[MooLard]

Hi there
My car has developed it next fault in no less than 3 weeks after a decent garage repair bill! The car does not seem to be doing any boost from the small turbo, if I put the gearbox in manual and drive hard at higher revs the boost eventually kicks in above 3k rpm. I guess this indicates that there is not a boost leak otherwise it would not boost at higher rpm.
Has anyone seen this fault code before: 03F01? It is for boost pressure sensor signal. I am trying to loan a vacuum gauge / pump tester to check the rest of the vacuum system, as this is cheaper than replacing sensors, does anyone have any experience with this problem?
I can see the largest actuator move when I start the engine, which indicates that there might not be a vacuum leak as the small / big turbo flap was able to direct exhaust gas towards the small turbo. I think this narrows it down to either the boost sensor on top at the back of the inlet manifold, or the pressure converter that does the wastegate for the small turbo.
Any help would be well appreciated.

[Chief Orman]

simplest thing is to make sure that the Boost hose from the intercooler did not come loose... it could be something more involved but that is certainly the cheapest thing to look at first... vacuum hoses and actuators are next

[MooLard]

Hi thanks for the reply I do appreciate it, this weekend I borrowed a vacuum gauge / pump tester and found that there does not appear to be any leaks in the vacuum system, which is good. When starting the car I can see the largest actuator move, I can't see the others at the moment. I took off the pipes off of the two visible actuators and tested that they both hold vacuum.
In other news I did some simple data logging and noticed that even when I drove the car hard at higher revs, I could see my water meth system turn on, so that was sensing boost, but the data logging of the MAP sensor was still showing no change. Is this an ok confirmation that the MAP sensor is faulty? And would this fault stop the small turbo from boosting in order to keep it safe?
Listening to the car it does seem like the small turbo is spooling up to a degree, I wonder if the flap that allows air from the small turbo in to the inlet is not working or being held in the wrong position. I can't tell which one of the two might be at fault, so frustratingly I am going to take it back to the local indy who did work on it a month ago. In the last visit my valve cover gasket had failed, it made a right mess so potentially this has ruiined a pressure converter, or electronic valve, or the MAP. Isolating which one is there I am stuck.

[rkstar9]

Originally Posted by MooLard

if I put the gearbox in manual and drive hard at higher revs the boost eventually kicks in above 3k rpm. I guess this indicates that there is not a boost leak otherwise it would not boost at higher rpm.

when my car has a boost leak at the intake it shows no power under 3k rpm then when there is enough airflow it will have power at higher rpms.

so you could still have a boost leak that becomes negligible once you have enough air flow.

one way to test it is to pressurize the boost tract from turbo to intake to make sure there are no leaks.

Originally Posted by MooLard

potentially this has ruiined a pressure converter, or electronic valve, or the MAP. Isolating which one is there I am stuck.

to trouble shoot the pressure converters without buying an extra part. swap the front pressure converter to the back and the back one to the front.

[MooLard]

Brilliant thanks for your feedback on this I really appreciate it. Due to lack of time now that the weekend is over it's now booked in to an indy garage on Wednesday. I will make sure to update you on the outcome.

[MooLard]

I have just got my car back from the garage and all is working once again. They replaced a pressure converter that controls the small turbo (can't tell which one visually at this moment in time), which improved things greatly. The fault code was still returning so they then proceeded to replace the MAP sensor and now all is fixed.

[rkstar9]

Nice this is good feedback!

hardly seen any turbo failures on this forum.