[woodenspatulas]

HI there,

Been lurking here for a while, but took the plunge as I think I'll need all the help I can get!

Tommorrow we are going to strip down, clean and hopefully fix my OH's Golf mk4 GTTDI 115.

Its running without any boost. Heres what we tried already:

MAF check
Vac pipe renewal
Checked inlet system (found and fixed leak)
Checked SMIC
replaced both valves (n18 iirc and N75)
Used Vagcom to find boost negative deviance
replaced main relay due to poor starting

I think I have now got it down to being:
Turbo VNT's arent working
Actuator is soppy

So as we've never cleaned the intake system, and the cars 130k old, we are going to strip the intake manifold, egr, cooler etc off and clean them out. Then the turbos coming off, being split and cleaned.

We have the weekend to do it and a garage to work in so weathers not going to stop us. My only worries are sheering or breaking bolts, getting the oil line off, and actually splitting and refitting the turbo itself.

Any tips of advice greatly recived!

Oh and great site btw

 

[Seatman]

Lol my mate just had the exact same problem on the exact same car with the exact same engine! It turned out to be the actuator that was gone, take it off and give it a shake, if you hear it flopping about then it's goosed, that's what happened to his and quite common apparently. With regards to the bolts you might be best to just take off the exhaust manifold and turbo together then get it on the bench and soak it with some sort of releasing fluid but I would recommend you just take off the actuator on it's own first, once that's off you can check the lever on the turbo to see if the vnt is sticking or not but it might end up being the actuator and you can get them for about £70 new.

 

[woodenspatulas]

Haha funny you should say that!

Just been under the car and tried moving the actuator when the car was running. Holding it in position for a few seconds and I can hear a change in exhaust, mire noticeable at the back end. Then I can hear the turbo changing note too. I'm certain the vanes aren't stuck!

So I popped the vac hose off the n75 and tried sucking. There was defo a leak. Blowing through it and I can hear a leak coming from the actuator itself. So tomorrow it's coming off.

Funny thing was after I spent a while fiddleing with it we went out to get some curry and it's back boosting again, although not as strongly as it used too.

Wonder how long it will last, but the actuator is coming off for sure!

 

[Seatman]

2x lol, that's also what his car was like, boost coming and going etc til eventually it gave up alltogether. The actuators rust inside around the seal of the diaphram then need replacing.

 

[woodenspatulas]

Just driving about now and I've rigged up the vcds only the free version so I can't log properly but I've found the spec intake pressure is always less than the actual.

The boost goes above the max reading of 2150mbar so when giving it large it just maxes out!

Maf is about right although when off throttle the specified amount is higher than the actual, when accelerating the readings about match.

Torque seems good, 330nm+ from what I've seen

 

[stevieboy]

hello folks, been reading around this forum for ages with what amounts to the same problem.
in ireland i have an 02 Alhambra with the 1.9 115hp tdi vnt and its broken my heart for nearly 3 years.
i have replaced 3 turbos,all the bulkhead actuators(n75 etc),3 new MAFs ,all the vac tubes and much much more. ive had it on computers and got all the usual codes, boost this and deviation that.
just now my brother in law, Mechanic, took it to a Guru who discovered that the boost control sensor is a dud.apparently they can pass thru a standard sensor test and not show a fault code but send out haywire pressure signals as soon as you touch the go pedal. its vital to get the serial right when replacing/testing as even a small diference will give a fault and suggest that its not that sensor at fault.
i have had a lot of success freeing up vnt mechanisms in situ with a home made rod,WD40 and BBQ cleaner. in every instance the turbo has freed up and worked fully afterwards.
i will report back after the latest TLC.

 

[Seatman]

I would never discard a turbo unless I personally had been through it and there was either excessive oil, excessive shaft play or it had split in two, the newer turbos from around 2006 ish seem to be under developed and seem to break a lot but these older ones are usually pretty tough and most of the time it's something else causing the problem.

 

[woodenspatulas]

Well suddenly back to lame car again!
So as soon as I can the actuator is coming off andthe replacement going on.

Fingers crossed that sorts it

 

[woodenspatulas]

Well its been a while.

To update, I eventually changed the actuator as the old one was shot to peices.

Checked the vane movemment and its been fine since...........


...........until now

the boost is suddenly slow to build and it throws the boost negative deviance code up intermitantly.

Im going to try and get under the car asap and check the arm again and the boost pipes etc.

Also got to replace the coolant temp sensor, which I did recently for the MIL's car.

I will update incase it helps anyone.