yet another turbo question

[dcburton]

Had a day trip down to Glasgow yesterday (around 370 miles round trip), all fine on the way down but on the way back I thought the car was lacking it's usual "oomph", it's like there is no turbo fitted, not as bad as my naturally asphyxiated ****roen ZX dismal but definitely lacking it's old performance

there has been no bangs, clatters or clouds of smoke just lack of poke noticed when I put the foot down going over the Drumochter pass

car is an '02 plate Octavia Estate 1.9TDI with 170,000 on the clock

David

[mbames]

Several options are possible.

Can you get the fault codes read?

Sticky vanes in the turbo, failing MAF, failing n75 valve, dodgy MAP.

If / when it next feels like it is lacking power try cycling the ignition and see if that brings the power back.

If you can find a long uphill, boot it up there in 2nd/3rd and see if the power seems to drop off, cycle the ignition and then see if it is happy again. If always down on power then it might be the MAF unplug it and see if that brings the power back.

[missingmyvrs]

variable veins on turbo blocked by the sounds of it common problem req turbo to be stripped and cleaned not a hard job and can be done by anyone that can hold a spanner

plenty of info on here

[mbames]

variable veins on turbo blocked by the sounds of it common problem req turbo to be stripped and cleaned not a hard job and can be done by anyone that can hold a spanner

plenty of info on here

Not a hard job, but quite time consuming.... lots of bits to come off - need a nice place to do the work I would suggest, not much fan laying in the street doing it.

[dcburton]

I have no access to a fault code reader without going to somewhere that will charge at least £40/hr for the privilege :(

also, being a newbie to anything with the present style numberplate layout or anything from VAG, I have no idea what MAF, MAP & n75 valves are far less where to find them :S

don't get me wrong, I'm not a total dunce with a spanner, just not up to speed with "modern automotive technology", last timing belt I did was on the old ZX dismal

my background is filling station forecourt repair & maintenance, with a couple of years of hydraulic hoses thrown in for good measure.

[mbames]

Your best bet is to see if you can find a member with VCDS (previously known as VAGCOM) or buy yourself a fault code reader..... they we well worth the investment. Or even a cheapo vagcom cable from ebay and get the shareware version of the VCDS will get you going.

The lower left pipe on the n75 goes to the turbo to control the actuator (moves the vanes) by varying the vacuum, and the MAF (Mass Air Flow) measures the air intake into the car.

MAP = Manifold Absolute Pressure (it is located in the pipework just above the intercooler, near to the windscreen wash bottle (not really accessible unless you remove the headlight).

I suggest you have a search on here for turbo cleaning, it has been well covered in the past by myself others. If nothing else it should help you understand how the variable vane turbo works - I gained most of my knowledge from the guys on here.

[dcburton]

thank you very much mbames, found that same picture while doing a search a wee while ago, went out & located same bits on Oswald. I have taken the car out for a run & the turbo is working as it should again, but has been moved into the "keep an eye on" category

I am hoping it can wait until October when I have a weeks holiday before I resort to stripping it down.

while I was checking under the bonnet I found a small control box cable near the MAF sensor, it had a scotchlock connector attached to one of the MAF wires & anther cable connected into a loom connector, sticker on box says Art. Nr 20007, PBCLM4, quick search brings up a German page referring to golf mkiv, some kind of potentiometer. wil post a pic once I've worked out how

[mbames]

That sounds like a tuning box..... (if the real deal), otherwise it is probably just a resistor in a box!

[lumac999]

Location of MAP sensor FYI although early ones I beleive are located on intercooler pipe higher up and easier to remove.

[mbames]

Location of MAP sensor FYI although early ones I beleive are located on intercooler pipe higher up and easier to remove.

My 2001 110TDI has it's MAP in that location. I had a half-hearted attempt at removing it a while ago, and I could not get a screwdriver at a suitable angle for the left most (wing side) screw.

[lumac999]

My 2001 110TDI has it's MAP in that location. I had a half-hearted attempt at removing it a while ago, and I could not get a screwdriver at a suitable angle for the left most (wing side) screw.

Mine was pretty difficult to get out but you are right about the need to remove the light as with it in situ there's no room.