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Thread: Boost Cut

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    I used to get it in stock form on my 6. Then I got ap loaded stage 1.. No more hesitation for me

  2. #22

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    I have something similar happen to me a few times when smashing through the gears at WOT, I was giving a RS265 a run all was fine then a slight hesitation like no power then boom power.
    Very strange

  3. #23

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    Yes it is odd. I have one theory, but it's only because I recently installed my FMIC and am still on stock tune. Perhaps the engine is expecting air before it's actually getting it, making it sometimes fall on it's face. It kinda makes sense, but not for those running the stock TMIC which I was. (admittedly it has gotten worse because of the FMIC though)
    Checking my spark plug gaps this afternoon to see if this might be contributing.. :/

  4. Default

    Quote Originally Posted by GibbA View Post
    Yes it is odd. I have one theory, but it's only because I recently installed my FMIC and am still on stock tune. Perhaps the engine is expecting air before it's actually getting it, making it sometimes fall on it's face. It kinda makes sense, but not for those running the stock TMIC which I was. (admittedly it has gotten worse because of the FMIC though)
    Checking my spark plug gaps this afternoon to see if this might be contributing.. :/
    you are also running a Cobb sf intake when you got the car, and now CS intake with box.
    I would say your now increased flow is causing these issues.

    EDIT: Plug gap check is a must

  5. #25

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    Yeah box not installed at the moment, because it doesn't fit with FMIC piping. Going to have to mod that to fit but yes, I get your point. Increased flow could be contributing to it...
    Will report back after checking the plugs.

  6. Default

    Quote Originally Posted by GibbA View Post
    Yeah box not installed at the moment, because it doesn't fit with FMIC piping. Going to have to mod that to fit but yes, I get your point. Increased flow could be contributing to it...
    Will report back after checking the plugs.
    common with Evo's , wrx's, Gti's.
    Mods which increase flow result in over boost.... because the stock maps are shite and the ecu just cant handle the over boost properly... so they spit the dummy lol!
    rusulting in sharp jolt/ cut.

    other times i have seen this is with an sr20 and coil packs on their way out.

  7. #27

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    so you're saying it's essentially a boost cut due to increased flow.
    Wonder if anyone's experienced it on a completely stock car, mods and tune wise..?

  8. Default

    Quote Originally Posted by GibbA View Post
    so you're saying it's essentially a boost cut due to increased flow.
    Wonder if anyone's experienced it on a completely stock car, mods and tune wise..?
    Im saying... maybeeeeee lol

  9. Default

    Also depending on the degree of boost spike will depend on the cut.
    I believe very large boost spike will actually do a temporary ignition cut. Which is what I think is happening

  10. #30
    Join Date
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    Default

    I have not had any boost cuts at all even with running a fmic...

    Sent from my GT-I9305 using Tapatalk 4

  11. Default

    Mazda dealers also do updatea on the ecu.
    possible that a particular update/revision had this issue?

    Most of what I say is probably crap... pretty much thinking out loud here.

  12. #32

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    Quote Originally Posted by auscer View Post
    I have not had any boost cuts at all even with running a fmic...

    Sent from my GT-I9305 using Tapatalk 4
    Yes but i'm talking stock tune as well...

    Anyway, plugs been gapped. They were pretty close though. @MPS2NV can chime in here
    Also had a look at the MAP sensor and it had a fair bit of crap in it so that was cleaned.

    Have to drive my car a bit more to really tell, had a few little instances of it, but nothing major like I have experienced. Will see as time goes on.
    --> 2008 Metro Grey Sports Pack Gen1 <--

    CS SRI ll CS TIP ll CS AB ll 2XS SSP ll 2XS FMIC ll SURE Anchors ll Enkei RPF1's 17x9 +45 ll Lamin-X Fog Tint ll DBA T3 4000 series ll Remsa pads ll Braided lines
    CP-E S2 RMM ll Hankook RS3 235/40/17 ll Forge V1 BPV ll Whiteline RSB ll AutoTech HPFP
    ll Spin-on Conversion ll Rear Diffuser
    DGR Coilovers ll LED Replacement lights ll "08-MPS" plates ll Cobb AP V3 (E85) ll CP-e TBE ll OCC






  13. #33

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    Quote Originally Posted by GibbA View Post
    You just described EXACTLY what happens randomly to me.
    I don't think it's "boost" cut because it's always coming onto boost that it happens (ie started to spool). Also not sure about fuel cut either, as I just upgraded my hpfp so there's plenty of pressure there, i've monitored it and it's good.

