need some help,i have a skoda superb 2.5 v6 tdi ellegance tiptronic,2004 with the bdg engine,car has 180,000 with history and till last wednesday ran perfect,my son went to car to move it 10 yards and fired up as normal,little smoke but nothing major but car misfired,i went out in car around an hour later,runs like a bag of ****e,misfire,no power and massive induction noise through air filter on overrun,it has got much better since,almost full power now but doesn't rev as freely as it did i think,been through system with vagcom,nothing!!!2 days ago tried it again after going out in car(gave it some stick)temp loss of power and warning sign saying imissions,workshop,run vagcom and came up with the 00575 inlet manifold pressure-control limit exceeded.been through everything and i mean everything,hoses,egr,flow meter,intercoolers etc etc etc,all seem good,has a intermittent misfire too but the induction noise on overrun is really loud and it doesn't seem to draw enough air through filter box either,serviced car after this issue with no change,i have had vagcom about 6 months but not used it like this before so ran a test whilst car is on tickover and watched some readings for the cylinders and the readings were all over the place-

diff.cyl.3 mg-str -0.71 / diff.cyl.1 mg-str 0 / diff.cyl.6 mg-str -4.08 / diff.cyl.4 mg-str -0.08 / diff.cyl.5 vs cyl.2 mg-str -1.25/

what are the figures telling me,i assume they are flow related but having mechanical injectors where do the readings come from and more importantly what are they telling me!! are they fuel flow/pressure to the injectors if so i assume a high reading is more fuel!!

i have had car to a turbo specialist who say it could be turbo vaines stuck but has its going to be a £400 bill and no guarantee of cure i would rather try to pinpoint it.on an other note i think car may have had similar problem before as it has maybe in the last 18 months or so(i have had car 8 months)its had new

air mass meter,vacuum box so it has had some induction issue at some time but nothing in the service history,car starts and runs,little bit of smoke at tickover sometimes and an intermittant misfire and when on the road if you demand power for say going uphill there is a slight stutter/misfire and then car pulls away fine,any ideas where to look next without gettin into a money pit first,don't mind spending the money but not wasting it on loads of wasted new parts!!!!!!!!!!!!!!!!!!!!!!!!

Edited 5 January, 201115 yr by tots600

For noise it's the snorkel mate, the plastic that pushes down on the airbox and links the tube to the front panel, they only last a couple of pull offs and on before they don't seal anymore.

Edited 9 January, 201115 yr by Supurbia

For noise it's the snorkel mate, the plastic that pushes down on the airbox and links the tube to the front panel, they only last a couple of pull offs and on before they don't seal anymore.

hi mate,thanks for the info but its not the trunking,it still has the noise when this isn't attached,you can rev car without the flow meter being attached and the induction noise is still there

Excessive induction noise could be an inlet valve not sealing on the valve seat. Next time it happens on your drive, stop engine, carry out compression check. Don't forget 180k miles is a lot of miles and that's a lot of soot going into the inlet manifold from EGR. Soot has a nasty habit of getting dislodged and keeping valves off the seat a bit once in a while. Unfortunately the piston run very close to the valves so could strike the valve in this sort of case. Has been known in the past on various diesels - not specifically to yours.

Check th exhaust as well for any signs of oil. Could be a turbo failure.

On yours, as it's common rail, all the injectors are electronic, so what you were reading were individual cylinder fuel trims. In case of loss of compression for whatever reason (for example inlet valve off the seat) that particular cylinder will be running a very high negative fuel trim.

Excessive induction noise could be an inlet valve not sealing on the valve seat. Next time it happens on your drive, stop engine, carry out compression check. Don't forget 180k miles is a lot of miles and that's a lot of soot going into the inlet manifold from EGR. Soot has a nasty habit of getting dislodged and keeping valves off the seat a bit once in a while. Unfortunately the piston run very close to the valves so could strike the valve in this sort of case. Has been known in the past on various diesels - not specifically to yours.

Check th exhaust as well for any signs of oil. Could be a turbo failure.

On yours, as it's common rail, all the injectors are electronic, so what you were reading were individual cylinder fuel trims. In case of loss of compression for whatever reason (for example inlet valve off the seat) that particular cylinder will be running a very high negative fuel trim.

thanks for reply mate,mine isn't common rail,its the old mechanical system injection,have had injectors rebuilt and compression test,all good so looking at turbo as fault me thinks,is there any point in removing turbo and looking to see if there is a problem or is there nothing to see

thanks for reply mate,mine isn't common rail,its the old mechanical system injection,have had injectors rebuilt and compression test,all good so looking at turbo as fault me thinks,is there any point in removing turbo and looking to see if there is a problem or is there nothing to see

Looking over the engine you have the turbo pipe towards the left (drivers side) going into the turbo. Pull this off. Put your finger in (ENGINE OFF !!!!!! KEY OUT OF IGNITION AND IN YOUR POCKET!!! ) and see if the compressor wheel has excessive freeplay in it - just wiggle it side to side. You should not be able to detect hardly any movement there and it should be free to turn if you spin it up.

Anything more than say 1/4 to 1/2 of a mm and you haver a buggered turbo. Also visually check all the blades for any signs of missing blader or chipped ends.

Turbine side is harder to check as pulling exhausts off is a pain.

It is not a massive job removing the turbo unit and sending off to a specialist for a checkup.

I think I have the same problem with my superb but not sure. It's only clocked 49000 km. just got back after driving it for an hour and did about 55km. As I was parking , on acceleration it makes this windy sound from somewhere near the air intake box . Any suggestions what the problem might be ?

Forgot to mention this is the first time it's happened .