1.8T Actuator servicing

[stugee]

I'm still having issues with my 1.8T when coming on to boost.

I've changed the vacuum pipes to silicon, checked the solenoid by putting 6v through it and its fine, regapped the plugs and changed the coil packs (which made a significant difference).

But when I'm in say 3rd gear and plant the foot, the turbos spools up nicely and then it hits 4k rpm there is a small "chirp" and a noticible decrease in acceleration. If I am very gradual on the throttle input it seems better but there is still something amiss.

There was mention on other threads about stripping the actuator and cleaning and greasing the rod. Being new to turbos, does anyone have a step by step or pictures of the bit I've to service? Does the turbo need to be removed?

Cheers
Stuart

[Lovel]

I'm still having issues with my 1.8T when coming on to boost.

I've changed the vacuum pipes to silicon, checked the solenoid by putting 6v through it and its fine, regapped the plugs and changed the coil packs (which made a significant difference).

But when I'm in say 3rd gear and plant the foot, the turbos spools up nicely and then it hits 4k rpm there is a small "chirp" and a noticible decrease in acceleration. If I am very gradual on the throttle input it seems better but there is still something amiss.

There was mention on other threads about stripping the actuator and cleaning and greasing the rod. Being new to turbos, does anyone have a step by step or pictures of the bit I've to service? Does the turbo need to be removed?

Cheers
Stuart


The actuator is not serviceable.

The actuator rod that connects to the dump valve can be cleaned up if it has siezed onto the waste gate lever once you remove the circlip.

Once you remove the circlip you can check for full movement of the waste gate lever.

If you have a small pressure scale pump you could function the actuator in situ and check it works within it's tolerances.

open 1mm = 0.42 Bar
open 5mm = 0.75 Bar

The actuator is rivetted to the turbo housing so would be a pain to remove insitu.

[stugee]

I've been advised to bypass the boost solenoid by connecting the actuator direct to the turbo housing.

What does this actually do and will it cause any short term harm. I'm assuming it is to determine if the boost solenoid is faulty?

Cheers

[stugee]

Anyone? Don't want to do it unless I can be sure no damage will be caused!

[sraddave]

Anyone? Don't want to do it unless I can be sure no damage will be caused!

I did it and it caused no damage whatsoever. Just diagnosed my fault. So i fitted a manuall controller. Now all is fixed

[stugee]

I did it and it caused no damage whatsoever. Just diagnosed my fault. So i fitted a manuall controller. Now all is fixed

Cheers bud, some people responded to my posts before the outage but all the responses were lost :(

Will get on it tonight or tomorrow! ;)

[sraddave]

Cheers bud, some people responded to my posts before the outage but all the responses were lost :(

Will get on it tonight or tomorrow! ;)

Its a two minuite job...nice and easy

[stugee]

Well I bypassed the solenoid by placing a piece of smaller bore pipe in its place.

The car seemed down on power but more linear with not violent power losses. I also noticed that the very prominent turbo whistle that starts at about 2.5k revs was gone.

Does the above point to a faulty solenoid? Just want to make sure before I spunk £40 on a new one!

[Craig parker]

My 1.8t has that turbo spool noise at 2.5k revs aswel, how can the solenoid cause this noise?? I thought the noise was just the sound of the turbo working? Should there be no turbo noise at all then?

Let me know how you get on buddy

Regards

Craig

[silverdel]

Well I bypassed the solenoid by placing a piece of smaller bore pipe in its place.

The car seemed down on power but more linear with not violent power losses. I also noticed that the very prominent turbo whistle that starts at about 2.5k revs was gone.

Does the above point to a faulty solenoid? Just want to make sure before I spunk £40 on a new one!
By bypassing the solenoid you are just relying on your foot, ie the accelerator, from the explanation I was given the solenoid just delays the "cut in " of the turbo to around 2500 rpm, where as by passing the solenoid effectively lets the turbo come into play at around 1500 rpm, by bypassing the solenoid you eliminate the time lag.

[sraddave]

By bypassing the solenoid you are just relying on your foot, ie the accelerator, from the explanation I was given the solenoid just delays the "cut in " of the turbo to around 2500 rpm, where as by passing the solenoid effectively lets the turbo come into play at around 1500 rpm, by bypassing the solenoid you eliminate the time lag.

By bypassing the solinoid the waste gate will open earlyer as its opened by turbo pressure, it should be down on power as the turbo is not building up its intended psi. Manu all boost controller is 15 pounds off eBay and works a treat on my 1.8t

[stugee]

By bypassing the solinoid the waste gate will open earlyer as its opened by turbo pressure, it should be down on power as the turbo is not building up its intended psi. Manu all boost controller is 15 pounds off eBay and works a treat on my 1.8t

How did you set the correct pressure on the manual controller, are you running a boost gauge?

[stugee]

My 1.8t has that turbo spool noise at 2.5k revs aswel, how can the solenoid cause this noise?? I thought the noise was just the sound of the turbo working? Should there be no turbo noise at all then?

Let me know how you get on buddy

Regards

Craig

My noise is pretty loud, if in second and hit boost, generally people start lookiong to see where the noise is coming from :D

But there was no noise when I bypassed the solenoid. I like the noise but I'd prefer a smooth power delivery. Was hoping that these symptoms would give someone more knowledgeable than myself a better clue to the issue!

[sraddave]

My noise is pretty loud, if in second and hit boost, generally people start lookiong to see where the noise is coming from :D

But there was no noise when I bypassed the solenoid. I like the noise but I'd prefer a smooth power delivery. Was hoping that these symptoms would give someone more knowledgeable than myself a better clue to the issue!

