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Old 24 Apr 2011, 09:34 AM   #1 (permalink)
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keeps holding back

hey guys , im new here
i bought a r reg subaru yestaday and it runs fine and tickovers fine
but when my foot is down in 4th and 5th and sometimes 3rd it will jerk back really hard when you get to a higher speed
this was tested on a motorway that didnt have many people on at the time,
when i got the car we obviously didnt notice the problem untill we got on the motorway to give it a run back home,
the car has a decat
is there any tests i can do to narrow it down to what it can be?
really annoyed with it and i want to make sure it doesnt end up ruining the engine, only does it if floored in high gears

ive tried starting the car and unplugging the MAF while running and it starts to die and then cuts out, not straight away but after a couple of seconds

any ideas what i can try now

Last edited by ashbuster; 24 Apr 2011 at 09:42 AM.
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Old 24 Apr 2011, 09:48 AM   #2 (permalink)
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Re: keeps holding back

Welcome to .org mate,
What info do you have on the car, when was it last serviced ?
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Old 24 Apr 2011, 09:55 AM   #3 (permalink)
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Re: keeps holding back

i have no history with it mate, owner lost all paperwork,
looks like its fresh oil and he said it was serviced not long ago,
i have been told it has sti upgrades and it does have a sti tmic
also he said it has a stage 2 rally head or something
dont know if he knows what hes talking about,
this is the engine bay
i really dont know much about these scoobys, new to this
thanks for the reply bud
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Old 24 Apr 2011, 10:12 AM   #4 (permalink)
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Re: keeps holding back

you need to find out if it has been remapped or had the ECU changed to compensate for the mods that have been carried out, decat/air filter doesnt look standard/heads(stage2) etc
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Old 24 Apr 2011, 10:16 AM   #5 (permalink)
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Re: keeps holding back

how would i find out this mate?
would checking the psi on the turbo gauge help?

my dad said it seemed like fuel starvation but if this is the case wouldnt it happen in 1st and 2nd when in high revs?

Last edited by ashbuster; 24 Apr 2011 at 12:40 PM.
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Old 24 Apr 2011, 12:41 PM   #6 (permalink)
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Re: keeps holding back

when im in 3rd the psi goes to 20 thats when it happens
in 2nd it goes to around 18 and is fine

ifi t helps this is what the seller said it has had done
sti upgrades and mods turbo gauges turbo timer sti intercooler high lift cams stage 2 rally head new clutch forge dump valve samco pipes 4" scorpion stainless steel right through form manifold to back with stainless steel de-cat

turbo timer isnt wired up tho and i dont have a clue how to

Last edited by ashbuster; 24 Apr 2011 at 01:56 PM.
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Old 24 Apr 2011, 03:37 PM   #7 (permalink)
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Re: keeps holding back

Would get it only a rolling road with a good reputation for scoobs and troubleshoot from there. If the mods and map where not done right it might cost u an engine.
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Old 24 Apr 2011, 03:44 PM   #8 (permalink)
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Re: keeps holding back

wheres the best place mate and prices
im in the west mids brownhills/walsall area
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Old 24 Apr 2011, 03:54 PM   #9 (permalink)
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Re: keeps holding back

any chance it could be fuel filter? or fuel pump
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Old 24 Apr 2011, 05:19 PM   #10 (permalink)
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Re: keeps holding back

Might possibly be one of those. Fuel filters have been known to cause issues if not changed regularly
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Old 24 Apr 2011, 05:52 PM   #11 (permalink)
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Re: keeps holding back

for the price of it i may aswell change it and see what happens, will narrow the search abit more,
could the knock sensor cause this too

and should this car be run only on high octane?

by the way thanks for the replies guys
just thought i should add, its not like a hesitation its like a strong jerk back and go again, revs drop right down

Last edited by ashbuster; 24 Apr 2011 at 05:59 PM.
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Old 24 Apr 2011, 06:14 PM   #12 (permalink)
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Re: keeps holding back

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Old 24 Apr 2011, 06:42 PM   #13 (permalink)
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Re: keeps holding back

thanks mate
ive been reading about and it sounds like boost cut,
i read that boost cut is like hitting a brick wall in high gears
this is whats happening with me
as soon as my gauge reads 20 psi wich is maxed it jerks hard like hitting a wall
is there anyway i can turn this boost down?
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Old 24 Apr 2011, 10:17 PM   #14 (permalink)
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Re: keeps holding back

hey guys
just had my mates in the car and as soon as it happened he said its overboosting,
anyway to turn this down?
can i adjust it with my actuator?
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Old 25 Apr 2011, 08:31 PM   #15 (permalink)
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Re: keeps holding back

Another thing that can cause that stuttering is the neutral position switch on the gearbox. Mine has gone and it plays up in a similar way, what happens is the switch fails on acceleration sometimes and tells the ecu that it is in neutral when it isn't. This causes the revs to drop and then correct again almost instantly. I found a new one on ebay for £46, only thing is you have to drop the gearbox slightly to change.
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