S40 T4 wastegate actuator

[mikkey850]

Hello all.

Just a quick question. I had read somewhere that with age the actuator arm hole were it goes on to the waste gate can become elongated and you can lose boost.

I went to check mine today (as my t4 is at 137k) to find that my actuator arm is wound all the way in?!

Is this normal? Or will this be making my engine overboost? I don't want to damage my engine. It looks like it's been this way for years (looking at the rust).

Is this normal? Or should I reduce it?

Thanks,

Mike.

[mikkey850]

Here is a photo of what I mean! (sorry about the size, not sure how to make it smaller!)

[Alex121]

Something isn't right there.

You shouldn't be fully wound in to achieve the right amount of boost. The waste gate from fully unwound to fully wound is about 4-5 complete turns IIRC.

You may have a tired diaphragm in the actuator which doesn't hold boost any more. Do you have a boost gauge or any other means of seeing what your pressure is?

[mikkey850]

Thank you Alex121,

I thought something wasn't right there... The car seems to perform about as I would expect it to standard, and doesn't hit "boost cut", I guess it would be a good idea for me to get a boost gauge and investigate this further?

I don't want to blow my engine up unintentionally, how would a t4 perform if the actuator was in good condition but wound full in? I would imagine it would hit a fuel cut or go into limp mode? This looks to have been like this for some time judging by the surface rust!

Thanks,

Mike.

[Alex121]

What T4 do you have? P1? P1.5? P2? What age is it? They all handle over boost differently.

Regardless though, that's wound in too far for all of the phases.

You'd probably be able to get away with buying a new actuator. Volvo don't sell these any more, they come as a part of a brand new turbo, but you can buy one from Forge motorsport that'll do the job.

I'd definitely get a boost gauge plumbed in, I know people hate them but they're pretty crucial for monitoring what you're turbo is doing.

You'll certainly need one before you fit a new actuator as you'll need to adjust it yourself.

[mikkey850]

Thanks for the heads up Alex121,

My S40 is a late PH1 (1999) with the 1.9 litre engine, non vvt I believe!

I was only asking about how one with a intact diaphragm would act to this level of adjustment to try and get a picture of how the engine management would react. And if my car would stop itself blowing up if it is overboosting at the moment? Like I it doesn't seem to be any quicker than it should be?

If anything the boost seems to come on a little late and taper off dramatically as the revs increase!

I will order a boost gauge for setting up purposes for when I get a new actuator! Just brainstorming but could someone have done this to get around a faulty electronic boost controller? I have heard these are common to fail throughout the Volvo turbo petrol range!

Thanks,

Mike.

[mikkey850]

Ok scrap the last part,

ordered a boost gauge today so I can hopefully post my findings on here this weekend!

I have plumbed them in to my other Volvos in the past but always forget which line to tap in to! I'll have a go with the search part of the forum!

I am guessing my actuator is dead, are there any tests I can do to it to prove this? I tried taking the yellow pipe off the boost controller and sucked on it, it seems to hold a vacuum but maybe has a small amount of leakage?

Annoyingly the forge stuff looks pretty expensive! :(

Mike.

[Alex121]

No need to tap into anything.

The most accurate place to get a vacuum reading is unscrewing the nipple on the inlet manifold and plumbing onto that.

I'll upload some pics later.

[Alex121]

Pics for you...

[foeism]

Alex, where did you get that boost gauge from? And is it really that easy to fit?
Sorry if hijacking.

[Alex121]

I got mine on Amazon and yeah it's that easy. One hose onto the inlet, clamp it tight and you're nearly done.

The hardest part is running the hose through suitably without kinks.

I wired up the LED light in the boost gauge to the radio supply using clamp terminals, removed the plastic trim under the steering wheel and the light control unit. I then ran the vacuum hose through the cruise control plug behind the pedals and up through the steering wheel area, behind the light controls and pushed it up the side of the dash in the corner by the windscreen.

Clamp it tight onto the gauge and you're done.

[foeism]

Alex thank you. I will have so many questions.....but will pm you in time, and will now stop hijacking this thread.