octaviadan

Having my 110 Elegance done next week - still going well? What fuel economy are you getting?? Dan

The CTS has two circuits; one for the instrument readout and one to inform the ECU. They can fail on either, or both, circuits. Mine failed on the ECU circuit as my temperature readout was fine. Fault was picked up by VCDS. If the CTS sensor has failed, the engine will use more fuel if the reading from the sensor is telling the ECU that the temperature of the coolant is cooler than it actually is and will overfuel. Not sure what the heater issue is but should be a constant steady flow at whatever temperature. Maybe you have an air lock after the cambelt and waterpump change?

At half a tank, I am usually about 270-280 miles so really is using far more fuel than it should.... Once you have found someone local to do a VCDS scan, I would also do some runs to test the MAF using the measuring blocks (can't remember which group it is though - someone will confirm!). CTS is a common issue - is yours still the original black one or the upgraded green one?

Do at least a couple of brim-to-brim re-fuels and work it out manually - that will give you the accurate figure. Even if your fuel computer is inaccurate, yours does seem to be using much more diesel than others on the forum. Are you sure you have no other issues? Have you had a code scan on VCDS? Any excessive black smoke when you accellerate hard? Other items which could cause yours to use more fuel is CTS (Coolant Temperature Sensor) and MAF sensor. When you had the cambelt done, did the garage set the timing up on VCDS? This could also be issue if not set up correctly. Have you any performance issues? Dan

Mine is also always 10mpg out (i.e over-reading by 10mpg) on my fuel computer. I always reset reading '2' at every refill and according to fuel computer over the tank I average approx 60-61mpg however working it out manually, the figures are consistently around the 50mpg mark.

My 110 Elegance fuel computer is inaccurate - it tends to overread by around 10mpg and after fill up computer states I have around 700 miles of fuel!! Realistically from full to 'light on' I have covered around 470 to 490 miles. The only way is to work it out accurately is from brim to brim fills and by doing the calculations yourself. For the record my Octavia has averaged exactly 50mpg over records taken on 39 separate brim-to-brim re-fuellings (best being 53.2mpg; worst 46.1mpg), covering approx 400 miles per week with at least 3 to 4 days undertaking a 70 mile round commute, mixture of A roads (mostly 50mph limit) and some city driving. These engines do seem to vary a lot with fuel consumption and performance - think mine is an 'average' 110 on consumption and performance, despite all turbo issues sorted. I find that regular routine servicing helps. Always change your air filter at 10k miles (not at the recommended 40k!) that always makes a big difference with performance and economy. Hope this helps Dan

TPS Nottingham always serves me - depends on the manager I think but 'a sale is a sale'!

I had a 2001 (Y reg) ALH TDI Ambiente which had a VNT turbo. I think pre-facelift Mk1 Octavia's with 90bhp TDI had a wastegate turbo. Dan

Logging boost values is done via VCDS/VAG-COM as Fordfan says. I followed this guide on the MKIV forum see link here: http://uk-mkivs.net/...spx?PageIndex=1 which I managed to do ok but posted my findings and nobody replied!! I did post my graph on here and the TDI experts confirmed all ok. For info, the graph I plotted is here http://www.flickr.co.../in/photostream which is what it should look like if everything is working properly! Dan

Ok, so I think that perhaps we can rule out MAF problems. Re issues with fuel consumption, after the Mr. Muscle clean the turbo 'should' be running more efficiently, hence producing more boost so would need less fuel to make the car move, unless however you are constantly booting it... My fuel consumption improved after my new (hence clean) turbo - about 2-3mpg overall. I do find though that motorway running does use slightly more than A road work as even if you are sticking to the 70 limit, generally the engine is revolving faster than a 60 limited A road. My daily commute of 35 miles each way typically achieves 65+mpg, whereas a constant motorway run at a steady 70 returns high 50's to low 60's. These figures are from the fuel computer and that does overread between 5-10mpg at times! To me your problem sounds like a blockage somewhere either fuel or exhaust. Have you changed the fuel filter recently or run some fuel additive through? If not, that maybe worth a try. I found 'Silverhook' Diesel treatment very effective with mine. Also check the exhaust, that could be partially blocked, maybe by some carbon cleaned off the turbo?? Dan

Try unplugging the MAF and then take it out for a spin (one minute job). If it runs better then it is very likely that the MAF that is at fault, but this could be one of several issues causing your car not to perform. It also sounds as though it could be sticky vanes in the VNT although you say that you have done the 'Mr Muscle' clean. I am wondering if it needs a further go as there is still some carbon is there or maybe some rust in there that could be causing it to stick (which Mr. Muscle won't remove!). It took me ages to get mine right and I eventually replaced everything that can cause performance issues as previously listed - it really is a process of elimination. Skoda themselves have a reputation for replacing everything listed above until the car performs as it should! Have a play over the weekend and see how you go on! It would be beneficial for a VCDS code scan though. Can anyone help r4c with a code scan? He lives in Ayrshire Dan

