Focus st boost problem
 

Can anyone help? I got in my car the other day and im only getting a quarter boost. I looked on dreamscience's website and it seems map sensors go down and cause the same problems little or no boost at all. But could it be the boost pressure solenoid?

I would say the boost solenoid, personally.

Martin

That was my first though but after reading there website made me wonder if its right.

Anyone had this problem?

Mine was only getting 1/4 boost, I put a new map sensor on it and also a new oil breather hose that had split and it was all good again.

Check this hose, it's the one that goes from the middle of the cam cover through the inlet manifold and connects to the oil filter housing. If its an early one then the hose is quite plasticky and splits around the corrugated bit. The newer hoses are rubber and much better.

Yer i changed that a while back when the oil filter housing needed replacing. So I should go for the map sensor then? did yours throw any fault codes up on the fault code reader?

Yes it did throw a code, afraid I can't remember what it was now though. It was due to the split hose but I had already ordered a map sensor so got a hose as well and put them both on at the same time.

It could either be that or the boost solenoid although I think that if the boost solenoid had failed it would either make zero boost or overboost and be hesitant on full boost.

If it were me i'd stick a map sensor on it as they are the easiest to do, boost solenoid is a nightmare!

Thanks I will get one ordered tomorrow and see if that solves it.

I would of gone boost solinoide first myself

I did go boost solenoid in the end as my mate had a spare one which he knew was good so I put that on today and its back to full boost.:DD:

Great stuff you got to love a bit of boost

glad it's sorted mate did you have much trouble changing it? I think it's a job that's easy when you know how!

It was ok as I had use of the ramp in work but those 3 prong spring clips which go on the tubes are a bit fiddly I did it in my dinner hour .