GreedoGC8

Another day, another problem. I recently built my gc8 a new engine and have been running it in, but i have an issue. My engine will stutter and judder as you put your foot down when theres some temp in the engine but its not at full running temp, and when it does even out at full running it doesnt want to know about boost at all, big faceplant the windscreen boost cuts.
My check engine light is on (code 45) telling my my pressure sensor has an issue, so ive replaced both sections of it and reset the ecu a few times, but the boost cut and the code 45 are still there. Ive replaced all the vaccum line, made sure the pill is still there allsorts, and i dont know what to do now. Anyone have any experience of this?

GreedoGC8

I took my scoob out for a drive after posting this, and annoyingly after a week of messing around trying to sort it myself as soon as i asked for help i find the cel has gone along with the boost cut, typical lol.
All is not well still though, as now when you put your foot down it doesnt seem to be able to choose between 6 and 14 (i think z4 are 14) psi, sort of stuttering erraticly between the two. I have a gfb ebc to fit but im too worried ill pop the new engine if i take the ecus ability to go into low boost, its too clever for its own good imo lol. Wtf is going on with it?

GreedoGC8

Bump, someone on here must have had this problem, hesitiation on boost and the occational misfire? Doesnt show a cel but shows 45 when tested

GreedoGC8

Cor, its a good job i use this site, or i wouldnt have access to this vast wealth of knowledge and experience that assists me so hugely whenever i have an issue with my scoob lol. Through process of ilimination i found that if i unplumb my boost pressure solinoid and just run straight from pressure source to wastegate it runs perfectly, although boring at 6psi. This leads me to think the solinoid is unable to level the pressure ojt at 12 or whatever and is spiking into boost cut territory. Ive tried the cleaning method with some egr valve cleaner but it made no difference. I also have a spare that does the same thing, can anyone shed some light on how to fix THIS problem please?

SAM-UK300

iTrader: (8)

Mate - Try googling Impreza Boost Spike, comes up with lots of threads.
Has the car been mapped at all?