would take me too long to write. Not least keeps the engine clean and avoids plugging the intake manifold with soot. Better mpg, less smoke, better running - possibly less oil contamination and turbo sooting though I can't verify that.

I simply use a metal gasket to blank off the egr pipe on the exhaust manifold. I have also disconnected and plugged the anti-shudder valve vacuum pipe - this is not recommended, it's because I read that the valve opens partially when the EGR is operating to cause the exhaust gasses to flow through - I do not know if this is true. I'm going to experiemnt to see if the anti-shudder valve operates during driving so I know, as it's best to have it enabled in case of engine 'run on' if a turbo blows. If anyone here knows the definitive answer to this, I'd appreciate it. With the anti-shudder valve disabled the engine is no worse than any other (most diesels don't come with one) it's just I'd like to enable it again once I know I can.

Any thoughts on the above please let me know. I can say that the blanking plate and disconnect anti-shudder works perfectly.

Next step is to route the breather to oil trap & air, done this on my XUD and others and it stops the engine 'sucking' engine blow by out un-necessarily and contaminating the intake system, coating the intercooler with oil etc. Once that's done we'll have a totally clean and clean intake system ;-)

Greg.
Hi thanks for replying Im gonna give the EGR route a try as I've had dealings with these on many trucks and light vans ( transits in particular) the engine runs absolutely smooth silk normaly so it was a bit worrying at first when it did it. but as for the not giving it a blow out I normally drive on the torque between 1400rpm and 2500rpm and take it to the limiter once a day maybe. So Im not helping it. If this doesn't work. I take it that VNT means variable nozzle turbo ? and is it a case of just giving it a damn good clean and de-coke or dose it have to come apart and be ballanced when put back together ?

greg123
03-03-2008, 11:18 PM
Hey Phil,

Yes running to 2.5k only isn't really enough. You don't have to do it all the time but when warm 'exercising' up to 3k regularly is good, you don't have to use a lot of throttle at those revs on light load the vnt vanes will have moved across. Regular moving of the vanes stops them sticking up.

To fix, yes it's turbo off - there is a thread on tdiclub.com with pics but if you are not happy with stripping out turbos give it to someone. A new oil line is needed, other than that no balancing etc as the turbo shaft/turbine isn't touched, just the casing split and the vnt 'vanes' are dismantled, cleaned up and refitted all shiny and ready to go for another - well forever, hopefully if you engine is well serviced and you drive it right.

If you turbo didn't give any other issues don't let someone con you into a recon turbo, this is a couple of hours labour only - no parts - for a turbo shop, other than the oil line which isn't that much.

Greg.

phil p
07-03-2008, 11:31 PM
Hi Greg.
I,ve cleaned out the EGR it was gummed up to hi heaven. also I've took your advise and given it a good blast up the motorway leaving it in 3rd and 4th and my god after a trail of black soot for 4 miles what a difference its smoother quieter and no more power dropping off when I boot it. I didnt notice any changes in performance as its probably been dropping off very gradually, and it passed its mot no problem last october. So thanks a million I could have spent a small fortune when all it needed was a blow out. I will probably block off the EGR altogether at some point in the future but Im well happy with it again now.

Cheers. Phil.

greg123
09-03-2008, 10:54 PM
Hey Phil,

Glad I could help ;-)

Yes get the egr blanked, clean the inlet manifold if it hasn't been already and the valves (use a vacuum while you do it or bits will go in the engine). Sounds as if you may be lucky, you gave it a good boot just as the vanes started to get sticky. Regularly boot it and rev up to 3k before changing gear when warm and hopefully the carbon will burn off and your vanes willb e okay and you won't need the turbo removing!

Greg.

alexutz1980
12-04-2008, 08:14 AM
Check tank fuel pump. Maybe some rezidues down there (it has filter).

greg123
12-04-2008, 09:36 AM
This vehicle does not have a fuel pump in tank, it has a VP37 Bosch IP with the internal lift pump. It may be a fair point about tank or filters being blocked - I think I suggested some time ago the IP was run directly off two clean lines in a clean bottle of diesel thus eliminating the entire fuel supply/return system and I don't think that helped (if the o.p. carried out that test) leading one to beleive it's not a fuel supply problem.

OP please feed back where you got to with this.

Greg.


Check tank fuel pump. Maybe some rezidues down there (it has filter).