Join Date: Jun 2001
Location: Bergerac, France
Alot of my problems have been with the small bore hoses that live around the bulkhead. They apparently go brittle with age so can crack. I have had the hose slip off the absolute pressure sensor as well (small black box on the bulkhead in the middle of the car with small bore hose going into the bottom of it) The large bore hose between the plenum and intercooler could also have a leak, and I would definately get underneath the car to check that the endcaps of the intercooler are intact. These can easily be cracked just by overtightening the jubilee clips!!
If the car is producing 0.6 bar it is very unlikely that you will be able to hear the leak at tickover, which is a shame.
Another place to look is in the chip. Alot of the engine safety measures are controlled from the chip, including limiting the boost, 1st and second gear and also if the intake temp is over a certain value, if you have got a dodgy chip this may be causing boost probs, although I would have thought that it would be making more not less boost.
Have you got the standard chip back in the car yet??
Be careful when you get the boost back, the increase in performance becomes addictive. I just mean't to improve the car a little, but have ended up with a bit of a monster. @265 bhp and 315lbs ft of torque. All in a standard looking car.