WReX1990

Hi guys(& gals),
I need your expertise and guidance please,

I have a 95 WRX (import) saloon, pretty standard with about 40K on the clock.
The Engine and running gear are in top condition. Also holds a steady boost of 0.7 / 0.8 bar in all gears. (proper HKS boost gauge)
Just fitted a full 3" exhaust system from Turbo back, 'so no cats' , and inclusive of an up-pipe!
Quite a loud set up so has a removable Bung in the tail.
Fired up and ran ok...

Then done a full service, all filters, oil etc... to make certain the car is fresh.

Was all fine for a day or 2 with same steady boost.... I thought the boost would of naturally increased now with the lack of restriction(one reason for the full exhaust system), but no it was more or less the same as before.

I have been running it with the Bung in so far (2 days since the changes).
Removed the bung yesterday and after a couple miles the car started to 'over boost' like crazy! (coincindence????)
1st gear 1.0 bar, 2nd gear and above goes past 1.5 with the fuel/boost cut kicking in naturally.

It's not spiking, it's just a steady mad boost run away!

I initally thought it was the sudden free flow without the bung, so re fitted the bung and no different, same mega over boost.
Plulled the MAF and Boost sensor to check all connections in and around that area with all vac lines etc, and yes all seems fine there.

So here lies my problem.... Car runs great, but plant it and Major Over Boost....

Any takers with some advise, suggestions, info or even links to shed some light on what may be wrong?

All help appreciated.

Rgds
D

myblackwrx

iTrader: (1)

well it shouldn't go to 1.5 bar as fuel cut is just above 1bar.

it shouldn't boost more because of the exhaust just spool up earlier.
Is the restrictor pill in the bottom hose off the boost solenoid
https://www.scoobynet.com/general-te...re-should.html

WReX1990

Hi, yes it does indeed 'fuel cut' as it should at around 1.2 bar, but it takes the ECU a second or 2 to react and engage this, but the boost is soooo rapid that when I stick it to the floor she runs well into 1.5 nice and quick and then the 'fuel cut' jumps in to calm it down at about those levels...

With regard to the spool, yes it would spool more freely/quickly, but at the same time this free spool may allow an 'over boost' situation or at least a creep.... it is now a huge decrease in restriction now..
The funny thing is she went from a steady 0.8 one day to double that the next!

And Yes I checked the 'pill' and it's nicely wedge in where it should be, it also seems unobstructed.

Saw a thread mentioning 'excess oil level' may cause the soleniod to get contaminated or such... I had a look at the solenoid and no evidence of Oil there really, or am I looking at the wrong thing/place?
Also if someone can shed some light on this 'excess oil' issue, please feel free to explain to me as I can't see how

Thanks and keep the suggestions coming...

Rgds

T1000

To control the boost levels and prevent it from overboosting you could get an electronic boost controller. E.g. Apexi AVCR or Greddy Profec B spec II.

WReX1990

Thanks, I am indeed considering throwing on a Profec B... but I am was just trying to understand why one day she was fine with perfect steady low boost level then the next day 'bang' double shot....

I'm just about to go outside and have a play with it all again in case I missed something.
I'll report more as I go along... but please do keep the suggestions coming.

Rgds

WRX Blues

This is spot on advice. My Sti III suffered in exactly the same way and ruined my experience until I fitted a Blitz DSBC set to peak at 1.25 bar. From then onwards it was fine and made steady and accurate boost evrytime in all conditions
I am not sure why it happens - someone will probably come on and tell you, but I can say that I had the car looked at by several 'expert' garages who never actually managed to diagnose the problem and tried all sorts of cures.
The Blitz was fitted by Extreme Scoobies and I asked them to hide it behind the drivers footwell so I would be tempted to keep cranking up the boost
I was initially tricky to set up and meant lyinf painfully unter the steering column but was well worth the effort.
I should add that I had the car rolling road tested for fuelling (ran it on Optimax and Millers back then) and also fitted and knocklink just to be safe (and because a scooby owner and their money are easily parted)

Fizz

iTrader: (1)

could it be coincidence that you have just done a service? could it be a fouled up line somewhere to the actuator or the wastegate?

WReX1990

Guys thanks for all the inputs,,,,,,

Stripped the intake side and Vac lines and started again from the begining.
I found the problem
To cut a long story short, the Vac line from the Turbo out to Solenoid came loose. Came loose as it had a split.. Didn't see it first time as it was rather hidden from plain view and needed to remove the Intake pipes to get at it.
Very very simple problem that had me scratching my head for a bit as I knew it had to be a fairly simple issue, because as I said she went from steady 1 day to super crazy the next....

So smiles again as she is brill once more...

Oh, while playing with pipes and vac line(BTW I replaced them all with proper silicon), an old manual controller was among my old box of tricks so I quickly stuck it on, only takes 5 mins and a few runs to get right...
Now set to 1 bar, she is rock steady throught all gears and WoW, what a difference with the full exhaust and boost increase..luv it...x
Don't worry I also have a Profec B spec II sitting there which I will get around to doing when I have more time...

T1000

Glad you got it sorted in the end

chris-RB5

Where did you get your silicon hoses from having the same problem