    I've heard this kind of thing referred to as "Hesitation" but as to what causes it, I have no idea. Sometimes it's worse than others, but it certainly gives me the feeling of "This really shouldn't be happening".

    I believe however that this is eliminated when a different map than stock is flashed. Further up in this thread it mentioned "CPE have recently added a fuel cut eliminator flash to their ensemble" but I doubt this is what's happening in the Cobb OTS maps if this in deed is the source of the issue?

    Who else gets this kick back that @sinsin described?
    Hey Alex

    What your describing can be due to a whole bunch of things:
    Spark plug blowout
    MAF cut
    Fuel Cut
    Boost Cut
    SWAS activated rich condition
    Boost leak
    Coil packs lacking tension

    Most of the conditions I listed are quite easy to fix, and mostly able to be fixed in the tune.
    Others require some small modifications to the car
    Eg
    Smaller spark plug gap, stretch coil packs etc

    If you log the condition I can help identifying the problem.

    Good luck.

  14. #34

    Default

    @rayd,

    Thanks for the input, I can cross off some, but cant log as I don't have my AP yet.

    I have been driving with SWAS both enabled and turned off and doesn't seem to make a difference
    MAF and MAP sensors have recently been cleaned and replaced properly, though not sure how these would relate to "blow out"
    Plugs were also checked and gapped today (were slightly larger than what they were meant to be)
    Coil packs also re tensioned today
    Fuel pump upgraded recently and FP monitored and was fine
    Boost leak I can't comment on, but sometimes it happens, sometimes not indicating that if it was boost leak related it'd be happening more often?

    I'm hoping that it can be cleared up with a tune, but even as Azza pointed out, the car had a much freeer flowing intake than the stock tune accounts for so this could be contributing as well.

    (Also i've never had a CEL)
    --> 2008 Metro Grey Sports Pack Gen1 <--

    CS SRI ll CS TIP ll CS AB ll 2XS SSP ll 2XS FMIC ll SURE Anchors ll Enkei RPF1's 17x9 +45 ll Lamin-X Fog Tint ll DBA T3 4000 series ll Remsa pads ll Braided lines
    CP-E S2 RMM ll Hankook RS3 235/40/17 ll Forge V1 BPV ll Whiteline RSB ll AutoTech HPFP
    ll Spin-on Conversion ll Rear Diffuser
    DGR Coilovers ll LED Replacement lights ll "08-MPS" plates ll Cobb AP V3 (E85) ll CP-e TBE ll OCC






  15. #35

    Default

    Quote Originally Posted by GibbA View Post
    @rayd,

    Thanks for the input, I can cross off some, but cant log as I don't have my AP yet.

    I have been driving with SWAS both enabled and turned off and doesn't seem to make a difference
    MAF and MAP sensors have recently been cleaned and replaced properly, though not sure how these would relate to "blow out"
    Plugs were also checked and gapped today (were slightly larger than what they were meant to be)
    Coil packs also re tensioned today
    Fuel pump upgraded recently and FP monitored and was fine
    Boost leak I can't comment on, but sometimes it happens, sometimes not indicating that if it was boost leak related it'd be happening more often?

    I'm hoping that it can be cleared up with a tune, but even as Azza pointed out, the car had a much freeer flowing intake than the stock tune accounts for so this could be contributing as well.

    (Also i've never had a CEL)
    Do you have DP installed aswell? If so this can cause a significant enough over boost for a fuel cut to occur. What Rpm is it occurring at?

