I did remove the actuator and connect it directly to my mityvac and there was no movement on applying plenty of vacuum,the only movement I got was by putting pressure on(the opposite of vacuum)and the arm moved outwards 6mm.I will look for a new actuator and try and find a diagram/photo/video of how my turbo actuator should work,when I was under the car with the actuator removed I could easily move the part that connects to the vanes(it was very easy to move with one finger but only in the direction as if the actuator arm was pushing outwards.

Sounds like the spring might have failed in the actuator in that case (if pressure caused it to move that might suggest the diaphragm is ok).

hold on right there!! yours is an early 90BHP engine yea? in which case it will have a wastegated turbo not a vnt, so your actuator will be a pressure one not vacuum in which case its working ok as it is and there is another problem causing your lack of boost.

felicia16v may well be right. Everyone has based their answer on you asking about the vane actuator. If your turbo is a non-VNT, it has no vanes - it has a simple wastegate. If this is the case, you can ignore all the posts that refer to VNT turbos.

It is easy to tell them apart from the configuration of the actuator.

Here are some pics...

VNT

non-VNT - simple wastegate

A haaa(as Alan Partridge would say) its that eureka moment when ever thing starts to become clear,I had a problem last year(turbo worked then it didn't then it did etc) and sticky vanes were mentioned but after vag com testing it turned out to be a MAF fault and a new MAF sorted the problem and the turbo was great.So I have always thought I had a variable vane turbo but it hasn't the actuator in the middle it is to one side and it moves outwards(the arm under pressure)so thanks i knew there was something odd all the time.

A haaa(as Alan Partridge would say) its that eureka moment when ever thing starts to become clear,I had a problem last year(turbo worked then it didn't then it did etc) and sticky vanes were mentioned but after vag com testing it turned out to be a MAF fault and a new MAF sorted the problem and the turbo was great.So I have always thought I had a variable vane turbo but it hasn't the actuator in the middle it is to one side and it moves outwards(the arm under pressure)so thanks i knew there was something odd all the time.

Where do I go from here is my turbo blown,no black smoke car runs ok gets up to 70mph on a flat road does have some acceleration but lacks that turbo umph(which was never great but could accelerate up hills)any ideas,The turbo was working ok then stopped and I found the pipe from the N75 valve had broken off and have since replaced all vacuum pipes to N75 and N18 valves.It does take some effort to move the wastegate arm,when it was off the car I couldn't pull the arm out by hand it needed a strong pumping with my mityvac(using it as a pressure pump not vacuum)If I only have a wastegate the turbo should still work as I understand the wastegate is a saftey device to stop over boost?is my turbo knakered?any ideas?

I have just thought my car did run great before it died,it was very quick,quicker than ever then it died(pipe come off actuator)so did I kill it,with the pipe off the waste gate actuator did I over boost and as the waste gate could not work the turbo over spun and burned out?

I wouldn't have thought you killed the turbo, the ecu should have stepped in killed the power if an overboost occurred and if the bearings were shot it should make a nasty noise or put out blue smoke.

Therefore I wonder if the N75 is duff, or it could be the MAF again.

the N75 failing could make the boost low but not by much, I would get someone with VCDS to do some measuring block readings and see what is happening (or not happening)

could be MAF or dodgy boost sensor (maybe killed by not having a pipe to the wastegate?) but its all guesses till it get plugged in really

ok I will find a friend with vag com.I have tried a new MAF but still the same.I have replaced the N75 but with a second hand one so it could be duff?

I still can't work out if the waste gate actuator needs a vacuum or pressure.If it is broken then I would assume(no pressure or vacuum) it would be in the "open" wastegate position meaning no turbo power as exhaust gas is diverted through the waste gate and not driving the turbo ?So if it needs pressure the N75 would pressurise it when the engine is running meaning the waste gate is shut giving max power to turbo,if the pipe breaks off the waste gate diaphram pressure is lost

http://img.photobucket.com/albums/v719/simon7030/DSCF7541.jpg

http://img.photobucket.com/albums/v719/simon7030/DSCF7542.jpg

http://img.photobucket.com/albums/v719/simon7030/DSCF7543.jpg

http://img.photobucket.com/albums/v719/simon7030/DSCF7544.jpg

I have found these photos of a Garrett GT15 Turbo like mine.

As you can see the actuator arm is pulled in to the body closing the wastegate valve,As pressure is applied from the N75 valve(controlled by the ecu)the arm extends opening the wastegate valve to release excess pressure to avoid over boost.So either I have a fault that will not supply the needed pressure to the wastegate or the wastegate is bust as it does require a lot of effort to make it move(cant do it by hand off the car and requires a hefty pumping with a mityvac(using the pump side not the vacuum side)

Edited 20 June, 201115 yr by simon7030

what air pressure does the mity say its supplying when the wastegate starts to move? I think from memory it should be about 12psi (its been a while tho), the spring in the diaphram keeps the waste gate closed untill the required boost pressure overcomes it and opens the wastegate so no pipe = lots of boost as nothing to force the wastegate open against the spring, why not tee the mityvac into the actuator pipe so you can see what pressure it is going to it (use it as a boost gauge).

