Twin Turbo Zero Boost/Not Boosting - But no 66!

[Decimate]

Righteo, so....

Just got my first twin turbo (99 GTB) but by no means my first Subaru, I\'m now experiencing the delight that is the TT system. Just before I go further - yes I have searched first, but my situation seems to be quite odd compared to some of the other TT issues.

Firstly, per the title - there are NO codes on the ECU ... at all, and the check engine has never come on. Basically my \'206kw\' GTB is actually a low compression non turbo .... my Terrano would be quicker. No primary or secondary. When accelerating there is a slight high pitched whine that is speed related but that\'s about it. The car is stock as and really well looked after - 160 odd kms.

So far after hours googling - UKLegacy, NASIOC, RSLiberty etc etc I\'ve tried a few of the first obvious checks - I\'ve taken off all the vacuum hoses one by one and blown/sucked through them whilst listening for leaks or cracks but can\'t find anything. I\'ve also carb cleaned all the solenoids in the BBoD and in the passenger guard, but nothing. I\'ve checked all those vac hoses too.

I\'m basically down to getting ready to pull all the intake etc off and check if the primary is actually spinning, I\'d be very very surprised if one of the turbos has siezed given the general condition of the car through ..... but I was wondering if there are any other suggestions I could try?

Like in this thread: http://www.clubsub.org.nz/forum/index.php/topic,36146.0.html

Could I simply remove the wastegate actuator hose and see if that forces it to boost?

I\'ve also been perusing this thread with similar symptoms http://www.clubsub.org.nz/forum/index.php/topic,5422.0.html

where someones car isn\'t boosting but they get a CEL.

Any suggestions for where to next would be appreciated, in particular if there\'s a way I can \'force\' it to boost? thanks!!!

[kamineko]

lets start with the fuel. running 98?

any change after an ECU reset?

[Marky]

Marky doesnt know much he just types a lot

- do you have a boost gauge on it? is it *actually* not making boost, like does it go to 0 vac and just sit there?

need to rule out if its a mechanical issue or not really, could be chasing solenoids and sh!t when its a siezed turbo or massive intake leak

for what its worth some of them are bastards who refuse to throw CELs despite your best efforts

[Guest]

 Marky said:

Marky doesnt know much he just types a lot

- do you have a boost gauge on it? is it *actually* not making boost, like does it go to 0 vac and just sit there?

need to rule out if its a mechanical issue or not really, could be chasing solenoids and sh!t when its a siezed turbo or massive intake leak

for what its worth some of them are bastards who refuse to throw CELs despite your best efforts

Like 25psi and 7k ae marky

[Marky]

that fixes most problems

[Jord]

+1 on boost gauge to see what its doing.

Have you tried entering the car into diagnostic mode via the green plugs?

Have you checked to see if the system is holding vacuum?

[Johnnynz]

If your in Palmy or Wangas I have an el cheapo boost gauge you can have to check it.

Pm me if location is right

[Decimate]

I have a boost gauge here (thanks for the offer tho Johnny), just haven\'t found long enough vacuum hose yet! But I agree I really do need to test that (although my mind wants to rule that out as it\'s honestly the most sluggish thing you\'ve ever driven).

I\'ve put the green connectors on, get the same result as the black ones - no code, just a steady blink.l Although I swear when they were connected the so9lenoid box started wheezing and sounded like a BOV was repeatedly cycling somewhere.

How do I test it the system is holding vacuum? Is that the spray soapy water test?

[Marky]

the sneezing is normal, it means in all likelihood that it does hold vacuum just fine - youre hearing the system use the vacuum tank to open the exhaust control valve

there are a couple of things it could be, but no point getting hands dirty until the obvious is checked - a jammed primary could explain it, or wastegate stuck wide open. problems with the tt system normally only become an issue with the switchover and/or not switching back and forth, it only has literally 3 components involved

need more info before bothering to internetdiagnose

could be as simple as wastegate solenoid being bung, on 6psi actuator pressure they feel severely sluggish and kinda broken

[resurrection.inc]

Is it a non turbo ?

[Decimate]

 resurrection.inc said:

Is it a non turbo ?

Err .... no.

K Marky I\'ll so some better diagnosing for ya! Keen as for your help and it;s much appreciated

Will get the boost gauge on tomorrow then will take all inlet piping off failing that

[Decimate]

 kamineko said:

lets start with the fuel. running 98?

any change after an ECU reset?

