Hi everyone. This is my first post on the forum after about 12 months of lurking and learning!
I'm hoping someone can help me track-down a boost leak on my 2007 2.0 TFSI.
The car is completely standard apart from a Bluefin re-map and had been running perfectly Ok until recently, when the performance dropped away together with a marked increase in fuel consumption. The performance loss was accompanied by a faint hissing as the boost builds and a loss of torque between around 2400rpm (where the boost used to peak) and 3000 rpm. Strangely, as the rpms rise through 3000rpm, the hissing disappears and the car's performance is close to what it was before the problem appeared.
My first thought was 'Diverter Valve' so on the ramps and under the car. Under tray off and .... there's the problem! Leaky joint on the boost pipe immediately before the intercooler (the oily mess around the joint was a bit of a giveaway). Remove pipe, clean everything fastidiously (strangely there was no oil inside the pipes, despite there being oil round the joint where the seal had gone). Fit new seals, test drive - no difference!
Back under the car, remove diverter valve. Old diaphragm type - rev G. Fully expected the diaphragm to be split, but - like new. Clean, refit, test drive - well you can guess the outcome!
As a precaution, I've replaced the rest of the black seals on the boost pipes with the new green ones. The jubilee clips (where fitted) are nice and tight and we know the diverter valve is good as new. But I still have a car with a boost leak because I can hear it and the performance is down accordingly.
Unfortunately, I don't currently have a VCDS (or whatever VAGCOM is called these days) but my generic EOBD test software is showing no recorded faults - helpful these computers!
If anyone can tell me where else I should be looking for a boost leak with the odd symptoms described above, I'd be grateful a million times over. I think I've exhausted the usual suspects and I'm not sure where to look next.
Thanks for reading and thanks in advance if you can help me along.