Perhaps you have a hole in the intercooler/pipes

[stugee]

Perhaps you have a hole in the intercooler/pipes

Thats a prime example of the problem. It could possibly be, but buying the £40 solenoid ain't going to fix it and and I'd be wasting another £40. But then why would it stop doing it when the solenoid was bypassed? :banghead:

[sraddave]

Thats a prime example of the problem. It could possibly be, but buying the £40 solenoid ain't going to fix it and and I'd be wasting another £40. But then why would it stop doing it when the solenoid was bypassed? :banghead:

Put a manu all one on it, there only cheap , if you lose 15 pounds it not the end of the world

[Synchromesh]

Have you confirmed that the pivot point where the actuator rod joins the wastegate lever is not seized?

[stugee]

Have you confirmed that the pivot point where the actuator rod joins the wastegate lever is not seized?

Not yet, waiting on a friend letting me use his ramps to check. The car ran fine (albeit down on power) when the solenoid was disconnected, would the problem not persist if it were the actuator rod?

[sraddave]

Have you confirmed that the pivot point where the actuator rod joins the wastegate lever is not seized?

If waste gate was seized it would make no difference when he joined pipes, but it did so I'd say waste gate is working

[Synchromesh]

Not yet, waiting on a friend letting me use his ramps to check. The car ran fine (albeit down on power) when the solenoid was disconnected, would the problem not persist if it were the actuator rod?

When mine was seized the car pulled really well until it hit 4000rpm then the ignition cut out. Overboost pressure operated switch that cuts ignition LT supply. Revs dropped, ignition cut in and engine pulled to 4000rpm again. The cycle kept repeating and it was impossible to drive through it. If yours drives through 4000rpm your wastegate pivot is not jammed. This does assume you have not bypassed the pressure switch.

[sraddave]

When mine was seized the car pulled really well until it hit 4000rpm then the ignition cut out. Overboost pressure operated switch that cuts ignition LT supply. Revs dropped, ignition cut in and engine pulled to 4000rpm again. The cycle kept repeating and it was impossible to drive through it. If yours drives through 4000rpm your wastegate pivot is not jammed. This does assume you have not bypassed the pressure switch.

Is it possible to bypass the intake pressure switch so we can run higher boost?

[stugee]

When mine was seized the car pulled really well until it hit 4000rpm then the ignition cut out. Overboost pressure operated switch that cuts ignition LT supply. Revs dropped, ignition cut in and engine pulled to 4000rpm again. The cycle kept repeating and it was impossible to drive through it. If yours drives through 4000rpm your wastegate pivot is not jammed. This does assume you have not bypassed the pressure switch.

If I'm gentle with the pedal it will go past 4k rpm, however if I put my foot to the floor at say 2k, once it hits four there is a violent cut.

When I bypassed the solenoid the turbo wouldn't cut when driven hard, but if the turbo couldn't build up the same pressure then it wouldn't overboost.

From underneath I can see the rod from the actuator running from left to right with a circlip on the RHS. Do I just remove the circlip and manually move the rod back and forth to ensure its not stuck?

[sraddave]

If I'm gentle with the pedal it will go past 4k rpm, however if I put my foot to the floor at say 2k, once it hits four there is a violent cut.

When I bypassed the solenoid the turbo wouldn't cut when driven hard, but if the turbo couldn't build up the same pressure then it wouldn't overboost.

From underneath I can see the rod from the actuator running from left to right with a circlip on the RHS. Do I just remove the circlip and manually move the rod back and forth to ensure its not stuck?
Yes but i doubt it is stuck as linking the pipes cured the problem.. This means the wastegate is working

[Synchromesh]

Is it possible to bypass the intake pressure switch so we can run higher boost?

When everything is working normally the waste gate would open so the boost pressure would limit so the ignition cutout switch would not operate. Consequently bypassing the ignition cutout switch would not increase boost pressure, it would just disable the engine protection should a future fault result in over boost.

[Synchromesh]

If I'm gentle with the pedal it will go past 4k rpm, however if I put my foot to the floor at say 2k, once it hits four there is a violent cut.

When I bypassed the solenoid the turbo wouldn't cut when driven hard, but if the turbo couldn't build up the same pressure then it wouldn't overboost.

From underneath I can see the rod from the actuator running from left to right with a circlip on the RHS. Do I just remove the circlip and manually move the rod back and forth to ensure its not stuck?

It was a few years ago. I don't think I tried gentle throttle pressure to see if I could get past 4000rpm. From under the car (use good axle stands or blocks to support the car) it is easy to lever off the clip with a screwdriver and then see if the link will lift off the waste gate lever. Mine was solid. I can't remember how I got it off. Probably WD40 and persistence. I cleaned the pin on the waste gate lever and I cleaned the hole in the end of the link then applied a high temperature anti seize spray before I reassembled. After that I pulled the actuator pipe off the pressure switch once a month and applied a few psi to the actuator a few times with an electric air pump to exercise the actuator and hence the waste gate pivot. The alternative is to exercise it with your right foot but that costs a fortune in petrol!

[sraddave]

When everything is working normally the waste gate would open so the boost pressure would limit so the ignition cutout switch would not operate. Consequently bypassing the ignition cutout switch would not increase boost pressure, it would just disable the engine protection should a future fault result in over boost.

Yes but I have a manuall boost controller

[Alan.F]

My noise is pretty loud, if in second and hit boost, generally people start lookiong to see where the noise is coming from :D

But there was no noise when I bypassed the solenoid. I like the noise but I'd prefer a smooth power delivery. Was hoping that these symptoms would give someone more knowledgeable than myself a better clue to the issue!


Mine was making this noise it turned out that the nuts had come loose where it bolts to exhaust manifold