Really the intake manifold should be cleaned off the engine block as scraping the crud out in situ risks debris dropping into the engine with potential catastrophic results.... You maybe losing a bit of vacuum from that thin vac pipe but would'nt cause some of the issues you have been experiencing - maybe some underboosting but nothing else. Replace it anyway as a matter of course. Have you checked the rest of the pipework right back to the vacuum sphere? I had a very thin/weak pipe near to that. Re the actuator arm, a strong resistance is normal as you are pushing against a strong spring in the actuator body so you will need a socket extension or screwdriver to move it. If it feels free through its travel then there is little carbon/rust present causing sticky vanes, if it feels 'gritty' or has some resistance through its travel then there is carbon/rust present which if bad enough can cause boost issues. Another thing you could try is to unplug the MAF sensor to see if the car runs any better unplugged. This will cause a error code log when you read the codes with VCDS by doing this. If the car runs better then it is very likely that the MAF is goosed - this is a very common problem. There are loads of threads on here if you do a search. Dan

Just re-reading your posts, how did you clean the EGR? Did you remove it from the intake manifold? It would have been better to remove the intake manifold as well as if your EGR was caked, the intake manifold would be clagged up as well, restricting boost pressure into the engine. I am also wondering if you have removed some pipework when using the 'Mr Muscle' method to clean the turbo, you may have created an air/boost leak if all hoses/anciliaries have not been put back together quite right, so worth checking. Dan

Lofty79 is in Perthshire but my geographical knowledge of Scotland is not great so not sure how local he is to you! I am sure that there is someone on here in Ayrshire who can help? It might be an idea to edit the name of your topic to include 'TDI' - you will then attract the regulars with perhaps more knowledge of TDI issues than me!! Dan

Strong diesel fumes smell sounds as though it is running very rich so I think it could be a duff CTS, however a code scan should reveal this. Rather than trying to source a lead for VCDS, isn't there someone local on here who would scan it for you for a couple of beers? Where abouts are you situated?

Hi and welcome to the forum! Firstly have you done a code read on it on VCDS/VAG-COM? I would start with that which should give some indication of what could be going on. This could be a various issues and by doing the code read first, this should help identifying the problem. Sounds as though this could be: -MAF -CTS -N75 -restricted EGR/intake manifold Strong diesel smell is definitely not normal. Have you checked all fuel lines? Does the car smoke especially when you boot it? Dan

It looked a bit awkward to get at and as I wanted to clean the IC it was the best way for me. Wasn't awkward or difficult or particularly time consuming I think it took me just over an hour including flushing out and cleaning the IC.

Mbames, it would be a PITA to change the MAP in situ. The easiest way to do it is to remove the intercooler. I removed the front bumper, o/s headlight and indicator to get easy access to the intercooler mounting bolts. This is quite a easy task and only takes about 20 mins or so to remove all this. The trickiest bit is removing those strong spring clamps which hold the boost pipes onto the intercooler. Once the intercooler is off, try the MAP sensor mounting screws as they can be very tight as the screws can rust into the plastic body of the IC so you can easily chew up the screw heads..I was lucky with mine as they loosened and came out no problem. Give the IC a good clean by flushing it through with some solvent like carb/brake cleaner or petrol and make sure it is fully dry before refitting. Re-assemble everything in reverse order to removal making sure to reconnect all electrical plugs. You might find that bottom IC mounting bolt a bit of a pig to put back in - I managed to strip the threads on that one! Once all back together, before you start back up, remove the top intake pipe at the EGR side and start without this connected. Engine will sound very loud but this will ensue that the boost pressure blows through any remnants of solvent cleaner in the IC without it entering into the intake manifold. I am sure you will notice an immediate improvement but I think sometimes with these cars it takes a 1000 miles or so before all settles down and the ECU is used to its new 'settings'. Let us know how you get on! Dan

