Had this since i got the car but been my first scoob didnt realise it was a problem - just thought it was the turbo.

Whats happening is (and its not the clutch on take off - well as far as im aware!) say if im going up a steady incline holding the throttle in the same place the engine seems to have a cycle of speed up ease off, speed up ease off - without me doing anything. In addition to this, when i give it a bit of hockey or even sometimes on a simple acceleration there is a judder in the pickup - like the turbo doesnt know whether to spin up or not. Its not major league but noticeable but enuff to hack me off now after 6 months of it. I want a smooth pickup with no lumps in it! Not too much to ask i dont think.

Im thinking of getting it on the rolling road to see if they can locate the problem. Do you think they would be able to spot why? Never had a car on a RR before.

Im getting between 21/24 mpg (average i think) so i dont think anything is majorly wrong - but again im no expert.

Ive got a full decat SS magnex system and when i asked the guy that i bought the car off he blamed this??? Oh and a K&N induction kit.

Anyway - any help or advice appreciated!!

Look forward to your replies.

Cheers.
omen

 

Have you got a boost gauge? Sounds like a boost control issue.

I'd make sure the rolling road place is familiar with Impreza's - will save lots of time (& money!).

Richard

 

Sounds like you could have an overboost problem but we need to confirm a few things first....

When do you get this juddering boost, ie what gears and what sort of situations?

Do you get it in both hot and cold weather?

Try taking your car to the motorway, start from 70mph in 5th and floor it, if you get this juddering still then its overboosting.

Tony

PS, its quite easy to fix

 

I've got the same problem on my MY99!

it's been bugging me for ages. I didn't know if was electrical, clutch, turbo etc.

if it is a case of overboost, what is the fix?

 

I don't think it's overboost - I think it's simply the turbo spinning up causing pressure changes & turbulence in the inlet pipe/filter area, especially across the MAF. This then causes strange MAF readings & the so fueling is all odd as well, leading to turbo spinning up/down, etc.
Seems to be solved by extending the air inlet. As in a cold-air feed or similar (induction kit doesn't necessarily work as there is no further air-smoothing).
May be way off - but it worked for me

 

Cheers guys!

Well i did as you said and took the car out for some testing this lunch and after focussing on exactly what it was doing i have come up with the following findings:

If the car is going at speed with the engine at over say 3500rpm in ANY gear and i floor it everything goes great and the car picks up nice and smoothly.

From a standing start if i give it some welly up through the gears it seems ok. (so i reckon the turbo must not spin fully down - youl see why i say this)

The problem happens when i am running at around 2000rpm or slower and i put my foot down to pick up speed. (it is worst in 3rd - but happens in 2nd also). The car responds and starts to pick up speed and revs then around the 2500 - 2700 range through to 3000rpm i get 2, 3 or 4 shudders/flat spots as the engine/turbo picks up speed. As soon as i get through the 3200rpm or so it is ok again.

It may not sound much but its really doing my head in and is very noticeable! :-(

So over to those in the know again. Have i given you enough info?

TIA

omen

 

Oh and i dont have a boost gauge - sorry! :-(

 

Plugs could be on there way out?


[Edited by mega_stream - 8/14/2002 2:45:52 PM]

 

Ah - spool up. Nothing weird & wonderful
The standard fueling is a little iffy on some models and the induction kit is unlikely to help.
Just blast through it if I were you

[Edited by nom - 8/14/2002 1:27:50 PM]

 

Have been doing so for 6 months and had enuff of it really! Beginning to wonder if ive got a fat hamster turning the turbo! ;-)

 

The problem was also present pre-induction kit as well.

 

I've just had my 30k service, so my plugs are new (So they tell me anyway)