Did you ever get to the bottom of this because I'm having a similar problem with my 2.0 HDI Xsara?

The loss of power only seems to happen after a short journey in the rain, but tends to last a few days after the rain has dried up. Loss of power and black smoke under load where she is overfuelling are the major symptoms. It is as if the turbo is not working . . .

At the moment I'm steering towards a forum I found where the vacuum pump is sticking, because I also lost most of my brakes a couple of weeks ago whilst driving in the rain - the pedal just went hard! Apparently the vacuum pump is needed to activate the wastegate and allow the turbo to build up pressure.

Let me know if you got to the bottom of it!

James

James,

I relate the following for your information. I cannot see what the wet conditions would have on your problem unless it was ECU related i.e. water in the connections. Under these circumstances, you would surely get an engine management warning light and limp mode. This, or MAF problem would not give you lack of brake assist. That’s got to be servo or vacuum related. It might be you have two different faults, vacuum and engine management.

I have recently experienced problems with the vacuum side of the engine control system of my Xsara 2.0 Hdi. I lost both power in the form of what appeared to be no turbo and loss of braking assist. From my own investigations, the cam driven pump (Pierburg, in my example) is connected via a tough flexible connection and then to a more rigid bulkhead mounted tube to the brake servo. This large bore tube has two small bore take offs to the gas recirculation and turbo controls connected with thick walled flexible tubing and “switched” by Bosch electrovalves under ECU control.

So, first thing I did was to remove and inspect the vacuum pump (reasonable access and straight forward job). This is an impressively engineered device, oil lubricated…little to go wrong. I cleaned it out with petrol. Aside from some wear (my car has covered over 200,000 miles) the only likely problem was some form of blockage in the inlet. I had read that there is a one way valve in this inlet, but could not verify that. There was quite a lot of sooty gunge released by the petrol. After pre-lubricating and reassembly, the pump was re-fitted. For some 200 miles all seemed well ‘till the problem re-occurred. I changed the pump for a new item from Citroen (£100 plus Vat). This did not fix the problem.

So what else? The Citroen service agent took the car in and checked for vacuum leaks on the lines. They found that the EGR (original) was leaking vacuum, so this was changed (be advised, not a DIY job). The car exhibited a useful performance boost due to this change and all was well till a re-occurrence of the problem after a long motorway run.

The agent noticed that the main feed pipe to the servo was being flattened where it rounded the join to the bulkhead connection (only visible once the heat shrunk protective sleeve was removed). This was changed together with two of the thick walled tubes. It was noticed that where these tubes are touching the hot engine, over time they had lost rigidity and were quite easy to squash between the fingers; the new tubes are far too rigid for that. The one that goes underneath to the turbo also showed signs of being trapped where it passed round the cam belt cover. These items are inexpensive from Citroen and straight forward to replace.

Is it fixed yet? My main concern is that I cannot say for sure what is or was causing my problem and without that, only time will tell.

Good luck with your car