Sorry to resurrect a slightly old post but thought I would update you re my Octavia. One of my previous posts I loaded up a boost log, which looked fine to me and was confirmed by mbames et al that this all looked good. A couple of weeks previous to the boost log I did change the final thing which can cause boost issues on our TDi's which was the MAP sensor on top of the intercooler (I also flushed this out but was not fouled in any way), even though there were no issues logged with the performance of the MAP according to VCDS. Anyway I did some of the final checks as suggested including the VNT mechanism checks and also the TDi timing on VCDS, all of which are working or set as it should be. Following this I have since been away on a family hoilday to Suffolk so a good long fast run on A1 and A14 etc there and back and it ran absolutely perfect - best it has ever performed! A couple of weeks have passed since and my Octy is back into its usual weekly running routine and I have to say that it is still running very well - picking up and boosting all through the rev range as I imagine it should do - it really does seem to drive like a new car! Also I have noticed an improvement with fuel consumption as I now get 500+ miles on a full tank before the light comes on (before it was 450 - 470 at best). I think I can conclude that at last that I have finally solved the boost/performance issue, following fitting a new MAP sensor. So if you have replaced everything else as I have to try and get your TDi running and performing as it should, replace the MAP sensor on top of the intercooler with a new fresh one - they only cost about £25 and it may finally solve your problems.... Finally just want to say thanks to eveyone for their help and advice, all very much appreciated Dan

Ooh err missus!!! LOL!!! Apologies, I will re-word my post to remove the potential 'innuendo' to: I will disconnect the vacuum hose from the N75 valve and apply suction to the hose to create vacuum to enable to test movement in the VNT actuator!!! It is unlikely that I will be able to carry out such a test until the weekend!

Will whip it off and give it a good suck.....

Thanks Trundlenut will have a look and check the timing!

Hi mbames Thanks for confirming my boost figures are ok! It had a recon turbo (from Midland Turbo Nottingham) at 108k - now done 115k so should still be soot free. I have pressure tested the vac lines a few times (before and after turbo fitted) all seemed fine however I have renewed lines that were looking ropey as previously explained. Will check again though. Am wondering whether it is a fuel problem I have rather than turbo/boost? Trundlenut has suggested checking tdi timing on VCDS. Wanted to do that the other night but couldn't find it on VCDS. Can you advise how I do it? Thanks for advice so far! Dan

This is all very interesting reading. I've had issues with my previous Octy 90bhp Ambiente and my current 110 Elegance. Never got around to removing and cleaning/replacing turbo on my Ambiente - the only thing I did with that was use 'Innotec' (cost about £40 but made little difference) and replaced a couple of vac pipes, MAF and a split intercooler. It had good and bad days but never went into limp mode but was overboosting due to sticky vanes. Was always very economical however and had done 168k when traded in for my wifes 100PD Bora. The 110 Elegance on the other hand had 85k on the clock when I bought that 18 months ago (now has 115k). Anyhow, had similar symptoms to my 90 Ambiente and again didn't get proper 'limp' but wasn't boosting as it should. Went to town on this and had recon turbo (fitted myself), which included full clean of inlet manifold (badly gunged up), EGR blank, new N75 and most of vac pipes replaced. MAF was replaced not long after I first got the car and temp sensor was replaced earlier this year. Despite all this, it doesn't seem to have made a real noticable difference and I really do feel that at times it is quite 'lazy' in performance. Fuel consumption has always been worse than my previous Ambiente, and again only a very small decrease in overall fuel consumption despite all this work. The only thing I hadn't replaced was the MAP sensor on top of the intercooler, so got one of those and fitted this a couple of weeks back. This has made a further difference and fuel consumption has improved a bit more (nearer the Ambiente figures), but still don't think that it performs as it should. Overall performance I feel is no better than my Ambiente was, despite supposingly having an extra 20bhp! I have used a couple of different additives including Millers and Silver Hook (Silver Hook made a noticable difference when I first used it) however the effects soon wear off and back to 'normality'. My brother also has a 110 Elegance (but an Estate) with nearly 200k on the clock. Prior to his ownership, it has had the same work done as mine with turbo, MAF, EGR blank etc, however his pulls much better than mine, especially over 3000rpm it really noticable! So what is wrong with mine? Really don't think I am getting the full 110bhp. I am thinking of taking it for a rolling road to check bhp output but again all this is extra expense. I have had boost checks and it has been confirmed that it is boosting as it should, however I have managed to borrow VCDS off my brother and have done a boost log and plotted my self in Excel. Please have a look at the attached link to see what you think (post new MAP)? http://www.flickr.com/photos/16049116@N06/7749148698/ Despite all this, these are great cars but they can be a real pain in the a***!! Dan

I'm a bit of a dope when it comes to upto date technology, so want to ask if this is available for Blackberry? If so how does this all work? Could do with looking at monitoring MAF and MAP readings - not convinced my 110 TDI is performing right even though it has had all the usual things replaced (i.e. turbo, MAF, N75, EGR blank etc). Should really fly after all this work (well for a 110 anyway!) but is still a bit of a slug....