bailey1

iTrader: (2)

hi all having a mare with a 09 mk2 focus rs just wont boost clean it seems to hesitate while under load I cant confirm it as a misfire or lack of power or a hesitation its hard to explain it blew a boost hose then ran awful I replaced all boost hoses as were knackered and the map sensor in the intercooler was broken so replaced that as well its had a new air flow sensor plugs and coil packs and still fault remains next on the list is the boost pressure sensor on the turbo or actuator etc but just wondered if anyone else has had this before ?? its running 400bhp (jam sport )conversion so map injectors exhaust intercooler etc.any help would be great before I have to get in on the rollers and see!!

RichieST

iTrader: (2)

Not too sure if it shares the same part with the st, but the boost control solenoid is a common failure point which will give the symptoms you describe.

pectelboy

Does effect the clocks on the dash ? If it does it's the map sensor , my mates Rs focus just had this fixed , they get condensation inside and fuk up , hope it helps

bailey1

iTrader: (2)

doesn't affect the car in any other way other than when your coming on boost and while boosting it can just judder/hold back/ intermittently sometimes it will pull through it sometimes it will get worse and feel more like a misfire.its had a new map sensor plugs coilpack air flow sensor boos hoses and it has no fault codes stored in pcm and on live data doesn't show enough data to highlight an area where I can go to so I'm thinking its got to be a mechanical fault like actuator / turbo.i had a st in yesterday and it drove so cleanly throughout rev range on boost so something not right!!!!

Jamie011190

Hi did you ever find problem to this? Mine does the exact same thing and I've ruled it down to the boost solenoid... I can find 3 different heavy duty boost solenoids but I'm wondering which is best, Collins do an heavy duty one, elevate do one and so do puma speed but does anyone know which is the best one?

Iain Baird

hi ppl did any one even find the cause of this problem am going out my mind hear mine has exact same Symptoms. Was it the boost solenoids ?

Jamie011190

i ended up doing a compression test and cylinder 4 and 5 was low compared to the others so that was my problem. Forged engine sorted it

anders rye

Did anyone solve this problem? I have the same problem. 2010 mk 2 rs bone stock 45000km. I don’t think it’s loss off compression. Boost solenoid changed didn’t work. No fault codes.

marcel2810rs

I’ve got the same I’ve had an engine check and found no faults changed fuel pump , maf sensor ,plugs,injectors and can’t find anything nor can a garage my next try is a fuel rail sensor or map sensor