: Astra 1.7 CDTI overboosting and whistling.

12-10-2011, 11:02
Hello all

I've just part ex'd my boxster in for a 2005 astra 1.7cdti (100). It's only done 50k, but I've got the infamous problem of overboosting - only seems to happen when on the motorway at around 3000 rpm. The orange warning light with the spanner comes on and the car goes into limp home mode - As soon as you switch off and back on it's fine again. I can give it loads of stick round the country lanes and it drives and boosts perfectly.

So far I have already changed the map sensor + ERG..... No difference. I've gotten hold of a boost (vacuum) sensor/solenoid (seems to have many different names - it's about 4 inches long and sits at the bac of the engine on the drivers side and has 2 rubber hosses running into it) which I am going to change over. I also wanted to clean the turbo out (maybe using turbo clean?) as maybe the vanes are sticking. Does anybody have a guide on how to remove the turbo?

Finally, the car does make a rather loud whistling noise when the turbo comes on boost - any idea? Youtube vid below




12-10-2011, 16:50
you need to get the codes,chances are you will get the P0234 fault code as that is the most common,have a look at your turbo pipes and intercooler as you may have a split or a leak,the most common fault is either the map/turbo boost sensor or the turbo itself,another thing to look at is the vacuum pipe where it come out of the vacuum pump,that can split and bring on the EML,this is a few things you can look at