Swift Cee

Hello people, I'm lacking boost on my 93wrx. Ive checked the error codes (ALL OK) but after that im not quite sure where to look next. Basically its not far off driving in limp mode. It just seems to be holding back once i get into the higher revs. and its starting to do my nut in.

Ive just sorted out the knock sensor in the hope of getting me out of limp mode! I Cant win!!!!

What can i do? Im thinking new set sparks? dont say coil pack!!!!!! Christmas is coming!!

Any help is much appriciated chaps.

Please help!

jaytc2003

iTrader: (1)

its probably is down to either your sparks or coil packs
Your not having much luck with this car are you?
Do you know when the plugs were last changed? If not it wouldnt do any harm to change them

RICH WILD

What is it boosting to?

vessy

When you get yours fixed can you come and do mine!!!

It seems to be happening to a few people at the moment, maybe something to do with the cold air, mine is a nightmare in 1st, boost comes up then falls back down, and can feel boost hunting through all gears.

Check the pipework behind the air intake box, mounted to the r/h strut. Make sure all the pipes are on securely and no splits. Have you changed oil recently? if so it may be a good idea to clean through the boost control solenoid and restrictor. A simple search on here will give you all the info to carry this out.

I've checked all this on mine and still have the problem so if i find my cause i'll let you know

Jolly Green Monster

iTrader: (4)

pipe leak / split..

boost control solenoid dirty and needs a clean out with brake cleaner...

Wastegate actuator faulty..

Wastegate actuator arm disconnected..

Simon

Swift Cee

Tell me about it, getting a bit p*ssed off with it now. Just spent a ton on it and this is how she repays me!!!! Arrggggh!!!

Ive got a brand new set of platinum babies to go in but its a case of being in the right mood for it!. Id say they could do with a change. the coil packs 'look' ok. Im in the process of resetting the ECU. Fingers crossed!!!

cheers jay

Swift Cee

any visual aids on how-to-do this simon? I know where the boost soleniod is. Is it a case of whipping it out and giving it a good ole clean?

thanks

swift

Swift Cee

No boost gauge Rich!

cheers

buzzard

remove short from knock sensor!

andy10

[QUOTE=Swift Cee]Hello people, I'm lacking boost on my 93wrx. Ive checked the error codes (ALL OK) but after that im not quite sure where to look next. Basically its not far off driving in limp mode. It just seems to be holding back once i get into the higher revs. and its starting to do my nut in.

I've been having similar problems tonight. Boost guage is at -1.7 normal driving approx 2000rpm. 0 at 3000rpm and maximum of 0.5. Couldn't get passed 4000 revs without the car shuddering violently. Max speed was 70 although i kept it down to 40mph so that I could get home without (hopefully) doing any more damage.

Dump valve did seem to be hissing slightly. Could it be as simple as a split hose?
Anything else I'll be paying for.

tath

it sounds exactly like a split or loose hose. My tmic had wiggled free of its moorings a while ago and when i put my foot down the hose would pull off the throttle body resulting in the same symptoms. The problem was that every time i pulled over to check, it popped back on! Bit of a head scratcher...

Journeyman

I have a similar boost problem. I've spent a few weeks trying to get to the bottom of it. The car's a UK MY99. It usually boosts to +.98 bar and pulled really well holding the boost smoothly. Just recently the car would hesitate above +.7 bar but continue the boost upto +.98bar according to the boost gauge and would pull all be it in bursts. MAF and Lambda are both new and functioning correctly and there are no fault codes on the ECU.

I then followed advice and removed the boost solenoid (standard 2 port) and cleaned it with brake cleaner. I've replaced all the boost pipes from the solenoid with new genuine subaru parts. There are no air leaks.

Now the car will not boost beyond +.7 bar

Please can anyone suggest what steps I should now take to get the boost to it's original +.98 bar?

Journeyman

bump. Please can anyone advise?

Isoproturon

Just out of interest, what fuel are you using ?

Journeyman

I usually put Optimax in it however the last tank was low sulphar stuff.
I've filled up again yesterday with optimax.

I have run it before on low sulphar (uk car so should be fine) with no low boost issues.

Journeyman

Ok I've fixed the low boost problem. There was a restrictor in the original pipework so I put the old pipe section back on and it now boosts to +1.0 bar
Problem is my hestitation is back again

When the car hesitates I do not see a drop in the boost pressure on the gauge. Would this mean that the boost solenoid is working correctly and that the problem is elsewhere and if so where should I look next?

stubbz

Sorry i have no answers only Questions ! (Sept99 UK)
I too have a boosting problem, The garage said proberly the turbo is creamed and needs replacing, i don't belive them.
The turbo starts boosting and then loose boost up the rev range, i have taken off the actuator and my garage have tested this and seem ok, how ever they could not tell me what the crack presure was.
So i put a camera under the bonet and drop up the road and its definatly the actuator pulsing in and out. Movie file here. http://www.stubbz.eclipse.co.uk/actuatorsmall.zip
Graham Goode reconmended i clean pipes and boost presure valve (solenoid).
> Journeyman. i seem to have the same problem, i knew about the restictor and if i remove it the fluctuating problem disapears basicly as you have now guessed the boost is lower. I wanted to get a boost guage on the pipe work but it apears you have done that already. I will clean pipes and boost valve but now i am not hopefull, has anybody tried replacing the Actuator ?
Is it ok to use brake cleaner to clean the pipes or am i better of getting some induction cleaner fluid ?

stubbz

Also 4got 2 say this started to happen just 2 weeks after a remap with slightly higher boost.
surly it has to the the actuator. ?!?

