Driving along the motorway at 80mph, slowed down to let someone into the outside lane, when I put my foot down to get back up to speed there was nothing there

Pulled into the slow lane and gave it a bit more throttle.. nothing just the sound of air escaping.

Anyhow had it trailered back to my mates garage as not sure whats up and poked around under the bonnet. No split hoses, no error codes. So we plugged his computer in and went for a spin.

Gave it a little bit of throttle and it boosted fine, up onto the dual and gave it full throttle and it boosted fine and then suddenly went flat witht he sound of air escaping again. Turbo pressure dropped on the compter but again no codes.

I have had the intercooler and rekated pipework off and all seems fine. No vacumm tubes are off so not sure where to go now.. im thinking either the dump valve (standard) or the intercooler is leaking?

 

Should mention its a 95 turbo wagon auto no major mods other than a Polar performance chip.

Cheers!

 

I think you need to get it pressure tested to be certain where it is coming from. These boost leak problems can be a pain to track down. A friend of mine was quoted £60 for a test on his VW Golf. It turned out to be an intercooler leak and was a pain to change. Luckily they are so much easier on a scoob!

 

Sounds like a plan, I will blank the Dump valve off tommorow, and if that doesn't help I will try and get it pressure rested. Cheers

 

As has been stated, there are lots of pipe/components to the BCS.

But seeing as you've checked all visible pipes, etc., try removing the IC and check it for splitting and, moreover, check its hard plastic intake pipe carefully for splits/cracks too.

Also, it could be the wastegate getting stuck open for whatever reason ...

 

I have had the IC off as that was my fist though. The black plastic pipe cracked last year so was replaced with a samco silicone jobby. as have all the coolant / turbo hoses. Also renewed most of the vacuum hoses at that point.

ALl hoses seem fine, so must be hardware.. wastgate moves as normal, but maybe the boost solenoids full of much and jamed holding it open? Not sure.. Or the DV is dodgey, or the IC is leaking.

I will rule out the DV tonight, and clean the boost solenoid with brake cleaner and go from there!

 

Sorry mate, I overlooked that in your original post

Yeah do that, then if it still persists, suspect the IC for split/s

 

sounds to me like the dump valve is playing up or the boost solenoid. if the intercooler is leaking shove that one i gave you a while ago on!

 

Never got to the bottom of the overboosting with the larger intercooler, especially in the cold

Did the old brake cleaner trick in the boost solenoid and its running fine again I will give it a service in a few weeks and will clean out the vacuum pipes an all.

Cheers all