Worried

[Velsheda]

It's pretty much all Ldn (rush hour) driving, but between 18-25mpg (with that being inversely correlated with time spent at lights & in jams). Been about that since new...no drastic drops.

lurches and cant make up its mind when to give you drive.

That's exactly it - exactly the same feeling. Makes you look a complete tw** at exactly the wrong time!

Off to garage it is then.
Thanks to all for the feedback - I will report back here with an update.

[Teutonic_Tamer]

whats MAF, same as mechatronics thingy?

The Mass Air Filter

Not quite - MAF actually stands for 'mass airflow' - and should therefore correctly, when abbreviated, be called a 'MAF sensor' !!!   

And it definately does not do any 'filtering' of the air. 

- it is a sensor which detects the flow of air coming into the engine for combustion and then sends on the info to the ECU (Engine Control Unit), which in turn determines the amount of fuel to mix with it.

Sort of correct.  It actually detects the actuall 'mass' or weight of the air entering the engine - along with the temperature of the said air.  This raw data is sent to the ECU, whereby the total content of oxygen (worked out from the relative density of the air - weight and temperature, etc) is then used to determine the correct volume of fuel needed for complete combustion.

The MAF sensor is located at the rear left-hand side of the engine cover and is attached by two torq screws and the wiring unclips from the sensor by depressing the plastic latch in the rectangular clip at the top of the connector (two minute jobbie). If you take it off it should be clean.

Correct.

It might be wise to state how they actually work.  Modern MAFs consist of a very fine wire.  This is heated (it will burn you if you touch it!), by passing a current across the wire, to a pre-determined temperature.  It is the actual 'amount' of current required to get the MAF wire to the said temperature.  Then consider the fact that the MAF is in an 'airflow' - the greater the speed of air - the greater the cooling effect the air has on the MAF wire, and the more current is needed to get the wire upto the correct temp.

Now, considering the job the MAF has to do, and how delicate the fine wire is - it is absolutely vital that the MAF wire is spotlessly clean - which is why MAFs are allways sited after the air filter.  If the air filter element is removed, dirt can collect on the wire, and is then literally 'baked on' the wire - which dramatically reduces its effectiveness.  And if an 'oiled' air filter, such as the dreaded K&N shyte is used - then a microscopically fine mist of oil will build up on the MAF wire - this oil, along with 'solid' dirt (because ALL non-paper filters, including foam and cotton, are categorically NOT efficient at removing 'impurities') - will then bake on to form a solid carbon layer.  Now knowing just how much elbow grease is required to clean off the carbon from your chunky solid exhaust tips - trying to clean it off the MAF will be impossible.

But it is important to also point out - even IF a MAF has a 'build up' on the wire - providing it still physically conducts an electric current - then it will NOT log a fault in the engine ECU.  The ONLY way to determine if the MAF is getting a little 'sluggish' in its operation, is to do some specific live data logging, with either the VAS5052 or VCDS.

Here endeth the lesson . . . .   

[Teutonic_Tamer]

Black smoke assuming its not a diesel would certainly suggest overfueling. whats your mpg?

Not necesserily, the FSI engines are quite smokey.  The exhaust tips on FSI cars are blacker than most modern diesels!

I wouldn't say FSIs are as bad as diesels!  But yes, they are prone to overfueling, and therefore making your exhaust tips blacker than would be expected. 

On a similar note, I was behind an RS4 and when he came off a roundabout he opened the taps... holy crap that threw out a lot of smoke.  I'd have been forgiven for thinking it was a bus!  Of course all that was left WAS the smoke, he was a vanishing dot in the distance 

Aye, had suffered a similar 'sootty' experience in mine a while back.  But with the non-turbo FSI engines, they generally overfuel more to make the 'requested power' - and this is made dramatically worse by using standard unleaded rather than a minimum requrement of 98RON - which only Tesco 99 and Shell V-Power in the UK comply with.

[Velsheda]

Been a while, I know, but finally have an update that I thought I'd share.

So I did as advised and went down to local VW garage. Described the issues and after they'd taken car out for a test drive thought that it was a faulty mechatronics unit (though typically it apparently didn't play up as badly as usual whilst they had it - why is that?). Also they noticed a slight graunching on the steering at full lock, so they would check that as well (and yes, I'd noticed the same thing, but as it was like that from new I just assumed it was normal on the model), so time to sort out the details. NB - after cecking out the exhaust it just seems that I have a slightly smokey engine - there was nothing else wrong that they could find, so I'll just have to clean the exhaust a bit more often going fwd.....

