peteh

iTrader: (3)

Anybody have any ideas what could be wrong a friends golf?

They describe it as being slugish and generally poor performance, they compared it to a passat they went in the other day and said how more pokey the passat felt.

It's a 2000 pd engine model, 6 speed etc etc.

Heard airmass meters get clogged up, but this is just after the air box so find it hard to believe

Any ideas?

cheers

ECU Monitor Enthusiast

iTrader: (1)

Is the engine managment warning light on ?

If not, I would check for a split hose between the turbo and inlet manifold.

As for air mass meter, it makes no difference where it is, it still flows
the same amount of air that the engine consumes !!!

James

no, air flow meters go for a past time, i think they're about £70 from vw. this is the first thing to try really as they do go for a past time.

From there it needs to be plugged in and checked over, n75 boost solenoids do play up, vacuum pipes from that to the wastegate actuator can split and finally turbos do play up alot.

ECU Monitor Enthusiast

iTrader: (1)

James,

My air mass meter comment was in response to this....

I.E. He implied the position made a difference when it doesnt.

Graceland

Have you checked the brake pedal switch - if the ecu thinks that you have your foot on the brakes, it cuts power (as I found out last night in my mates 150bhp Golf GTTDI Anniversary )

peteh

iTrader: (3)

no, no engine light, i had a good look under the bonnet and it's like brand new, it's only done 60k, which is naff all for them, i suppose next thing would to be looking for leaks, but i know a friend had a similar problem and he just changed the air mass meter.

peteh

iTrader: (3)

could you tell me what 'go for a past time' means?

peteh

iTrader: (3)

i just meant, if it was a sensor in the say intercooler to inlet pipe then i could understand it being clogged up, with my diesel or oil, but thought just after the airfilter the air would be super clean

peteh

iTrader: (3)

interesting one

Graceland

The air may well be clean, but if the breather goes to the air filter box, like on most cars thesedays, then it will be sucking in oil vapours aswell and this could possibly clog the MAF sensor too

James

Simon, check the post times

re: going for a past time, as in they fail often and require changing often, 60k miles sounds about right to be honest. i've changed literally hundreds of these on these cars it's a well known problem. Simon, can probably explain much better than me how they actually break but i believe they just burn out?

peteh

iTrader: (3)

arhh ha!

good point mate

SteveB

iTrader: (3)

AFM's are like bloody service items on VW/Audi group cars....

peteh

iTrader: (3)

cheers lads, ill let him know

he keeps asking me 'it's not as fast i thought it was going to be', but then his other (weekend) car is a 348ts ferrari

Rhys

as said, change the MAF always go on VW's

peteh

iTrader: (3)

it's the one just after the air filter isn't it? before i make myself look a wally

James

yes

peteh

iTrader: (3)

ok, bit more info for you, just been across and i told him AFM which he's going to try tom, but also told me something that he didn't tell me before, he said it's like the turbo boosts up for maybe 1000rpm between 2-3k then dies off

actuator maybe?

Lee_R21Turbo

iTrader: (1)

MAF mate - even if its not knackered its worth changing at that milage anyway.

Can you get someone with VAGCOM to do a diagnostics check on it perhaps??

jr

where abouts are you/your mate, as i and a afew mates have vag com and someone may be able to help

i would suggest MAF, or intercooler pipe possible, as they run seals on these which fail

markk

iTrader: (2)

VNT fault pal definatly

strip turbo and clean out vanes

sunny

iTrader: (1)

I get this problem and also drive a 115 gt-tdi. A quick fix (if this is the same problem as mine) when driving and this happens just turn the engine off and start it again and presto we have boost again. Give it a try, sorry its not a proper solution but sorts the problem out in the mean time. Also perhaps this could give others in the know more of an idea?

Sunny.

peteh

iTrader: (3)

Cheers lads, he's had the car put on a vag diagnostic thingy but all said normal

And he's actually trying a different AFM today so that should rule that out, are the turbo's hard to pull apart?

sounds like a hard job

and they are a pig to get at

peteh

iTrader: (3)

what's VNT by the way?

Lee_R21Turbo

iTrader: (1)

Variable Vane thingy - its like you've got two different sized turbos in the one so you get low down power & power stays further up the rev range.

Very much doubt its the VNT tho if its been driven properly all its life & not just like a granny going the shops - mines on 161k & its still on the original turbo with no probs!! But I suppose theres always a first time for everything!!

peteh

iTrader: (3)

so like an S4 audi, they are biturbo aren't they?

peteh

iTrader: (3)

i thought maybe a weak actuator or something, letting the boost out and not going into the engine?

markk

iTrader: (2)

im going to have £50 on this being the turbo,

especially if you can switch it off and then back on and teh car is ok for a short term,
and VAG diag software will say ' turbo/supercharger overboost limit exceeded'

take it off and strip it, you can free off the nozzles.

James

Actuator is controlled by the n75 boost control solenoid.

What happens in VNT [varible nozzle turbo, aka VGT, varible geomentry turbo] it has vanes in side, these open close allowing different amount of flow kinda thing, these are linked by a ring & 3? rollors & then connected to the actuator on the side, so the ecu tells the N75 to work the actuator, the actuator moves the ring inside which moves the vanes.

Now these vanes have very small tolerances, a build up of carbon & rust - as you would expect on a exhaust manifold - results in the vanes siezing in position, this then results in 2 scenarios, 1) over boost & 2) not enough boost. In all cases i've seen a fault code is produced on either occorance, typically boost pressure control limit exceeded. Then then puts the ecu into LOS mode [limp home] key off key on cycle resets the ecu and your away again!

Best way to test is to reach over the back of the turbo and move the actuator, it should move relatively freely, any tight spots or no movement atall indicates a fault inside.

They're not that bad to take off and strip down, but beware oil feed pipes are very fragile, oil returns can also be a problem, thin nosed molegrips work best, the nut on the turbine is a left hand thread and be warned the 6? bolts holding the 2 halfs together can snap, not for the diy mechanic on the drive on a sunday afternoon imho.

Audi S4 bi-turbo is twin turbo and doesn't used VNT, apart from a lancia or something back in the 70's i think only the current 911 turbo uses a VNT on a petrol engine?

ffs another essay

andyt

iTrader: (1)

same prob as my bora mate and belive me its the air mass meter, i took mine to VW garage and they put it on a check and came back with the same thing, any way went to a VW cheapo garage specialist and the man drove it 100 meters down the road came back changed the air mass meter and it was spot on straight away

£65 + exchange for old one fitted

Lee_R21Turbo

iTrader: (1)

If I wasnt as skint as I am at the mo I'd risk having £50 on that its the airflow meter - especially as he doesnt say that he can reset the ignition and it goes away & that he said VAGCOM has come up clear!!!!

markk

iTrader: (2)

LOL unlucky !!

dont always believe what GST's tell you pal, as they donthave all the info