LEECOS

I HAVE BOUGHT A 1997 UK 5 DOOR FOR MY WIFE AND ALL WAS FINE , GOT AN EXHAUST FITTED STILL FINE BUT AFTER A WEEK OR SO THE CAR SEEMS TO BOOST THEN HIT A BRICK WALL , IF SHE DRIVES IT STEADY IT IS FINE BUT GIVE IT A HEAVY FOOR AND IT HITS THE WALL,
WHAT COULD IT BE ???????

1997 FACE LIFT
WRAP AROUND SEATS
THE CAR HAS DONE 111000 MIL FUL HISTORY
ONE OWNER
MONGOOS EXHAUST
BAILY DUMP VALVE
APART FROM THAT IT IS BLISS TO DRIVE

Troubled1

Hit the Caps Lock,

Sounds like overboost causing fuel cut, To see whats happening you could do with a boost gauge, Then if that is the problem ( good chance it is) A good cheeap cure would be a Dawes Boost controller etc

LEECOS

What would cause this exhaust ?? ( it is a de cat type ??? )

smiff99

I had the same problem with my 98 wagon shortly after I bought it, it turned out to be the fact that oil had been overfiled by some muppet in the workshop. If you check the dip stick you will notice that there are 3 marks, two holes and a notch. Starting from the bottom up, Low, Full and finaly the notch for when the engines hot to allow for expansion of the oil, this is the one they filled it up to, but, with the engine cold !
The result was that the oil contaminated the boost solenoid thus intantly cutting power when under boost, like hitting a brick wall.
If this is the problem, then the cure is to obviously drain some oil off to the correct level and then clean out the solenoid, you can do this apparentley with brake cleaner.If you search around the forum you'll find the correct way of doing this, however in my case It needed a new one,about £150 If I remember correctly.
Hope this helps.

LEECOS

[NO THIS CANNOT BE THE PROBLEM AS OIL CHANGED AND SERVISED AND STILL DOING IT I HAVE HEARD OF THE MAF NEEDIN CLEANING ???

Keigo

From what you are describing, it is very likely to be a fuel cut, as previously said.

Is the Mongoose a full decat, or front cat back? It is more prone to overboost with full decat. Dump valve will also add to the overboosting factor. First, ditch the dump valve. It's just for noise. Does more harm than good to performance and/or car, IMHO. You will also want a boost controller and boost gauge, set the boost level to about 1.1 bar. Fuel cut on MY97 IIRC is 1.15 bar or thereabouts, so 0.5 bar off limit should give you a max performance without the need for a fuel cut defencer or a ECU remap to raise the fuel cut level.

A contaminated MAF could be the problem as well, as you say. But on MY97, MAF isn't as fragile as MY99-00 models, though

Hope that helps.

LEECOS

Is the boost set by the actuator as with cosworths if so not a problem,
the exhaust is a full system turbo back ( no cat ) where is the maf sensor ?
The dump valve how does this affect the performance of the power as it only relecess excess boost from the intake ???

also why did this happen a week or two after the exhaust was fitted and 200 mil ???

Lee Pearson

Jay m A

iTrader: (2)

Does it stop happening with a full tank of fuel?

Does it happen when booting it off a roundabout?

Does it not happen when on the motorway?

If the answer is yes then it could be fuel surge - my wagon has experienced this with half a tank of fuel in.

LEECOS

WELL THE FIRST TIME IT HAPPEND I ONLY HAD A SMALL AMMOUNT OF FUEL IN AND WAS COMMING OF A ROUNDABOUT SO I THOUGHT IT WAS THAT SO I FILLED IT UP AND IT DIDNOT DO IT FOR A FEW DAYS THEN ON THE WAY BACK FROM A TRACK DAY AT CROFT ( NOT IN THE SUBARU ) IT STARTED ALL THE WAY THERE IT WAS FINE ????

JohnRoly

Had this problem on my 95 Wagon, gradually got worse and worse. Wasn't the boost solenoid (replaced), wasn't the MAF/Oxygen sensors (replaced) wasn't the restrictor valve (replaced). Turned out to be a leaking actuator! If you can suck and blow down the actuator pipe, then you have a leak, and hence the boost creeping up over allowed amounts, and fuel cut is initiated. Worth checking before going to a lot of expense (just ask my warranty company ;-))

LEECOS

CHEERS FOR ALL THE HELP , WILL TRY ALL OF THESE TONIGHT AND LET YOU KNOW

Turbo_Steve

If it happens in every gear (which is sounds like) in every weather, it's the following:
You've just had the exhaust fitted and the plumbing from the turbo to the solenoid has probably been disturbed. Check the hose going between the nipple on the turbo and the actuator is intact, and then check the hose to the solenoid (on the drivers side suspension turret). I can almost gurantee that one of these hoses has been injured or not put back on properly, or the T-piece has become brittle from heat and snapped during the disturbance or similar.

Bet you a pound

If it happens intermittently, you either need your boost solenoid cleaning, or your exhaust is messing up your boost control. If it is the exhaust, you can either get a Dawes device and boost gauge fitted, or you could take it to a subaru shop and pay about £5 for a smaller restrictor to be fitted, smoothing the boost control.


AND TURN OFF CAPS LOCK IT'S RUDE LEAVING IT ON PEOPLE THINK YOU ARE SHOUTING.

LEECOS

Cheers, sorry for caps lock but it is so much easier to type with it on and faster.

Lee

Turbo_Steve

Np. It's just polite

Gear Head

iTrader: (2)

I also get a 'hitting a brick wall' sensation if I have less than 1/4 tank of fuel. Put it down to fuel starvation, never happens at any other time

911

I have an Sti v3, and can tell you that fuel starvation is very mild compared to the fuel-cut 'brick wall'.
The exact same happened to my car when it had the stock exhaust on it. Went to Power Engineering in the end to sort it with a Blitz Boost controller. Perfect since.
The car has had a full decat Magnex 3'' system since, and all is well now for 3 years.

Well worth trying all the above suggestions, I did , but in the end the Blitz sorted it all.

Now running 1.3 bar = 314 bhp = bliss............

911

LEECOS

Had a go at most of the above and still doing it went to mr wallis house not much out of place that he could see , do you think it could be the ecu that needs a fault code removing the light is not on but there could still be a fault after the exhaust was fitted ???????

Andrew Timmins

I had the same problem on the MY95 I owned. It turned out to be coil packs. Off boost the spark was strong enough to ignite the fuel, once there was boost the spark was too weak for ignition. If I drove gently the problem was not evident at all.

Jay m A

iTrader: (2)

Fuel filter? fuel pump?

Have you checked these?

LEECOS

New fuel filter fitted pump ok could be coil pack as if driven gentley through 3500 sometimes will rev through.

Can the ecu be tested even if the fault light is not on just incase the lamp has gone or the wire has been cut ???????

brunny42

the light should come on with the ignition turned on, this tests the wiring and bulb. after a few seconds it should go out.

LEECOS

Can anyone tell me or show me where the light is on the dash . The dash is a anolog type 1997 .

Cheere
Lee