boost problem

[d-jimbo]

so basically what is happening is that a whistling sound starts at around 10psi and gets progressively louder/faster until about 22psi where my boost limit is reached. initially this was happening ealier on (limiting to about 15psi), then i added more preload to the wastegate actuator and that got me to where i am now. i have tried simply adding more preload and it has made no difference, the wastegate actuator is now at a point where it is almost fully extended with the wastegate closed (virtually de-wastegated).

there is plenty of fuel going in as it is smoking on full boost. i have also had a good look for boost leaks but cant seem to find any (tried soapy water on the joints with car ticking over method, seems dubious but it was the best i could think of). any ideas about why this might be happening? i am ideally wanting to be around 26psi. any suggestions would be greatly appreciated.

my current setup:
fmic with s/s boost pipes and silicone connectors + adaptors
bosch pump - upped fuel, LDA rotate + nylon washer thing removed
hybrid T2/T25 turbo
s/s straight through turbo back exhaust
plumbed into the compressor housing normally used for wastegate actuator only is a boost gauge, the fuel pump, and an MBC (closed)

cheers,

jim

[strictly_perv]

Have you checked the manifold gaskets?
LDA cap?
Any splits in the boost gauge hoses?

[d-jimbo]

LDA cap is tight like a tiger, no splits in the hoses but the manifold gaskets arent in great condition, could a nackered gasket have this much of an effect?

[strictly_perv]

Never had that problem before but i'd imagine it would TBH.

[mark_airey]

trashed inlet gasket will cause all the boost to fall out of the gaps, the other possibility is the inlet adaptor depending on how you have done it or any join on the Boost pipes TBH

[Dave]

Yeh as Mark said, probably a fubar gasket, get a new metal one!...

could also be a knakkered spring in your actuator letting wastegate open under minimal pressure.

[londondan86]

Abother thing to note is that the soapy water trick wont really work.as the engine needs to be under load to get full boost
Also check the back of your boost gauge

[d-jimbo]

Sweet, thanks a lot guys. I'm using a xantia inlet mani so no adaptor. I didn't think the soapy water would be much good tbh. I'm gonna get a new gasket in there and see if that helps. What should I be checking the back of the boost gauge for?

[strictly_perv]

Sweet, thanks a lot guys. I'm using a xantia inlet mani so no adaptor. I didn't think the soapy water would be much good tbh. I'm gonna get a new gasket in there and see if that helps. What should I be checking the back of the boost gauge for?

To check nothings worked itself loose causing a leak. Best check mine aswel :roll:

[silverzx]

Where are leaks possible from?

- Inlet/Exhaust Manifold
- D-Seal

Curious as although mine boosts fine I'm sure its leaking..

[mark_airey]

Where are leaks possible from?

- Inlet/Exhaust Manifold
- D-Seal

Curious as although mine boosts fine I'm sure its leaking..

Anywhere between the turbo and the engine TBH mate, any join in the boosted pipework is a potential leak!

[d-jimbo]

I was planning on taking the manifold off and sorting it out this weekend but as luck would have it, the engine shat itself this morning and spat a rod out. Strange though cos I wasnt giving it the beans at all really. Anyway, just like Jesus it will be resurrected over the weekend, although with a xantia lump instead.

[mark_airey]

Oh well, at least you don't need to find your boost leak anymore

Good luck with the swap its easy enough to do!

[d-jimbo]

haha! yeah, thank heavens for small mercies eh? as long as it doesnt do the same when i stick the new one in. i should be ok, pretty much got it all disconnected, just never taken the gearbox off before.

it was a bit strange the way it happened, i wasnt thrapin it, it just self destructed. it was a bit rattley/tractorish for a while though, could this be due to too much static advance or maybe worn big/little end bearings do u think?

[londondan86]

haha! yeah, thank heavens for small mercies eh? as long as it doesnt do the same when i stick the new one in. i should be ok, pretty much got it all disconnected, just never taken the gearbox off before.

it was a bit strange the way it happened, i wasnt thrapin it, it just self destructed. it was a bit rattley/tractorish for a while though, could this be due to too much static advance or maybe worn big/little end bearings do u think?

Thats the way they quite often go tbh. But as Mark said, silver lining and all that!!!!!!

[Ricky]

What year is your car, and what mileage? I really need to get a spare engine just incase mine goes soon..

[d-jimbo]

It's a 99 with 100k. Been sounding pretty rough recently though. I would recommend having a backup engine. Apparently the xantia engines have a stronger bottom end. I'm hoping that's the case!

[Ricky]

Yeah they seem to take more abuse. There are all sorts of rumours about what causes them to go, one thing others have said and I have definatly noticed is that most of them are 100k or less miles. Mines on 150k so going OK at the moment! If I had the space I would have another engine, not sure my girlfriend will like an old diesel lump in the kitchen!

[mark_airey]

It's a 99 with 100k. Been sounding pretty rough recently though. I would recommend having a backup engine. Apparently the xantia engines have a stronger bottom end. I'm hoping that's the case!

Xantia engines are just another variation of the XUD9 found in the 306, but as far as I am aware the bottom ends are the same........they are all much of a muchness and it will depends more on how well the engine has been looked after before you got it more than anything TBH

[strictly_perv]

Sorry to hear it. The swaps easy enough though.
I've still got the old 1.8 DT in the garage. I'm wondering whether it will be a stronger engine because the the only difference is the bores have a smaller CC meaning thicker walls.
Ran sweet in my car and i've never heard of the 1.8's chucking rods out.

[Dave]

The 1.8 probably would be a bit more reliable, only because it wont produce as much torque as the 1.9 though. I love how everyone is getting spare engines its awesome, people must be pushing

[d-jimbo]

so ive been stripping the old girl down and found a couple of untoward things. firstly, one of the injectors was charred all over the end so i figured this was just a nackered fire shield? more worrying was the amount of play in the turbo shaft. it hasnt long since been rebuild and has quite a bit of movement :? not sure why this would be

[mark_airey]

The 1.8 probably would be a bit more reliable, only because it wont produce as much torque as the 1.9 though. I love how everyone is getting spare engines its awesome, people must be pushing

Says he with half the county's supply of XUD's stockpiled

so ive been stripping the old girl down and found a couple of untoward things. firstly, one of the injectors was charred all over the end so i figured this was just a nackered fire shield? more worrying was the amount of play in the turbo shaft. it hasnt long since been rebuild and has quite a bit of movement :? not sure why this would be

Yeah if the whole tip is charred then it points to that injector not being sealed properly IMO

A bit of play in a turbo shaft is normal, side to side movement isn't a problem unless its hitting the housing, the slack is taken up by the oil when the car is running, any in and out movement in the shaft though and its buggered!

[d-jimbo]

sweet, thanks a lot for all the help guys. hoping to have her up and running again sometime this week. ive replaced the fire seal on the charred injector so hopefully that should do the trick, checked the turbo and no in and out play.