BOOST PROBLEM
 

my sti7 is suffering from an annoying boost problem, on half throttle the boost gauge constantly goes up and down between 1.0 bar and 0.6/0.7 bar, about every second it will drop and then return to 1.0 bar, but on full throttle it's okay at a steady 1.0/1.1 bar.
i have checked the intercooler hoses for splits and loose clips, but have come up with nothing, any ideas?????

You need to add a bit of detail....

1. Mechanical or electronic gauge ?
2. Where is it plumbed in ?
3. Has it always done it ?
4. Is it just fitted ?

DunxC

P.S. As a registered smart-arse I'd say you've plumbed it in to the wastegate solenoid feed, and it's showing you that working.... mine's plumbed in to the fuel pressure regulator take-off on the front left leg of the inlet manifold.

HI, its an electrical gauge, i only recently got the car, it's an import and i'm the first owner in uk, so don't know its history. the gauge is a sti genome with a control box. i did have the gauge of for the sva test, there are 2 holes in the gauge to plug the connection into, could putting the connector in the wrong hole cause this fault maybe?????

i swapped the connector on the boost gauge today and it made no difference :( this is an annoying fault!!
would the problem have anything to do with the bailey boost gauge??

If its just the gauge at fault and not the performance of the car i would think it was the gauge feed. The feed from the manifold pulses rather than a constant pressure. If the bore of the feed tube to the gauge is too big it will pick up on these pulses.. You can fit a small restrictor it the pipe to smooth the pulses out. I used part of a biro pen nib!

Am i right in thinking you have a feed coming off the manifold into a control box then onto wires that go to your gauge??

If so i would make the bore of the tube going to the box smaller..

Can you feel the boost surging up an down or is it just what you seeing on the gauge??
If its car related rather than gauge plumbing, its probably a pressure leak between turbo and throttle body somewhere or a sticky b/s.

yeah, i can feel the car surging as the power increases and decreases, its very noticable, losing a lot of power!!!

Sounds like the gauge is showing you what the car is actually doing, mine does this at 1.5 bar, but I assumed that was because the turbo is close to it's limits at this.

You may need a specialist to tell you what's wrong, or just clean out all the boost control pipes to remove any oily deposits, just in case they are blocked.

HTH

DunxC

yeah, a mate suggested doing that also, he also mentioned cleaning a boost solinoid??

N602 WRX mentioned a sticky b/s, whats the b/s ??

boost solenoid !

HTH

DunxC

off course it is, stupid me, cheers, will try spraying it with carb cleaner today. fingers crossed :thumb:

great news guys, i fired some carb cleaner in the boost solenoid and it's sorted, :thumb: thanks to N620 WRX and dunx, nice one lads :notworthy