Ok I have rule dout turbo being a problem,I think I can hear it spooling(running up)The waste gate should be closed and only opens when boost pressure is too high.I am not getting enough pressure to do anything.I have cleaned a the injectors by running

Liqui Moly Diesel Purge neat into the injector pump and it has made no difference.I have cleaned as best I can the AGR flap and valve and tested it with my vacuum pump and the valve that opens to re ciculates the waste exhaust gas gas opens ok and does not stick open.I have cleaned my re usable air filter and yested the MAF again with my limited vag com and that is ok.I have listened to the injectors with a screw driver and they seem to be clicking ok,the only thing I can find on vag-com is the injector tolerance should be -2 to +2 (can't remember the units)injector 3 is +1.88 and doesn't move while the other readings show - amounts so perhaps the injector is not performing as the engine runs still like it has no power up a hill like a petrol engine running on 3 cylinders will go put no acceleration etc.How do I find a member on this forum with a full vag-com system and can use it or should I go to a main dealer for further test?I am trying to buy a compression tester as it has been suggested as I run on veg oil I may have a stuck piston ring and have low compression?

Latest update is that the injectors have been cleaned with Parrafin by a diesel shop and it runs much smother but still no acceleration,the garage say pump has had it as number 2 injector supply just dribbles out where as the others spurt out when nut on pipe connecting to each injector is loosend.There are pumps on ebay but how to I match mine up?Bosch 029 98 250 33 B can't find any information off web to decifer code/part number?

Today is the day I get a new Diesel pump fitted,bought off ebay £150 fully reconditioned.After months of searching the net I have found a reference site to find out what Diesel pumps fit what cars

http://www.dieseljones.co.uk/

The new pump has a VW code 0 460 404 977 stamped on it so look up skoda/octavia on this site under diesel pump tab and up comes the information,type of engine year etc etc Will update outcome of pump fitting fingers crossed.

Got my car back from Garage £144 fitting cost for new/recon diesel pump car runs a little better has a bit more acceleration still won't do over 60 mph on the flat and struggles up hill goes down to 30/40mph.Car runs better with MAF disconnected!I now have a car with the same problem with a new cambelt kit clean injectors and a recon diesel pump total cost just over £500.Next step is to buy another MAF and if that doesn't work I will get a bus pass!

where are you as I could take a look at it and check everything for you?? we have a couple of cars breaking too so could swap bits over to try instead of buying parts to guess at fixing it

Got my car back from Garage £144 fitting cost for new/recon diesel pump car runs a little better has a bit more acceleration still won't do over 60 mph on the flat and struggles up hill goes down to 30/40mph.Car runs better with MAF disconnected!I now have a car with the same problem with a new cambelt kit clean injectors and a recon diesel pump total cost just over £500.Next step is to buy another MAF and if that doesn't work I will get a bus pass!

That certainly sounds like your MAF is dodgy - have you checked what the MAF is reading with VAGCOM?

Also are you sure that the timing is correct, if the belt was changed and the timing was out, it might still be out.

I also work on the theory of changing the cheapest parts first (but I am tight)

Had timing checked with local Briskoda member and timing is way out,on the graph it is way below the bottom line(Blue from memory and well retarded)so I need to alter the diesel pump.I took the timing belt cover off last night but can't see how the 3 bolts can be loosend to rotate the pump as the slots in the sprocket that drives the pump don't seem inline,so I can't see how to adjust it?I live South Birmingham near Lonbridge/Rubery.

Ps the garage that fitted the pump did the timing manually They didn't use vcds or a dial test indicator.

PS I did fit a new MAF works fine showing correct results on vcds.

Bought vcds and set timing spot on very easy to do,car still runs badly with MAF connected,runs very well with it unplugged but slowa dramatically going up hill,bought a new MAF but still the same results,vcds log shows the MAF is ok at low revs ie actual MAF reading matches requested MAF but on acceleration the actual MAF doesnt follow the requestd MAF,Have sent back the maf and had a nother one but still the same results?Can the second MAF be faulty?

Faulty wiring to the MAF maybe, inducing a higher resistance or something - maybe due to a poor connection?

check the brown earth wires that go the the body under/next to the battery you might find them corroded and the copper wire gone green. these earth wires are for the engine sensors and if they get a poor connection they can cause all sorts of funny faults.

trim some of the plastic covering back from the wires to check they haven't corroded , if they have then they need chopping back to good wire and remaking with fresh wire and terminals..

I've seen a lot of this lately at work and they cause quite a range of different problems.