Weird boost!!
23 November 2004, 08:06 AM
#1
Weird boost!!
Just noticed today on my MY01 with PPP that (especially in fourth) on just off full throttle that the boost does something weird...
It goes up to about 12/13 psi at about 2700/2800 revs then just at 3000 drops to 6.9 psi.... applying full throttle it then goes back up to about 20 psi by 3500 / 4000
Then knocklink is quiet but i did notice that at about this time on the SECS monitor the kock correction goes to 9.0 degrees???
Is there a problem is is it just the map? It is noticable (but only just and being as I;ve had the car 3 years it is subtle but noticable to me)...
It goes up to about 12/13 psi at about 2700/2800 revs then just at 3000 drops to 6.9 psi.... applying full throttle it then goes back up to about 20 psi by 3500 / 4000
Then knocklink is quiet but i did notice that at about this time on the SECS monitor the kock correction goes to 9.0 degrees???
Is there a problem is is it just the map? It is noticable (but only just and being as I;ve had the car 3 years it is subtle but noticable to me)...
24 November 2004, 08:55 AM
#6
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
It would affect any throttle position that creates positive boost pressure. The fact you're hitting 20psi is pretty good proof that something somewhere is blocked/clogged. I don't know what the PPP max boost is, but it certainly isn't that high...
24 November 2004, 10:33 AM
#7
Mike... I have a seperate defi boost sensor fitted (from Psi 3) which is wired into the SECS monitor so it is showing true boost.
Judge.. the boost has always shown 20 psi and I have read before that is about the norm for a PPP car from previous posts I have read...
Judge.. the boost has always shown 20 psi and I have read before that is about the norm for a PPP car from previous posts I have read...
Trending Topics
24 November 2004, 12:14 PM
#8
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Are you sure about that? I can't speak for new age, but certainly the MY99/00 PPP boosted to around 16.5psi, just below fuel cut. 20psi would definitely trigger fuel cut on a classic...
24 November 2004, 01:23 PM
#9
Never had a problem with fuel cut just this happened in the last couple of days... Always read that much and that is PEAK and only reaches that between about 4 / 5 rpm then tails off
see http://bbs.scoobynet.co.uk/showthrea...+boost+reading i posted some time ago and http://bbs.scoobynet.co.uk/showthrea...+boost+reading
Thanks for your help though.. definatly going to clean pipes and solenoid...
see http://bbs.scoobynet.co.uk/showthrea...+boost+reading i posted some time ago and http://bbs.scoobynet.co.uk/showthrea...+boost+reading
Thanks for your help though.. definatly going to clean pipes and solenoid...
24 November 2004, 02:26 PM
#10
Scooby Regular
Join Date: Jun 2003
Location: a very nice man :-) with one Fairy Token
Posts: 2,203
Likes: 0
Received 0 Likes
on
0 Posts
Non-expert view 
Are you saying the car is or feels slow as well as the boost indication or just that the boost does something funny? If the latter, surely this is correct? From what you say, it sounds like you have stopped accelerating and that is when the boost drops but climbs again when you floor it? That would sound normal to me as there is no longer the same load on the engine and you wouldn't see the same level of boost? For instance in lower gears, especially around town I actually see negative pressure as I have to lift slightly before changing otherwise the thing is just too damn quick (
). Sorry if I'm confusing things it just sounds normal to me (assume SECS is digital display - all this is much easier to see on a nice big Defi 
) oh and my 02 non PPP sti peaks at a smidge over 1.4 BAR (about 20.6 psi)
Are you saying the car is or feels slow as well as the boost indication or just that the boost does something funny? If the latter, surely this is correct? From what you say, it sounds like you have stopped accelerating and that is when the boost drops but climbs again when you floor it? That would sound normal to me as there is no longer the same load on the engine and you wouldn't see the same level of boost? For instance in lower gears, especially around town I actually see negative pressure as I have to lift slightly before changing otherwise the thing is just too damn quick (
). Sorry if I'm confusing things it just sounds normal to me (assume SECS is digital display - all this is much easier to see on a nice big Defi ) oh and my 02 non PPP sti peaks at a smidge over 1.4 BAR (about 20.6 psi)
24 November 2004, 04:20 PM
#13
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Wouldn't have thought a lambda sensor would cause this problem. Depending on gear and revs, even at 98% throttle, the fuelling would still be open loop, and therefore wouldn't be dependant on the lambda feedback.
It still sounds like a sticking wastegate solenoid...
It still sounds like a sticking wastegate solenoid...
28 November 2004, 03:47 PM
#15
Scooby Regular
Join Date: Dec 2001
Posts: 1,780
Likes: 0
Received 0 Likes
on
0 Posts
Fizz, how many times have you cleaned the solenoid, my MY01 took 2 attempts before it was working correctly.
I thought it was something else until i cleaned it again and all was fine.
Zippy
I thought it was something else until i cleaned it again and all was fine.
Zippy
01 December 2004, 09:56 AM
#27
Scooby Regular
Join Date: Dec 2001
Posts: 1,780
Likes: 0
Received 0 Likes
on
0 Posts
Fizz, have you cleaned ALL the pipes leading too and from the solenoid.
By that i mean removed them and cleaned them.On my first occasion this happened to me i had to remove ALL the pipes and clean them off the car.
I would be carefull about taking it to a main dealer as they probably wont have a clue.If it comes to it i would take it to a specialist as they will have seen this before, my local dealer took 8 hours plus to find out why my mates MY01 car wasnt boosting at all and only when i told them the actuator arm had probably come off they then found the fault, 10 minute fix and a new C washer and they where going to call in Subaru technical assist the following day,Ouch.
By that i mean removed them and cleaned them.On my first occasion this happened to me i had to remove ALL the pipes and clean them off the car.
I would be carefull about taking it to a main dealer as they probably wont have a clue.If it comes to it i would take it to a specialist as they will have seen this before, my local dealer took 8 hours plus to find out why my mates MY01 car wasnt boosting at all and only when i told them the actuator arm had probably come off they then found the fault, 10 minute fix and a new C washer and they where going to call in Subaru technical assist the following day,Ouch.
01 December 2004, 05:00 PM
#28
zippy,
yes... had all pipework off...
to be honest my dealer is pretty good (they run their own hill climb legacy and program the motek etc. on it)... they know what I have done and came to the same sort of conclusion about the solenoid. however it could actually be a failing solenoid as I completely lost boos twice on a track day in September...
hmm wonder if it's the actuator
yes... had all pipework off...
to be honest my dealer is pretty good (they run their own hill climb legacy and program the motek etc. on it)... they know what I have done and came to the same sort of conclusion about the solenoid. however it could actually be a failing solenoid as I completely lost boos twice on a track day in September...
hmm wonder if it's the actuator
01 December 2004, 05:46 PM
#29
Scooby Regular
Join Date: Jul 2003
Location: Out of darkness cometh light
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Wouln't have thought it would be the actuator. Even if the wastegate was permanently open, you'd still get boost. It would just take a hell of alot longer to build.
What about about the dump valve opening when it shouldn't? Or loose intercooler piping...?
What about about the dump valve opening when it shouldn't? Or loose intercooler piping...?