No 98 here in Nelson, otherwise I would. And no change.

So I\'ve had a play this morning (I still don\'t have a boost gauge) and took the intercooler and bits off. I\'m 99% the primary is spinning, it was pushing out a shitload of air at least at 3-4000rpm (in neutral) it is. I checked the turbo -> intercooler pipes and they seem fine, also the wastegate on the primary was shut and I could open/close it with pliers pushing the rod. So at the very least it should be getting boost to the intercooler? So I thought maybe the BOV was leaking - I took off the recirc pipe while my wife pulsed the throttle but no air was going out the BOV.

I couldn\'t see much of the secondary coz of the bloody intake piping but I checked the butterfly valve in the intercooler piping from the secondary and that opened and closed OK once I\'d released the vacuum pressure.

So, if I get a boost gauge and its not reading pressure in the manifold, what could be stealing my boost???

And if it is reading a small amount of pressure, but not enough to spin up the secondary, is it possible still leaking somewhere. And if it\'s reaching the correct amount of boost from the primary, but not performing then could the motor be shagged??

If the latter, again I\'d be surprised as there\'s no symptoms on the oil/water systems.

[Decimate]

I\'ve got the boost gauge connected and it\'s only readying -5 vacuum so probably isn\'t a reliable gauge. I\'ll take it for a \'boost\' later and see what it does.

On another note, I noticed this on the AFM plug wiring - as you can see the green one has been soldered together, and then spliced into what looks like a larger core cable a little further down - could this be causing issues? It looks like an average job at best.

[Decimate]

Talking to myself here

Took it for a whirl with the boost gauge connected, and it does get to 3-4 PSI (but only about -5 vacuum ???)

After winding it up it also threw a check engine 23 (air flow sensor) so combined with the dodgy wiring, we might be getting somewhere.

[acidbath]

yeah that wiring real dodgy and could have shorted out you afm

would be a good idea to replace and probally is your problem

[acidbath]

update? was it your afm and dodgy wiring?

[Decimate]

Should be able to tell you this evening or tomorrow - whilst I was waiting for the new AFM to turn up I pulled the fuel pump to check the sender as the gauge was dodgy and broke one of the plastic pipes : so hopefully new pump will turn up today!

[Decimate]

Well, brand new AFM from Subaru has made a slight improvement but there\'s definitely no boost there still. Will try the ECU next, if that fails then f%&k knows.

[acidbath]

secondary relief valve they are prone to failure mine did but i was getting maybe 5psi, made a funny noise as well like a honk thru the intake when changing gears

[Decimate]

There sounds like a whining noise coming from around the intercooler area as well, not sure if related or not. secondary relief valve - is that the one that sits in the intake track between the two turbos?

[boon]

 Decimate said:

There sounds like a whining noise coming from around the intercooler area as well, not sure if related or not. secondary relief valve - is that the one that sits in the intake track between the two turbos?

Are you sure you don\'t have a mahoooosive boost leak? Although it would probably run like a bag of crap if you did.

Where are you based? I\'m sure someone on here could have a look over it.

[lachlan]

no it is identicle to a blow off valve and its between the 2nd turbo and the air intake

[Marky]

If that is stuck open it will only stop it coming on secondary boost - on primary only it is not pressurised so won\'t matter

Very very simple to diagnose though - just block the hose underneath it and see if problem persists

Main bov being open would do this also, just putting a hand over it and revving it isn\'t much of a test / doesn\'t really rule it out

My suggestion is block the main bov recirc hose, and the secondary one also, see how it goes. Two possible culprits and free to check if they are at fault

[Decimate]

 boon']

[quote name='Decimate said:

There sounds like a whining noise coming from around the intercooler area as well, not sure if related or not. secondary relief valve - is that the one that sits in the intake track between the two turbos?

/quote]

Are you sure you don\'t have a mahoooosive boost leak? Although it would probably run like a bag of crap if you did.

Where are you based? I\'m sure someone on here could have a look over it.

Trust me, it runs like a bag of crap!

And Lachlan yep that\'s the one I was talking about\'

And Marky, when you refer to the secondarys BOV that means the relief valve?

Ill try all this today. I\'ve also got a diagram of where all the hoses go with numbers etc so ill make sure they all match up

[Decimate]

Well, the pipes match, and it\'s not the BOVs.

I\'m going to take every piece of intake piping off and see what the fuck\'s going on.