Spooks

Looking for a bit of advice as to what could be the cause of my overboost. Never had any problems with this before and nothing has been changed, no fuel added nor taken away,no additives etc etc.
Driving home this eve on motorway, accelerated in 5th to overtake and noticed my boost fluctuate from 1.1 bar to below 1 then sudenly spike to 1.5 and had fuel cut.Car had been perfect till then in fact was pulling like a train Sunday.
Thought this may be just a one off but my boost was all over the place on the way home from then. Spiking above 1.3-1.4 a fair bit.
Some datails about the car, fully decated MY01 UK WRX with STi panel filter, no other engine mods, all readings taken with my Defi guages.
Any opinions would be helpful.
Spooks

Neilo

id suggest getting a dawes or an electronic boost controller of some sort, ive heard that they can elliminate spiking.

RRH

check the hoses between wastegate actuator and turbo nipple, including any t-pieces to the boost gauge.

also clean out the boost control solenoid, and check the restrictor in the above mentioned tubes from turbo to wastegate.

1.5 bar spikes you can really do without. I'm guessing you got a CEL also?

Sounds like you have a leak somewhere. Fitting a boost controller would cure the sysmptoms, but, in the interest of longevity, i'd be more interested in preventing it happening again as it isn't doing the engine any good whatsoever.

hope this helps,
simon

Spooks

Thanks for the replies, yeh Im thinkin along the lines of air leak myself but Im dammed if I can find it....
Seems to be behaving its self today but wasnt pushing it too hard as I didnt want it to go bang.looks like I will have to get the remap sooner than I thought
Spooks

The_Judge

Could be a couple of things...

Sticking wastegate solenoid would be the most likely culprit for causing fluctuating boost levels. Was it recently serviced? What level's your engine oil at?

A split somewhere in the hoses between compressor outlet/T-piece/wastegate solenoid/wastegate actuator (effectively acting as a bleed valve) could cause an excessive boost spike...