tried a search on boost problems to no avail...
08 January 2007, 08:37 AM
#1
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tried a search on boost problems to no avail...
as above lol. ive had the scoob (uk turbo my99) for around 5/6 weeks now, and i have noticed a problem on boost.
for example im cruising in top gear at 70mph and i put my foot down... car boosts as expected but you here the turbo spool up, then stop, then spool up again...
bit strange eh? thing is i dont think it may be fuel cut because it doesnt feel like hitting a "brick wall", its like putting your foot down, then taking it off slightly then putting it back on, say every 1sec 1.5sec for example.
i definatley know it isnt a slipping clutch, as i had that in my old wrx, where the revs cained upwards and the car went knowhere. the car speeds up, but its like it stops boosting, then boosts again, then stops... etc etc.
from a standing start, say to 60mph, no problems at all, or not that are noticeable to me anyway. i think it may be a boost problem, but im not sure on the specifics of it, and hoped that with all the details ive given, somebody may have had a similar problem and/or know the answer.
for the record, the car seems pretty much standard, it had a full service at scoobybits on friday, ie new cambelt, oil, oil filter, even a new radiator. this hasnt solved the problem.
one point though to digest is there was a little gauge under the bonnet, after asking jason and chris at scoobybits, they told me it was a fuel regulator, or something or another. could this be my problem?
thing is currently im trying to save up to get a remap and a full decat for the scoob, so im not really caning it everywhere, more sensible pootling about, so would i be ok driving the car for a few months, or from everything ive tried to explain, would i be best maybe going somewhere like scoobyclinic and having a rolling road run done to source the problem.
sorry for all the waffle, ive tried to be as specific to the problem as possible.
help suggestions welcome
cheers... andy
for example im cruising in top gear at 70mph and i put my foot down... car boosts as expected but you here the turbo spool up, then stop, then spool up again...
bit strange eh? thing is i dont think it may be fuel cut because it doesnt feel like hitting a "brick wall", its like putting your foot down, then taking it off slightly then putting it back on, say every 1sec 1.5sec for example.
i definatley know it isnt a slipping clutch, as i had that in my old wrx, where the revs cained upwards and the car went knowhere. the car speeds up, but its like it stops boosting, then boosts again, then stops... etc etc.
from a standing start, say to 60mph, no problems at all, or not that are noticeable to me anyway. i think it may be a boost problem, but im not sure on the specifics of it, and hoped that with all the details ive given, somebody may have had a similar problem and/or know the answer.
for the record, the car seems pretty much standard, it had a full service at scoobybits on friday, ie new cambelt, oil, oil filter, even a new radiator. this hasnt solved the problem.
one point though to digest is there was a little gauge under the bonnet, after asking jason and chris at scoobybits, they told me it was a fuel regulator, or something or another. could this be my problem?
thing is currently im trying to save up to get a remap and a full decat for the scoob, so im not really caning it everywhere, more sensible pootling about, so would i be ok driving the car for a few months, or from everything ive tried to explain, would i be best maybe going somewhere like scoobyclinic and having a rolling road run done to source the problem.
sorry for all the waffle, ive tried to be as specific to the problem as possible.
help suggestions welcome
cheers... andy
08 January 2007, 08:58 AM
#2
Sounds like the boost duty is too high for the target boost setting.
When in high gears boost will spool quicker, if the duty is too high then the ECU will try to pull the boost back to prevent overboost. This will cause the surging you describe as the electronics and mechanics play cat'n'mouse.
It's quite common for this to happen on cars that have been remapped but havn't had the chance to run in 5th i.e it's fine on the RR tune which will be done in 4th, but plays up on the way home on the motorway.
If your car hasn't been remapped then it may be a partially clogged vacum pipe. Clean out the small bore pipes that connect to the turbo and actuator (either side of the small plastic T-piece).
There is a small brass restrictor in one of these pipes that may be partially clogged. The smaller the hole the higher the boost/boost spike, so it needs to be clean.
