Hi all,

Just a quick one, and I realise this has been covered quite a few times, albeit in slightly different ways…

I have just bought a 2004 Octavia vRS, and I love it. The car drives extremely well, and there is nothing to make me doubt its health whatsoever, however a friend of mine has one, which is a lot quicker, especially at the top end of the revs, and even more so after the top end of 3rd gear. The turbo spools up at 1800RPM as expected, but seems to run out of puff after 4000-5000RPM, and the engine note seems to overpower the noise from the turbo. I realise that they only have a small turbo, but having had no experience with turbocharged cars before, my knowledge is quite limited. As far as we know, my friend’s car is totally standard, however it pulls much strong through the revs than mine, and the whistle from the turbo doesn’t really ease up until nearer 6000RPM. We are now suspecting that his has had a remap at some point. I have already cleaned the throttle body, as when I got the car it was a bit rough at idle, and had a hesitation just as it came on boost. It drives better now I have done this. The car has no engine management lights on.

One question I have is, on a standard vRS, should you hear the ‘dump’ from the turbo when changing gear or easing off the power at higher revs, for example 6000RPM? I’m just wondering whether I have a slight issue with a sensor that drops the boost off too early.

Sam

The first thing I would do is scan it for fault codes. Failing that take it to a skoda garage and get them to reflash the ecu with the standard map and get their opinion.

Thanks for that. Am I correct in assuming that there could be fault codes stored within the ecu that will not necessarily through an engine light up?

Yes scanned mine the other week. No Lights on dash but had 13 codes iirc

Thanks for that. Am I correct in assuming that there could be fault codes stored within the ecu that will not necessarily through an engine light up?

Yes there are lots of codes that are stored but don't turn on the engine light.

There is a dump noise, but it is quiet compared to boy racer dump valves. VAG 1.8T recirculate the waste air rather than dumping it to atmosphere.

It does sound like your mate is is running a remap and or even a different turbo :p

Yes there are lots of codes that are stored but don't turn on the engine light.

There is a dump noise, but it is quiet compared to boy racer dump valves. VAG 1.8T recirculate the waste air rather than dumping it to atmosphere.

It does sound like your mate is is running a remap and or even a different turbo :p

Yes I am aware the dump is quiet due to the recirc valve, just wondered if it was likely that my mates has actually been remapped, as the guy he bought it off told him it was standard, and had owned it from new... Strange lol.

Thanks for all the advice, I will go and get it scanned later.

Right, had codes read this afternoon, and found two faults:

MAF - Low air flow reading

And the usual 17705 is it? Boost/air leak somewhere.

I shall have a look this weekend. Any ideas?

I guess the MAF could be linked so i'll grab one off a mate.

Unplug the maf and see if it drives any different.

It it's better then there is an issue with the maf.

sort the boost leak as this can cause issues for the maf as it may be getting unmetered air in the system. Search on here for boost leak and it will point you in the direction of suspect pipes.

sort the boost leak as this can cause issues for the maf as it may be getting unmetered air in the system. Search on here for boost leak and it will point you in the direction of suspect pipes.

I drove it briefly with the MAF disconnected, and to be honset it felt pretty much the same. I've seen a few threads about the suspect pipes, but now I know it is a leak, i'll have a look in more detail.

Thanks for all the advice

Could be the pancake pipe that connects to the intercooler.

Quick question, do you have to clear fault codes from the ecu for the problem to go away? I mean, if for instance I cure a problem, by say replacing a pipe which has split, causing the 17705 fault code to be stored within the ecu, would the code need clearing from the ecu in order for the car to drive and boost correctly?

Some will sort themselves when the problem is sorted but i don't think a stored code will affect the running of the engine if the fault is no longer present

Well i've had a good look today at a lot of the pipes, mainly the smaller ones, and the only thing that I noticed is one of the small breather hoses that connects to the underside of the inlet seems to collapse when the engine is running, but is fine when switched off. Is this likely to cause an issue?

We have tried my friends MAF and recirc valve, and the car drives the same. We haven't tried the N75.

We did find that my friends so-called standard car has a Forge recirc valve, so we are now wondering if it has been mapped. It seems very quick and pulls very strongly to the redline. It's also quite a handful when accelerating.

Is there any way of telling if a car has had a remap?

If you have vag-com you can look at the requested boost pressure, and airflow rate, and you should be able to tell.

mock up a boost gauge on it, if its around 19psi then it's mapped.

mock up a boost gauge on it, if its around 19psi then it's mapped.

Excuse my ignorance, but how exactly do you do that? obviously I would need a gauge and some piping.

Quick update, I have read that this particular pipe can be an issue, so i'm wondering whether it's likely to be the cause of the problem...

http://cgi.ebay.co.uk/VW-GOLF-MK4-BORA-LEON-1-8T-AUM-INLET-PCV-BREATHER-PIPE-/160581630890?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2563693baa

Visually, it looks ok, if not a bit soft, however when i turn the engine on, it collapses, and I assume it is sucking in air somewhere. Is this likely to create boost problems?

Sam

A pipe is not meant to collapse, so sounds dodgy.

A pipe is not meant to collapse, so sounds dodgy.

I realise that lol, just wondered if anyone has had a similar problem which turned out to be related to boost issues. Thanks for the advice, I think i'm going to replace most with silicone versions to prevent future problems.

Thanks alot

I realise that lol, just wondered if anyone has had a similar problem which turned out to be related to boost issues. Thanks for the advice, I think i'm going to replace most with silicone versions to prevent future problems.

Thanks alot

I replaced that hose last year (with another standard one) as I was getting a boost hesitation, once I removed the pipe I found that it had a big split in it, once replaced the boost hesitation was gone

Edited 25 May, 201115 yr by Nickbes

I replaced that hose last year (with another standard one) as I was getting a boost hesitation, once I removed the pipe I found that it had a big split in it, once replaced the boost hesitation was gone

Sounds about right, though mine isn't so much a hesitation, but more like its just losing boost towards the top of the revs. I guess though if it has collapsed it will be strangling the whole system.

Thanks for your help.