Xsara HDi 110 - intermittent turbo boost

[Will]

Hi All

I have noticed a funny with my Xsara recently. The turbo boost seems to go through phases of being intermittent. Sometimes there is none at all, other times it is back with a vengeance. Often I can actually feel it draining away, as if something is shutting off, as i put my foot down.

Typical scenario - pull put of a junction. Plenty of pull in first. Into second, no discernable boost and you then have to plod your way up through the gears. Sometimes if you ease off or change down boost returns and all is well again. Sometimes it comes back as revs and speed rise. Sometimes it is just fine!

Engine has 107k and is properly serviced etc.

Any ideas as to what to check first wouldd be appreciated.

Many thanks
Will

[nick]

Hi, just noticed this. I still lurk on here from time to time although I now drive a . . . . . . . .Skoda Octavia sorry everyone!

Strange question but do you also find the brake pedal heavy when it's doing this? I had this problem with my previous Xsara HDi, coupled with loss of servo assistance to the brakes. The cause was the vacuum pump intermittently sticking and was cured by taking the pipe connector off the pump and spraying some WD40 in.

The same vac pump supplies both the brake servo and the turbo wastegate on the Xsara 110 so the two problems often go together.