Boost problem

[gmogle]

Thought I\'d better stick it on a new post rather than buried in my other.

Right, been out again waking up the neighbours lol it seems that if I accelerate hard into the 2nd turbo (it is boosting 0.8-0.9 on boost gauge) then let off and put my foot back on the accelerator it only makes the 0.4 boost and then letting off again produces this weird air pressure noise. If I let the revs reach 3000rpm and then accelerate it seems fine.

I have tried fiddling with the boost controller settings, turning the balance up and down to see if this made a difference but no although I get better response when the balance is above 50%.

Also then tried fiddling with the boost settings, this was the high one and even if I turn it all the way down it still makes the same 0.8-0.9 bar boost. Now I would have expected to see this be lower if I\'d set it lower ?

Forgive me if I am being dumb here but please help. Want to understand if its the boost controller first before I start on the vac hoses under the inlet plenum. Is it likely to be the boost controller ? If I sitch the boost controller off the car makes 0.5 but makes the funny noise again when accelerating hard and lifting off and on and off in the 2nd turbo phase.

Help, any ideas please, my pride and joy is becoming my nightmare !!!

Cheers,
Gareth

[dj_dee99]

Not that it\'s any help, but I occasionally get a similar problem. On acceleration, the boost seems to stick around 0.35 to 0.40, when I take my foot off the accelerator, there is a sort of "Wooooooooo" sound, then it\'s o.k!

[MarxMcrae]

Hi, I too have the same problem, i\'ve spoken to two people about it and they both said different things.
Firstly I was told that at the back of the turbo\'s there is a Y piece of piping, at the end of that there is a "butterfly Valve" the first person I spoke to said that this is sticking closed once the second turbo has kicked in. He reccommended replacing it.
I then spoke to Pip at WGT and he said that, "yes it maybe sticking open but it is a faulty boost solanoid that is causing the problem and that he could send me one for £20
Personally I trust Pip and intend to get a new solanoid from him, but am also going to change the valve as well just to be sure!!

Hope this helps, any probs give Pip a ring, he\'s always been relly helpful with me!

Marx

[Martiny]

I have a similar symptom, but I have to switch the car off, start the engine again, and then it works again.

[nikp]

I have a similar symptom, but I have to switch the car off, start the engine again, and then it works again.

I had a problem a bit like that - The first time i boosted it, it would go to 0.7 bar (The correct amount) then subsequently it would only ever do 0.5 bar. If i then turned the ignition off, and bump started the engine, it would boost to 0.7bar again, and then back to 0.5. I couldn\'t figure out what the issue was at all, so i took it to Pip, he told me that all the vacuum hoses were \'wired\' up wronlgy.

[gsb876]

Deffo sounds like a vaccum problem somewhere, check all pipes and hoses to see if theres either a hole or a hose support might have stretched over time ?

[strange_days_uk]

Could be that the recirc valve or BOV whichever you have is sticking open for a short while ?

That could be caused by a dodgy return spring, or leaking pressure hose somewhere.