Just found this whilst searching. Worth a look !
http://bbs.scoobynet.co.uk/showpost....84&postcount=7

Stubbz

buzzard

there are many many causes of this prob.

journeyman ; may be worth doing an ecu reset since you have used low grade fuel recently, cleaned solenoid and replaced pipes that may/may not be exactly same internal diameters as originals and ecu needs to relearn behaviour of current setup.keep restrictor in actuator pipe.

common causes include;
poor quality fuel
boost solenoid
leak in intake system including manifold gaskets
leaking exhaust gasket or blow in exhaust manifold
up-pipe(very common)
actuator
coolant sensor
boost pressure sensor
plugs/plug gaps
coil/coilpacks
collapsing or partially clogged catalytic converter
baffles in back box moving under boost and restricting exhaust flow
turbo

there are other causes but it is usually one or a combination of the above. when you know what to look for the above list doesnt take as long to do as it looks.

hope thats of some help.
good luck.


just remembered a prob i came across twice;

the nearside intake cam had slipped a tooth on the timing belt.
i put it down to the battery smacking the cambelt cover when driving on fast bumpy roads and upsetting the timing. the battery hadnt been bolted down in each case and hasnt happened since. worth checking.

Journeyman

stubbz.
Yes I used brake cleaner to clean the solenoid although I disconnected it before I sprayed into it so I'm not sure if it did the job as the mechanism was not clicking over. A fellow scoobynetter is sending me a different solenoid and if the electrics on it fit I'll try it and see if it makes any difference.

Could you explain the actuator effect you see in your video (wild vid btw!)
and what the consiquences might be.

My boost pressure (according to my gauge) does not fall whilst the car is hesitating. The gauge pipe I've fitted comes directly off the top of the air inlet manifold. The car hesitates only whilst the boost is increasing between +.7bar and +1.0bar. As soon as the boost drops back to below +.7 it's a smooth ride again. Are we describing the same problems as you say your boost drops?. just a thought.

I've replaced the intercooler -> throttle body with a brand new samco so i doubt it's that. The MAF is new as is the lambda.

buzzard.
Thanks for the list it's just what I'm looking for right now in terms of fault finding. The garage recently replaced a manifold gasket I wonder whether that maybe faulty. I have a decat centre and it does not have the original gaskets on it (jap import) so I believe the garage used some sort of sealent to get it coupled. Could it be that?

I'll do an ECU reset as you suggest.


When I took it to the Subaru garage with this problem they just put another restrictor in the pipework, the pipe from the intake to the solenoid. All that did was lower the boost so it would not boost above +.7 bar. Of course I was not happy with their 'fix' so I removed it. They were very good about it and refunded me the hours labour charge for taking it out, diagnosing it and adding that mod. Thats when I replaced all the solenoid pipework and cleaned the soley itself.

The garge have asked if I would like to take it out with one of their mechanics. I may well take them up on that now I'm a little better informed.

Keep you posted.

Jolly Green Monster

iTrader: (4)

sound like misfire due to plug gaps too large or coil problems..

Journeyman

Presumbly if the plugs are old and worn the gaps will increase? (sorry newbie question)

Do you know where I can find the coil pack on a UK MY99?

stubbz

Journeyman, thanks for the info on the brake cleaner, i will get cleaning over the next few evenings.

afaik
The " Actuator Effect" as you described it is as far as i can tell whats causing the problem. The actuator is only ment to work when the boost hits a preset level (controled by the ecu and the crack level (operating pressure) of the actuator)).

The actuator arm directly connects to the waste gate on the exhaust side of the turbo, so when boost rises too high the waste gate is opened and the gasses are spilt down the exhaust pipe instead of turnung the turbo vane / fan, this will of course reduce the air intake volume of the turbo.
Its does sound like the same problem, (although i do not hav a boost guage fitted) as when i remove the restrictor from the boost pipe i have reduced boost and hence no hesitation problems.

let me / us know if the boost valve replacement works

Anybody got a working actuator off a V reg Impreza turbo they can spare for a while ?

Stubbz

Journeyman

ok got that thanks. Certainly could be same problem then.
My boost gauge hose connects directly from the top of the air inlet manifold so if the boost was dropping above .7 bar pressures (after boost solenoid) I presume it would not show up on my boost gauge as dropping at all. I think I'm right in saying that? hmm.

btw did you say you'd changed the plugs and checked coil packs already?

stubbz

no,
plugs and coil pack would not cause the actuator to fluctuate.

Stubbz

Jolly Green Monster

iTrader: (4)

no but the subsequant misfire would.. misfire loss of boost, actuator fluctuates.. etc..

Journeyman

Driving home last night I opened her up very slowly on a long straight road increasing the throttle very gradually and managed to reach +.9 bar without the car hestitating. This might appear to indicate that the hestiation is brought on under heavy load in which case would that narrow it down in terms of finding the faulty component?. Does anyone have any suggestions?

Jolly Green Monster

iTrader: (4)

plugs, plug gaps, ht leads.

Swift Cee

Put a new set of sparks in there last nite (Dam it was cold!!!!!) and reset the ECU. Got it going today and started off ok, took it easy foir a bit and then booted it for a bit, seemed to be boosting ok (id say normal) then after a while it seems to have slipped back into this lack of boost mode!

Arrrggggghhhh!!!!!!!!!!!!!!!!! anyway its a bit better than it was (probably down to the new sparks) but its nowhere near what it was. I checked the pipework which looks ok cant see any rips or tears.

SQUARE ONE!!! Think ill try the boost soley next, anyone know how much a new one is?

Ah well there you go.

Cheers lads

Swift

Journeyman

'bout £170 I believe