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Boost Issues, '94 Wagon

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Hi All,

I'm Andrew from Newcastle. I have just introduced myself over in the newbies section.

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.


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 smile.gif

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

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Boost creep is sometimes caused by a faulty actuator not controlling the wastegate accurately .

Especially if it's decatted and not remapped as the ecu might struggle to keep the boost targets in the standard map parameters.

It could just be a leaky vacuum pipe or the boost solenoid might need to be cleaned or replaced

Have you done a classic self code check? (by connecting the plugs under the dash)

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I've been doing some reading, I would probably describe it as 'partial throttle, full boost', then when I go to full throttle the boost drops...


Would 'partial throttle, full boost' be caused by the same problem as boost creep?


No I havent done a the self code check.. been looking at how to go about it... I think I shall have to give it a go when I get a spare five mins.


Also I intend to clean the boost solenoid soon... Whats the best way of tackling that?

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I fear matt's method of cleaning may be a little extreme,

Plug in both sets of the diagnostic wires. Open bonnet remove hoses from top and bottom of boost solinoid spray brake cleaner into top hole and let it come out the bottom, keep spraying for ages and a rag is handy to catch all the **** that comes out the bottom.

Re assemble and start car,

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I shall have a look see that the heat shield isnt touching! I couldnt see anything last night when i.looked that would cause obstruction!

Thanks I will get some brake cleaner today and give it ago tonight! Do I start the car with the diagnostic wires plugged in?

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Don't bother to start it, once you've plugged them in just turn the key to the 2nd 'on' position you'll here the fans and relays cycle through the self test sequence.

I did mine not long back and the sound of the clicking it makes was a lot quieter after i'd cleaned it.

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Do you have a two or three port solinoid ? The pill on a two port lives inbetween the small turbo outlet Nipple and the tee piece.

By all accounts the restrictor on 3 port systems is located in the line coming out of the bottom of the solinoid,

Somone could have changed the pill to give more boost or it could be clogged up.

I'll pop a pic up shortly of location if you want ?

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I have the three port solenoid... So the restrictor should be in the bottom pipe to the solenoid? I have picked up some brake cleaner this morning so will set about cleaning the solenoid tonight...

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I 95% sure it hasnt been decatted, but it has had a k&n fitted...

I cleaned out the boost solenoid tonight and its made a huge difference, however there is still some hesitation/ fluttering... I think I will give it another clean out tommorow night after the commute.

And yeah i thought something didnt add up with your last post!

Thanks for all your help, its much appreciated!

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