Check the routing of the pipe which goes across the rear of the underside of the bonnet to the jets. I put the pipe in the 'tidy' clip at the lefthand side, looking from the front of the car, and it stopped working. I think the pipe kinks if it is awkward.
The way I found this out was I tried it with the bonnet up, and it worked, while with the bonnet down it didn't.
psic88
June 2009