When in high gears boost will spool quicker, if the duty is too high then the ECU will try to pull the boost back to prevent overboost. This will cause the surging you describe as the electronics and mechanics play cat'n'mouse.
It's quite common for this to happen on cars that have been remapped but havn't had the chance to run in 5th i.e it's fine on the RR tune which will be done in 4th, but plays up on the way home on the motorway.
If your car hasn't been remapped then it may be a partially clogged vacum pipe. Clean out the small bore pipes that connect to the turbo and actuator (either side of the small plastic T-piece).
There is a small brass restrictor in one of these pipes that may be partially clogged. The smaller the hole the higher the boost/boost spike, so it needs to be clean.
08 January 2007, 11:09 AM
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waste gate problem...its overboosting....Most common cause the waste gate actuator has become detached from the "arm" on the turbo charger....or the waste gate actuator solenoid is fubar.
the wastegate actuator is connected to the wastegate via an arm....kinda like a piston....when the piston moves it operates the waste gate......is 99 still classic i forget.....however for some reason subaru used a pants spring clip to connect the "piston" to the waste gate......in 70% of overboosting cases (im no expert but i was the first petrol head where i live to fix the scooby for less than 35 quid an hour) the spring clip has come off the waste gate arm and the actuator is moving without any effect on the wastegate.
the wastegate actuator is connected to the wastegate via an arm....kinda like a piston....when the piston moves it operates the waste gate......is 99 still classic i forget.....however for some reason subaru used a pants spring clip to connect the "piston" to the waste gate......in 70% of overboosting cases (im no expert but i was the first petrol head where i live to fix the scooby for less than 35 quid an hour) the spring clip has come off the waste gate arm and the actuator is moving without any effect on the wastegate.
Last edited by thedeester1; 08 January 2007 at 11:37 AM.
08 January 2007, 02:19 PM
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well with me not being mechanically sorted as of yet, if i took it too somewhere like scoobyclinic, would they be able to help? as i said before, i asked jason at scoobybits, and from how i described it to him, he thinks by having it on a rolling road, would determine the exact point of any blockage etc. i dont wanna end up forking out pennies, when as you say it could be a blockage in a pipe, or over boost which the ecu is kind of retarding...
mainly though if i dont cane her it is safe to drive, because it tends to happen in higher gears at higher than "legal" speeds... third gear being the lowets real noticeable one
andy
mainly though if i dont cane her it is safe to drive, because it tends to happen in higher gears at higher than "legal" speeds... third gear being the lowets real noticeable one
andy
08 January 2007, 03:54 PM
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I had a similar problem on mine. Also a uk 99 turbo. I cleaned parts, replaced parts, tried different parts. Here's the bitch. Changed to a different fuel, problem went away. I was using 'normal' fuel originally, thought with it being uk it'd be fine. Changed to V power, she loves it. She drinks it like it's going out of fashion. The only other issue I have is an iffy lamda sensor. I get a bit of hesitation when cold. Unplug it and this goes away. Whether a new lambda would fix this I do not know. So if anyone does know, let me know.
Hope this maybe helps a bit.
Chad!
Hope this maybe helps a bit.
Chad!
08 January 2007, 04:31 PM
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I had a similar problem on mine. Also a uk 99 turbo. I cleaned parts, replaced parts, tried different parts. Here's the bitch. Changed to a different fuel, problem went away. I was using 'normal' fuel originally, thought with it being uk it'd be fine. Changed to V power, she loves it. She drinks it like it's going out of fashion. The only other issue I have is an iffy lamda sensor. I get a bit of hesitation when cold. Unplug it and this goes away. Whether a new lambda would fix this I do not know. So if anyone does know, let me know.
Hope this maybe helps a bit.
Chad!
Hope this maybe helps a bit.
Chad!
i think, or at least hope, it may be a blocked pipe, and not something to do with boost control. i could try doing an ecu reset, but if i got a fault code up, what would i do then?
andy
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