    Hard to make a guess without a log , but once you get your AP I guess closure can be had

  16. #36

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    You may have a problem with your waste gate? If it isn't opening the valve on time or is not sensing the pressure built up from the exhaust fumes then it may be closing the valve and reopening ? Might not be but it might be on its way out lol I'm just throwing rocks at a tree for you now

    The fact that it comes on and then off then jolts is what's scary because it hasnt cause you a CEL...
    You can make it easier on yourself, don't wait for the AP go to a trusted mechanic or tuner and they can hook up the computer to your car and see wtf is going on with your fuel and air. If nothing shows up then you know it's gotta be hardware

  17. #37

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    I'd love to find out exactly what it is because I saw a friend of mine lose his Mps block while having this problem (might not be cos of this but he had the issue at the time as well as whatever else caused it)

  18. #38

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    Quote Originally Posted by sinsin View Post
    I'd love to find out exactly what it is because I saw a friend of mine lose his Mps block while having this problem (might not be cos of this but he had the issue at the time as well as whatever else caused it)
    Did he have any mods though (what were they if so?).
    @rayd no dp installed, and it generally is lower rpm (2-3.5k rpm) that i've noticed it when coming on boost.
    @sinsin your comment about the wastegate is an interesting idea, but the fact that it's changed with increased air flow speaks to me that is perhaps something more ECU related rather then mechanical related..
    --> 2008 Metro Grey Sports Pack Gen1 <--

    CS SRI ll CS TIP ll CS AB ll 2XS SSP ll 2XS FMIC ll SURE Anchors ll Enkei RPF1's 17x9 +45 ll Lamin-X Fog Tint ll DBA T3 4000 series ll Remsa pads ll Braided lines
    CP-E S2 RMM ll Hankook RS3 235/40/17 ll Forge V1 BPV ll Whiteline RSB ll AutoTech HPFP
    ll Spin-on Conversion ll Rear Diffuser
    DGR Coilovers ll LED Replacement lights ll "08-MPS" plates ll Cobb AP V3 (E85) ll CP-e TBE ll OCC






  19. #39
    Join Date
    Jun 2009
    Location
    Newcastle
    Posts
    1,413

    Default

    The OEM plugs at 90k are basically due to be binned, that being said the electrode errosion and deposits on the plugs indicate that everything is pretty good. A plug gap of .033" on 90k old plugs isnt surprising. The plugs were regapped to .027" but givin the age of them wouldnt get to excited over the process. I think it will be tune related issue which should'nt be a big deal once you get your AP

    as far stuffing around with the internals of the coils think thats wasting time, coil per plug systems wouldnt usually experience lack of coil saturation which is more of a problem on distributer type systems of older days.
    Although from my v8 boat experience, the same igniton system on a carburated chev would typically call for a small gap VS the .010" larger gap we would run on the EFI engines because of the effect on spark thermal efficiency due to the odvious fuelling methods.
    Last edited by MPS2NV; 07-09-2013 at 06:19 PM.
    Every man should have a V8 ute.....with a Chev badge.....and a Southern Cross sticker! Mods? What mods?

  20. #40

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    Short answer, it is KNOCK.

    Yes, got my AP yesterday, only really done highway driving on it, but flashed a stage 1 SF+TIH+IC 98 map on it.
    Was monitoring boost (all good) AFR (mainy all good, though a bit rich at times) and KR.
    When i'd stick my foot down and i felt the jolt, it was nearly ALWAYS knock.
    Ranging from 0.35-0.7-2.3-3.5 and 5.4 was the worst I saw at one particular time which made me quite worried.
    I will strive to run a log and record this event, but would like some advice on which parameters I should be recording please?
    --> 2008 Metro Grey Sports Pack Gen1 <--

    CS SRI ll CS TIP ll CS AB ll 2XS SSP ll 2XS FMIC ll SURE Anchors ll Enkei RPF1's 17x9 +45 ll Lamin-X Fog Tint ll DBA T3 4000 series ll Remsa pads ll Braided lines
    CP-E S2 RMM ll Hankook RS3 235/40/17 ll Forge V1 BPV ll Whiteline RSB ll AutoTech HPFP
    ll Spin-on Conversion ll Rear Diffuser
    DGR Coilovers ll LED Replacement lights ll "08-MPS" plates ll Cobb AP V3 (E85) ll CP-e TBE ll OCC






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