This is when things started to go slightly wrong. The car was a broker import, so I was well aware that there was only a 2 year warranty. But I had my paperwork and knew I therefore had about a month left from 2 years from purchase date. So I was very suprised when after tapping away on his PC the guy said "I'm sorry sir, but the warranty on this car has expired". Much denial and pointing at dates ensued, but unknown to me it transpired that on an import the warranty starts ticking from the date the car is sold at the overseas dealer (even though I am listed as original owner from the later date on all the paperwork). Would have liked to have been told that or had it documented somewhere when originally sold the car

Anyway, without going through all the heated discussions that ensued, I have to say that the dealers were pretty reasonable and fully understood that, paperwork aside, the fact that my DSG unit was within the range that were known to have mechatronics issues, and my front springs were on a list to be changed as well surely bought the SOGA into play, so they agreed to negotiate with VW before we went any further. And about a week later they called up to say VW would pay for all the work (there was a minimal charge of £100 for some reason, but I was happy enough that I couldn't be bothered to argue further). After short wait for parts to be ordered, the car went in last week and I picked it up yesterday.

I'm gobsmacked - feels like a totally different car now, the gearbox must have ben playing up since day 1 & just gotten worse. It's now smoother than the proverbial baby's derriere off the line, and all the changes are soooo much better too. Can't believe I put up with it before. And the steering is much better too - not only is it not graunching, but it feels lighter too (though maybe I'm just imagining that as I'm so happy with the DSG?) 

So, very pleased with the result, and especially happy that the dealers intrvened on my behalf, and happy that VW didn't try pushing it to the courts or whatever.

So now the car is out of warranty, and I checked and as VW replaced the parts for free they don't warranty those separately either. Discussed with the dealer too (the guy in the service area was pretty into his GTi's, so thought why not) and he said they had no issues knowing cars were modded. So I'm going to do some thinking and start off down the modding route....but here's a hypothetical Q to try and give me some ideas....if you had £5k to spend modding a fully loaded (including ICE - already upgraded very similar to Hurdy's set-up) but otherwise stock GTi then what would you spend it on and where? I don't want to do any of the work myself, and would prefer a 1-stop shop if possible. I'm not after bling at all, but rather straight performance upgrades. All ideas welcome!

[Gene Hunt.]

Good news mate,would have cost you a bomb. 

[Alexander]

more ICE!!

Depends what kind of car your after, a remap would probably be first stop then see what you think needs improving when you have the extra power.

[2007GTI]

good to hear you got it all sorted.  what model year is your car?

Been a while, I know, but finally have an update that I thought I'd share.

So I did as advised and went down to local VW garage. Described the issues and after they'd taken car out for a test drive thought that it was a faulty mechatronics unit (though typically it apparently didn't play up as badly as usual whilst they had it - why is that?). Also they noticed a slight graunching on the steering at full lock, so they would check that as well (and yes, I'd noticed the same thing, but as it was like that from new I just assumed it was normal on the model), so time to sort out the details. NB - after cecking out the exhaust it just seems that I have a slightly smokey engine - there was nothing else wrong that they could find, so I'll just have to clean the exhaust a bit more often going fwd.....

This is when things started to go slightly wrong. The car was a broker import, so I was well aware that there was only a 2 year warranty. But I had my paperwork and knew I therefore had about a month left from 2 years from purchase date. So I was very suprised when after tapping away on his PC the guy said "I'm sorry sir, but the warranty on this car has expired". Much denial and pointing at dates ensued, but unknown to me it transpired that on an import the warranty starts ticking from the date the car is sold at the overseas dealer (even though I am listed as original owner from the later date on all the paperwork). Would have liked to have been told that or had it documented somewhere when originally sold the car

Anyway, without going through all the heated discussions that ensued, I have to say that the dealers were pretty reasonable and fully understood that, paperwork aside, the fact that my DSG unit was within the range that were known to have mechatronics issues, and my front springs were on a list to be changed as well surely bought the SOGA into play, so they agreed to negotiate with VW before we went any further. And about a week later they called up to say VW would pay for all the work (there was a minimal charge of £100 for some reason, but I was happy enough that I couldn't be bothered to argue further). After short wait for parts to be ordered, the car went in last week and I picked it up yesterday.

I'm gobsmacked - feels like a totally different car now, the gearbox must have ben playing up since day 1 & just gotten worse. It's now smoother than the proverbial baby's derriere off the line, and all the changes are soooo much better too. Can't believe I put up with it before. And the steering is much better too - not only is it not graunching, but it feels lighter too (though maybe I'm just imagining that as I'm so happy with the DSG?) 

So, very pleased with the result, and especially happy that the dealers intrvened on my behalf, and happy that VW didn't try pushing it to the courts or whatever.

So now the car is out of warranty, and I checked and as VW replaced the parts for free they don't warranty those separately either. Discussed with the dealer too (the guy in the service area was pretty into his GTi's, so thought why not) and he said they had no issues knowing cars were modded. So I'm going to do some thinking and start off down the modding route....but here's a hypothetical Q to try and give me some ideas....if you had £5k to spend modding a fully loaded (including ICE - already upgraded very similar to Hurdy's set-up) but otherwise stock GTi then what would you spend it on and where? I don't want to do any of the work myself, and would prefer a 1-stop shop if possible. I'm not after bling at all, but rather straight performance upgrades. All ideas welcome!

[Velsheda]

57 plate (build date mid 2007)...