I went to the rolling road last month and like it did on the road it had small but noticeable hesitations all over the rev range, see attached graph. Since there was also a slight smell of warm oil in and near the engine bay we had to look further.

A mate of mine who happens to be a mechanic had a quick look into this before but without result. So today he took off the inlet manifold and within an hour he found the probable cause: a cracked breather hose, see the attached picture. I hope this settles everything, but to be sure we will get the injectors cleaned and valves replaced as well...

Very common failure on 1.8T's.

Yes, it is, just like vacuum lines, hoses, valves and splitter pipes. It seems the Y-pipe was already replaced by the previous owner. I hope this is it and that it will cure the the ups and downs in the curve. Otherwise the search continues...

Edited 22 June, 201610 yr by dcstuurman

The hose (and some others) have been replaced now, along with new diverter and waste gate regulator valve. Unfortunately this solved a lot, but there is still a slight hesitation on full throttle above 5000 rpm. Any ideas? Sparks are new (0.7 gap) and coils are recalled items... Oh and it has a generic 210 bhp map.

Edited 2 July, 20169 yr by dcstuurman

What are your intake temps doing? What cooler do you have? Could it be the ecu retarding timing above 36 degrees?

I will let my mate look into this, as I don't have any gauges other then the stock ones. He is a VAG mechanic, but annoyingly he doesn't have access to the full Skoda program due to legal rights. Luckily there is one device available he can chic this for me. The intercooler is stock, especially as I thought it wasn't necessary in this stage.

Edited 2 July, 20169 yr by dcstuurman

I will let my mate look into this, as I don't have any gauges other then the stock ones. He is a VAG mechanic, but annoyingly he doesn't have access to the full Skoda program due to legal rights. Luckily there is one device available he can chic this for me. The intercooler is stock, especially as I thought it wasn't necessary in this stage.

It should be ok by and large but at top end it probably will go above 36 so would be effected by the ecu adaptation...It could be a few things but that might be worth a look. How's your MAF?

At the top end of the Rev range you can also get TIP collapse if nothing has been done to increase airflow into and through the airbox. You won't get it standard but with a remap it's possible. Lots will say it doesn't happen but mine used to drop off like it was hitting a wall until I improved the airflow, now it goes right round to 6500 rpm

Under boost obviously, they will all Rev to 6500 without

Well my mate tried to log it yesterday evening, but without succes. He will try to take the old VAGCOM, which does allow it to log, so will be continued. Thanks for all the help thus far! Inlet temperature, MAF are on the suspicious list and so is TIP collapse. The guy from the rolling road (who cleaned my fuelinjectors for free, just to help!) also suggested fuel supply or particular the fuel pump. On the Dutch Seat forum there was a similar engined Leon that had similar issues after renewal of the cracked breather hose. That was fixed by slightly alteration of the waste gate tension (which they only recommend doing with VAGCOM). I really hope he is able to log it first, this will telltale a lot more...

I also think fuel pump may be where I'd look after all the above. Also if it's a tail off I would suspect actuator more or possibly TIP, but the fluttery line looks like retardation or possibly fueling to me.

I also think fuel pump may be where I'd look after all the above. Also if it's a tail off I would suspect actuator more or possibly TIP, but the fluttery line looks like retardation or possibly fueling to me.

Oh the flutter line was before we had the cracked hose fixed (and other things replaced). It is now way better than that apart from the above 5000 rpm hesitation, especially from 3rd gear onwards...

Totdat my mate had some time to hook the Skoda to a VAS 5051B. We had a warning for secondary airflow having an issue and battery a bit to low.

He then checked some of the parameters, but all seemed fine. He also calibrated the throttle (since it was body was refitted a few ago). The car now seems to be a little bit smoother.

We than had some little drives with the computer attached. The boost is measured at 2 places and the second one seems to measure thd same after a little lag. Boost is up to 1.2 in midrange, is that about correct for a mildly mapped engine? Will tightening result in s too much boost due to waste gate?

