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Thread: Squealing on Boost

  1. #1
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    Default Squealing on Boost

    Hi all,

    About a month or so ago i needed to get the Accessory Drive Belt tensioner replaced on the MPS as the OEM had literally given in lol. The big give away was a rattling coming from the engine at low rpm's (like just as you engage the clutch without enough RPM). So that's all fixed now .

    I noticed about 2 - 3 days after it was installed though the car makes a squeal when on approximately 12+ psi (dashhawk figures) my friends think i could be a boost leak but car still pulls like a train and hasn't lost any pace. But recently the fuel pump has started to shit itself so i've been driving sensible for the last few weeks.

    Funnily enough i found a youtube video taken by Edgeautosports which has another Speed with the same noise as mine has, but obviously mine isn't as modified as this:

    Mazdaspeed 3 Gen2 GT3071R 2-4 gear pull - YouTube

    I've had a quick look for leaks but none of the viewable connections (FMIC) show any signs of leaking. Car still says it hits +/-18.5psi. Could it be an Intake leak???

    I'm not sure what it could be thought it could be the fuel pump struggling but no one has ever said anything about the MPS fuel pumps squealing before they die.

    I'll have another look in a week or so but if i still can find anything i might assume that it could be the Accessory Drive Belt Tensioner (since it isn't the OEM version).

    Thanking you
    James
    MPSX-treme

    2006 MPS Sports True Red - HP-F Mazedit tune + Other go fast bits - DGR Coilovers + Semi Slicks - Numerous Sure Motorsport Additions - Dashhawk

  2. #2
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    Default

    Did they replace the main belt when they did the pulley ?, you might be getting a bit of belt squeal as you are hitting peak torque, the replacement of the tensioner pulley shouldn't require disconnection of anything turbo related as the process can be done from the drivers side wheel well.

    My tensioner pulley has just gone as well, I'm getting that awful grinding / rattling sound on idle, the OEM assembly is ridiculously expensive though $229.00, and its sold as a complete replacement part, you cant service the pulley or the bearings independently, a new belt runs in at a pricey $85.00. Although there have been a fair bit of road works near work lately, so I am going to optimistically remove the assembly before buying a new one in the hope that maybe a small rock has jammed itself in there.
    Nearly all men can stand adversity. But if you want to test a man's character - give him power.
    Abraham Lincoln

  3. #3
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    Default

    Yeah don't get an OEM one i got an aftermarket one that the workshop sourced for me was a total of $189 installed.

    Can something on the boost side of things or even the intake side of things just get loose? I don't think a hole could just develop i've been over the pipe route 5 or 6 times and area's that get close to metal have been wrapped in rubber to prevent this and the entire cold side is heat wrapped but i'll have a look when i get a chance.

  4. #4
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    Check your LTFT values at idle, if they are a positive value it typically means you are running lean causing the ECU to add fuel, as the car is pulling air in post MAF under vacuum, indicating a leak.

    If your boost levels look OK it is either a very small leak only noticeable under boost, or the belt is slipping.

    Do you happen to know the part that your workshop was able to find for you, I dont want to pay for OEM if I can avoid it.

  5. #5
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    Yeah i got a service coming up soon i'll try and remember and ask them.

    What are the LTFT values and how do i get these to show on a dashhawk?

  6. #6
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    Sounds like you have the "kettle" as I termed it ie Turbo whistle...

    Sent from my Galaxy Nexus using Tapatalk

  7. #7
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    Default

    It's more like a kenne bell supercharger under the hood sounds insane but not sure if its an issue

  8. #8

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    Dashhawk will display long term fuel trim - you want this number to be +/- 4 when on the move but as said when at idle if this number always sits positive it may be a leak... Have you checked all your clamps for tightness? I've heard of the intake when it joins onto the tip making a squeaking/whistle noise before so maybe worth double checking everything

  9. #9
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    Ok everything before and after turbo is aftermarket so i'll have a look and maybe do the soap water trick i'll do the long term fuel trim thing too if the number sits at 0 or - is it ok?

    There isn't a way for scanning for a pre turbo leak is there via the dashhawk?

  10. #10
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    Should the LTFT number be in a % on the Dashhawk cause in my case its readings at 10.2% :S, if im reading the correct number i have a leak then.

  11. #11
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    If its +10.2 it is usually the sign of a leak at idle past the MAF sensor, a positive value indicates that the O2 sensor is reading slightly lean, so the ECU is adding fuel to achieve its desired 14.7:1 AFR, if you are seeing -10.2, it means the system is running slightly rich so the ECU is removing fuel to reach its stoichiometric target, a negative value is not uncommon on after market intakes and nothing to really panic about.

  12. #12
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    It's a positive value but its in a % reading so im not sure if im looking at the right figure... Setting the dashhawk up on the pc i selected the LTFT Bank 1 and Bank 2 plus andother LTFT option and only Bank 1 worked

  13. #13
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    Yep, thats the correct PID to be reading, if the DH cant read the sensor you have selected it will just show up as N/A on the display, happy hunting

  14. #14
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    Quote Originally Posted by MattMPS3 View Post
    Yep, thats the correct PID to be reading, if the DH cant read the sensor you have selected it will just show up as N/A on the display, happy hunting

    Fuuuuuuu.....! no worries i'll have a look and then another look and another look and then give it to someone to have a look lol.

    Also i haven't ask about the drive belt tensioner yet sorry but i will next time im done there
    MPSX-treme

    2006 MPS Sports True Red - HP-F Mazedit tune + Other go fast bits - DGR Coilovers + Semi Slicks - