Overboost?

[rebmulp]

Is overboost protection like a rapid fluttering sensation sorta juddering? Only in my last T5 it sorta cut then came back, but in the present t5 its like a juddering. It has a rica 304 remap. I have tried fitting an MBC today it is turned down to minimum and it is better but still seems to overboost (if thats what it is doing). I am not an expert in these matters by any stretch. Any help would be appreciated. I was thinking that the wastegate is staying shut too much could it be an actuator fault?? HELP!

[T5frankie]

Having more boost will show up crappy spark plugs by getting spark blow out this causes the same problems as you describe

[rebmulp]

Plugs it is then. For a start.Thanks for that. It has been baffling me because the afm boost gauge is not showing high boost.The one on yhe clocks shows about 3/4

[p fandango]

thats not the overboost then, the end of white on the factory gauge is around 15psi which is when the boost cut comes in. Factory boost cut is very aggressive & you'd certainly know when you hit it, brown trouser moment lol

[T5frankie]

you wont have overboost protection on a re-mapped ecu anyway

[p fandango]

you wont have overboost protection on a re-mapped ecu anyway
some raise it, some remove it altogether

[rebmulp]

OK I will post results when plugs are done.Ignorance is bliss Thanks guys.

[rebmulp]

nice 1
































Nice 1 seriously many thanks!!Just been round the village plugs have done it boosting to 0.8 bar in 2nd. Is it worth turning it up do ya think?

[T5frankie]

nice 1


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i run mine at 1.5 bar mate just dont floor it till after 4000rpm,



























Nice 1 seriously many thanks!!Just been round the village plugs have done it boosting to 0.8 bar in 2nd. Is it worth turning it up do ya think?


i run mine at 1.5 bar mate just dont floor it till after 4000rpm,

[rebmulp]

I will gradually turn it up. Mine is an auto so Idont want to go too far. Also has standard boost hoses/balloons Thanks again for the guidance.

[manback]

even when mines running standard 9psi on the MBC its cutting the iginition to the car between 3-4k.

well i assume its the ignition cutting, or turbo surge or the spark plugs failing or what ever is really happening!

is anyone else experiencing this?

[p fandango]

even when mines running standard 9psi on the MBC its cutting the iginition to the car between 3-4k.

well i assume its the ignition cutting, or turbo surge or the spark plugs failing or what ever is really happening!

is anyone else experiencing this?
the boost/MAF cut on a standard ECU is like hitting a brick wall, VERY aggressive & you'll certainly know it if its cutting in. When i'm home i'll post a vid of BT hitting it on the 1/4

[si850r]

well i ve cleaned my maf today with electric contact cleaner, cleaned my idle control valve and where it connects to the engine with carb cleaner and my car still feels like its holding back...It boosts then dont then boosts again .It s pickling me now...

[smithy]

well i ve cleaned my maf today with electric contact cleaner, cleaned my idle control valve and where it connects to the engine with carb cleaner and my car still feels like its holding back...It boosts then dont then boosts again .It s pickling me now...

bcs mate or actuator not tight or nackered

[p fandango]

BT (burgundy 854) hitting the MAF/boost limit

http://www.youtube.com/watch?v=Ce1QoS3XpG4

[si850r]

bcs mate or actuator not tight or nackered
I adjusted the actuator and the boost is coming in earlier (about 2500 now)
so I aint to sure if its that, the bcs is a maybe..Im gonna whip the plugs out and see what they look like...Any idea on the spanner size for them is it a 14mm?

[manback]

the boost/MAF cut on a standard ECU is like hitting a brick wall, VERY aggressive & you'll certainly know it if its cutting in. When i'm home i'll post a vid of BT hitting it on the 1/4

So what's the solution?

[p fandango]

So what's the solution?
turn the boost down

[manback]

turn the boost down

It's already at 9psi! I may as well keep the Volvo controller on!

[smithy]

It's already at 9psi! I may as well keep the Volvo controller on!

you should be able to run it at 16 psi no probs what plugs are you using

[manback]

No idea. I imagine they are cheap ones. Is that a factor?

[claymore]

No idea. I imagine they are cheap ones. Is that a factor?

Very much so, use standard Volvo plugs

[manback]

Very much so, use standard Volvo plugs

can anyone explain this for me, surly the fuel can either ignite or not ignite.
so if your saying im not igniting fair doos, but theres no half way house with this is there?

[Yorkshiresxi]

Sorry to reopen a old post...but did you ever sort this problem out..as mines still doing in.plugged in a boost gauge tonight i am out 11psi, on what is ment to be a 280 mapped ecu...now floor it and its ok..give mid power and she splutters some times..when she splutters floor it and its ok..could it be plugs..i fitted new ngk ones about 3 months ago and leads.
thanks

[T5frankie]

Sorry to reopen a old post...but did you ever sort this problem out..as mines still doing in.plugged in a boost gauge tonight i am out 11psi, on what is ment to be a 280 mapped ecu...now floor it and its ok..give mid power and she splutters some times..when she splutters floor it and its ok..could it be plugs..i fitted new ngk ones about 3 months ago and leads.
thanks

you sure it's mapped?

[Yorkshiresxi]

I cant be 100% no, i will video the cut out as its not boost cut as such as its as if its fuel cut etc...i need to change a few vac lines so manybe that will help

[t5lover]

Sorry to reopen a old post...but did you ever sort this problem out..as mines still doing in.plugged in a boost gauge tonight i am out 11psi, on what is ment to be a 280 mapped ecu...now floor it and its ok..give mid power and she splutters some times..when she splutters floor it and its ok..could it be plugs..i fitted new ngk ones about 3 months ago and leads.
thanks
Well I would get the codes checked first could be the tps doing it as we found out on jelt5 yesterday put a 3.0L throttle body on it's and all is clear, then put standard volvo plugs in and see what she does fella :)

[LiamT4]

you sure it's mapped?

remember, mine has been mapped and its struggling to get to 13psi.

[floppy69]

it sounds reminiscent of the sort of cut i was getting with an ecu that was supposed to be chipped and after fitting an ecu from hml no cut running up to 17-19 psi of boost with stock plumming...could be the ecu!!

[merc85]

Ignition Leads?? this was what was causing my similar problem.

[T5frankie]

it sounds reminiscent of the sort of cut i was getting with an ecu that was supposed to be chipped and after fitting an ecu from hml no cut running up to 17-19 psi of boost with stock plumming...could be the ecu!!

mate its hlm not hml "Hamish Lindsey Motorsport" lol

[Yorkshiresxi]

I am kinda thinking of sending me old T5 ecu for a postal remap then i know for sure its been done then...i am running 12 psi at the moment, but need to put my boost gauge somewere and try and find somewere to put the pipe through the bulk head

[T5frankie]

I am kinda thinking of sending me old T5 ecu for a postal remap then i know for sure its been done then...i am running 12 psi at the moment, but need to put my boost gauge somewere and try and find somewere to put the pipe through the bulk head

standard is 10psi mate, mine when mapped went up to 12

[Yorkshiresxi]

Yeah didnt know if i should crank the MBC up and see if she will run at 14 or something...see if my problem is still there or gets worse

[T5frankie]

I had the same problem it xas crap leads and plugs

[LiamT4]

I'm guessing you have an s70/v70 as you don't have a boost gauge.
If its a fueling issue then i very much doubt that turning the mbc up would help it, apart from seeing if it will boost higher and show up the problem more.

How "jerky" is it? Is it a splutter or more progressive?

I say this as mine has got a boost problem, but its very progressive, just like you can feel the boost coming on and off. If its like mine then i doubt it would be plugs, leads etc and more like a bcs or actuator problem

[Yorkshiresxi]

No its a 850 i have...i have a boost gauge yes. Didnt do it at all this morning on the way to work and i havnt touched the MBC or anything.
I have replaced the plugs, leads, cap, rotor, etc about a month ago.
I have a 16T to go on this week or next now with a actuator so maybe see if its any better then..as for strength..its mild..its like someone cutting the fuel for a split second...its not harsh at all.
Like said when it does it..if i floor it at the same time it goes away..its as if its only there when your loading up and holding the boost rather then if you floor it and make it work its fine.
Example..over taking a car the other morning...long open road, just put the power down half way..but full boost and she pulls out..starts to go..splutter, goes, splutter, goes splutter, pulls in and i floored it, fine..slowed down, go again, splutter go splutter slamed it down fine all the way to the red line...
maybe something i am going to have to live to deal with since fitting the MBC.
Or maybe try a different MBC maybe
Call me crazy...half of me wants to crank the MBC up that much that it does boost cut out then i know what that feels like, and i will know its not that now - but dont want to bend a rod .lol
Thanks chaps