The MAF values seem to be right too. The hoses of the secondary pump seem to be in good order, but can a faulty pump or system result in my problems? What does TIP of TIP collapse mean? Throttle ???

Unfortunately when I went home the car still had 3 slightly hesitations above 5000 rpm in 4th gear.

Edited 9 July, 20169 yr by dcstuurman

Yesterday we reset the throttle and it is a bit smoother since. Today I went to the Nurburgring to "clean" the engine, but on the higher gears there is still a slight hesitation. So maybe it is the fuel pump, as this wasn't before the remap demanding more fuel (and boost). In other gears it is smooth as silk. And up to 5000-5500 rpm also (this wasn't the case a month ago). Oh nice side effect: a Caymann GT4 isn't that much fast from 60-100 mph... :-)

Good excuse to go Nordschleife, could be fuel starvation, upgrade to a sytec pump is usually the done thing.

Could it be a software issue?

It can always be a software issue, but I will try the fuel pump first, I think it's about the same pump I used to have in my Astra F C20LET back in the days (which really needed it because of massive starvation issues). Maybe a stupid question, but the Sytec is suited for 3 bar right? Because I have read on JBS site the more expensive LCR OEM upgrade is for 4 bar only?

Edited 10 July, 20169 yr by dcstuurman

It can always be a software issue, but I will try the fuel pump first, I think it's about the same pump I used to have in my Astra F C20LET back in the days (which really needed it because of massive starvation issues). Maybe a stupid question, but the Sytec is suited for 3 bar right? Because I have read on JBS site the more expensive LCR OEM upgrade is for 4 bar only?

To be honest it was a while ago I looked at them but I think they cover a range which is up to 4 bar max, might be wrong though, have a dig about there should be plenty out there. V popular upgrade.

Is it this one (there is no mention of the 3031 number I've read somewhere on this forum):

Thanks for all the help in all my threads and questions so far Yellow Car!

No worries, I'm trying lol. I just pulled up a thread off another forum where Badger Bill is saying they don't use sytec anymore and prefer the Walbro apparently...

http://www.glencoeltd.co.uk/walbro-motorsport-upgrade-in-tank-fuel-pump-kit-vw/

Think that's the one, unfortunately it was an upgrade I never got round to

Just got this item number off ebay mind... 181551527224, decent price, yeah I believe it should be 3031

Edited 10 July, 20169 yr by YellowCar

No worries, I'm trying lol. I just pulled up a thread off another forum where Badger Bill is saying they don't use sytec anymore and prefer the Walbro apparently...

http://www.glencoeltd.co.uk/walbro-motorsport-upgrade-in-tank-fuel-pump-kit-vw/

Think that's the one, unfortunately it was an upgrade I never got round to

It is indeed very confusing, always thought Walbro/FSE/Sytec was some sort of the same...

I could of course also go for the LCR route, the fuel pressure regulator will keep it to 3 bar anyway and it seem to be suited to well over 300 bhp and is perhaps quieter than the Walbro. If the tank has the same diameter is another question.

Will try to explore this week what is available in short term in Holland as next rolling road is in less than 2 weeks...

It is indeed very confusing, always thought Walbro/FSE/Sytec was some sort of the same...

I could of course also go for the LCR route, the fuel pressure regulator will keep it to 3 bar anyway and it seem to be suited to well over 300 bhp and is perhaps quieter than the Walbro. If the tank has the same diameter is another question.

Will try to explore this week what is available in short term in Holland as next rolling road is in less than 2 weeks...

Yeah I suppose the regulator should sort it out, worth looking into, think LCR should fit. Is that the one also in the S3?

According to JBS there is a version for 2wd and 4wd Octavia's. One is from the LCR, the other from the TT225 it seems. I've read somewhere on a Dutch Seat forum the S3 has a split tank or something and needs modifications. JBS rates this to 350 bhp and part number is 8L0919051H and apparently it is also found on the Gallardo. Perhaps that is the reason why it is bloody expensive compared to Walbro...

Ah yes I think there is something about an expansion tank on the S3 which may complicate matters. The Sytec pump goes straight in though, there is a how to guide kicking around somewhere here...