swanie999

Hi All,

I'm Andrew from Newcastle.

Bought my first impreza, a '94 Import WRX Wagon a month ago.

The car is generally very tidy and has been looked after, with no major rust or any severe mechanical problems. The car isnt using any oil or coolant.

Anyway down to the boost problem. Here's a link to a video I recently uploaded to YouTube.

https://www.youtube.com/watch?v=nwCe...ature=youtu.be

The problem gets worse when the car is under heavy load and I have experienced fuel cut once or twice.

Also if I lightly feather the throttle, the boost stays high and the car is like a rocket, however if I am heavy footed the boost drops low and the car feels like a diesel truck!

I am completely new to subaru and turbo ownership, however I would say I was fairly competent at some home mechanic-ing (replaced engines etc).

If I could rattle the brains of you more experienced owners at diagnosing the problem, I may be able to have ago at fixing it myself!

Anyway thanks for any replies in advance!

Cheers swanie999

P.S Sorry about the shania twain and shaking in the video!

jameswrx

iTrader: (4)

What exhaust do you have? Obvious cause would be decat exhaust.

swanie999

Thanks for the reply.

95% sure the car is not de-cat.

Why would de-cat cause those problems?

jason_2013

Those early import wagons had the ecu's with probably the lowest boost target of any turbo petrol impreza. A standard WRX wagon is supposed to settle at about 7 psi with an initial peak of around 10 psi. That's how it is. It's actually a good thing because the engine is going to be in better condition.

You can improve the boost though.

Edit - well the boost seems normal looking at the video. When exactly are you getting 'fuel cut' ? Because that is obviously not normal. (could it be a misfire?, because cracked ignition coils are a very common failure on those early imprezas)

swanie999

Thanks for the reply Jason.

I have experienced what I assume to be fuel cut twice.

Once when the car was fully loaded, pulling out from a junction giving it the beans, through all gears the boost was engaging fully, completely cutting out and then coming back in.

Second time was just on the commute home from work again pulling out from a slip road giving it full whack in fourth the boost engaged, stopped completely and then engaged again!

After a conversation with Alyn at AS Performance, the coilpack theory was thought to be unlikely, as the symptoms I described didn't match broken down coil pack symptoms, however this was before I had fitted the bosst gauge.

Is there any reason why I can get the car to really go when I feather the throttle (probably on overboost)? A dodgy modification possibly, sticky actuator, boost control valve?

The car has had a K&N fitted and I presume some blow off/dump valve as when letting off throttle car makes the typical rude by noise, could this be affecting boost?

Please excuse my ignorance, but I am completely new to subarus!

Rick2014

iTrader: (3)

It does sound like fuel cut.Have you had a look to see if your actuator has been played with.Have you got any on board electronic boost controllers and what fuel are you using

swanie999

I am not aware that the actuator has been played with or the fitment of a boost control valve.

But im still learning where to find everything under the bonnet!

Where am I most likely to find an electronic boost controller?

Are they the only things to cause fuel cut?

kevo10

When it happened, did you have a low fuel level at the time? Seems odd that it happened pulling away at a junction and going round a bend

kevo10

Maybe worthwhile gaining access to the fuel tank (under the rear seats)and check the filter on the pickup in the tank

swanie999

Kevo10,

I never let the fuel level go below half so I doubt its because of fuel level, but thanks for the suggestion anyway!

What does effect it is the load on the car, ie the weight its pulling around!

Rick I only use super unleaded.

Could a dodgy boost control valve cause overboost?

kevo10

Changed the fuel filter ?

swanie999

It was changed around 3000 miles ago, the previous owner was a mechanic and completed a major service on it.

swanie999

I shall have a look at the pickup filter as well, see if that's in a bad state...

kevo10

Just a quick thought. W hen yu say loaded, do you mean towing ,or passengers? If passengers , take the seat out and check the electric cables and connections to the pump. These are known to overheat and melt causing fuel problems. Then if the passengers use the seat , it can cause a break in the circuit

swanie999

Not passengers but the rear seats loaded up with luggage! Looks like Im going to be taking the rear seats out!

So what is most likely to cause over boost? Fuelling or a dodgy boost control valve/ sticky actuator?

kevo10

Would start with the easiest and quickest. the fuel tank connections under the seat and go from there mate . At least then , you can rule that out