Chasing a boost leak

[jt racing]

Hi all.
Have a 97 t5 and have recently got an absolute ecu. After doing a stage 0 including new timing belts and all that i went to up the boost. After adjusting it at the wastegate i can only get it to halfway on the factory gauge. So i got and mbc and no matter how i adjusted it, no improvement. So i have removed that again and am back to the bcs so am suspecting a boost leak. The little one hidden under the inlet manifold looks to be new but the rest of the pipes look original so am going to replace those tomorrow with the 4mm fuel hose but after moving the airbox this evening i found this. It attaches to the bottom of the air intake pipe. What should it be attached to and could this be causing it?
http://i774.photobucket.com/albums/yy29/jtoftphoto/volvo1.jpg
http://i774.photobucket.com/albums/yy29/jtoftphoto/volvo.jpg

[princepugh]

So, it's coming off the vac tree? If so, I'm sure someone on here should be able to provide a diagram and information. Don't know the 850 very well but wondering if it's PCV related and someone has modified it to vent to the atmosphere instead of back around to the intake?

[96T5Andy]

see this post for a diagram of hoses between bcs, turbo and air intake about halfway down the page.

http://www.vpcuk.org/forums/showthread.php?t=16823

sorry if thats no help, thats probably not what your after if your talking about that large pipe

[p fandango]

its been that long since i binned the original airbox & intake pipe i can't remember seeing a pipe like that, certainly not anything attaching to the bottom of the box itself

it will be having some bad effect on the engine tho as its letting unmetered air in after the MAF sensor

[jt racing]

Don't think thats the vac tree. Isn't that at the front of the block? Thanks tho!

[princepugh]

The vac tree is (from memory) at the bottom of the intake pipe, in close proximity to the turbo so looks right from the picture.

Assume from the photo that someone has actually capped the hose?

[jt racing]

Yes, someone has but a big bolt into it to cap it.

[p fandango]

the vac tree is on the end of the inlet manifold, under the throttle wheel cover

[jt racing]

Thats what i thought. So this isn't going into it then. Could it be something to do with the cruise control? As that doesn't work.

[p fandango]

part of the cruise control is under the airbox, & it does use pneumtics so you could be right there. BT didn't have cruise control so that could explain why i don't remember the pipe (or it could just be my 5hit memory lol)

[jt racing]

Thought as much, although i have the airbox and can't see where it goes on that, ut saying that, it might not be the cars original airbox.

[p fandango]

Thought as much, although i have the airbox and can't see where it goes on that, ut saying that, it might not be the cars original airbox.
BT defo didn't have any other pipes going to the airbox except the main inlet & outlet pipes

[jt racing]

Maybe it doesn't go to the airbox so, maybe it was just hidden over there.

[claymore]

I think I'd be looking at the main boost pipes and intercooler.

[jt racing]

Yeah. Would i pressure test the cooler like a rad to see if its leaking?

[jt racing]

Ok. Have just done the bcs pipes, and the red stripe one that goes into the front of the manifold. Also the one that goes into the fuel regulator. Still the same.
Just a thought though, does the car reduce boost if it thinks is empty on fuel. The reason i ask, is that the fuel gauge isn't working and i know on hondas when the tank is very low, it doesn't allow you to go into the vtec mode.

[jt racing]

Ok. Pressurised the system at the intake pipe just after the maf and after spraying everywhere with soapy water, the boost tree was blowing bubbles off one of the blanked nipples. I say blanked, some twit has put in a self tapper. So i got some gasket sealer and put it round the screw and put it back in. A bit cleaner pulling up the rev range more so from 5k but still only halfway on the gauge. Now i have a new tree ordered but will this leak be causing this much pressure lose? Also have another intercooler on the way just in case. Could hear any leak on the cooler and the pipe behind the inlet manifold didn't leak either.

[T5hug]

hi mate,

Ive just been replacing all my pipework too, The pipe in your picture going into the inlet comes from the PCV (oil tank thingy) its just a breather so shouldnt be causing a leak. I know this doesn't solve your problem but at least you know what the pipes for!!

EDIT: Dont mean to be cheeky but are you sure when you adjusted the wastegate actuator you done it the right way? It could now be held open stopping you getting full boost?!?! Just a thought.

[jt racing]

Not cheeky at all mate. Was thinking that and wound it back a bit and found more go beyond 5k. So suspected a faulty gauge now.
I put the new tree on tonight and fitted the mbc again, gauge is still the same, so am going to fit the aftermarket one over the weekend. Got 'involved' with an evo 5 this evening after this and he went nowhere. So maybe shes boosting better than i think.

[T5hug]

Could it be a dodgy spring in the actuator?

I think if your hoses are ok and vacum leaks fixed the only real simple problems could be the actuator or the BCS (lets not mention wrecked turbo!). Still not up to speed on the T5's yet but a lot of cars have an actuator that will be set to say 5psi and its the BCS that bleeds off air to allow you to boost to say 10psi before sending the air to the actuator. You can remove the standard BCS and replace with a manual controller which would rule that one out. If its still not right then probably a dodgy actuator.

It just seems strange this has only started after your recent work.

Just been going through all this to get mine running nice again! It was boosting too well though and bust a CV joint before i could get it in for its MOT retest!! :doh:

Good luck though! I think the standard guages are pretty reliable! Have you checked you dont have a leak in your hose to the guage!?!

[jt racing]

The hose is to the gauge is fine, so i am starting to suspect the actuator. Will price one up.
Thanks man.

[T5hug]

The hose is to the gauge is fine, so i am starting to suspect the actuator. Will price one up.
Thanks man.

When using the MBC did you replace the standard solenoid or between solenoid and actuator?

[t5lover]

i had the same prob and found it to be the inlet pipe were there the idle control vavle goes had a split around the hose double check all the boost pipes mate your never know u might just find it :)

[jt racing]

Kinda annoyed with this... But i will persevere!!!

[T5hug]

Kinda annoyed with this... But i will persevere!!!

Have you checked with a gauge yet just to make sure you have a leak!?!

[jt racing]

No... been mental busy this week fixing a friends bloody m3...and still waiting for the intercooler to arrive. Will crack into it tomorrow.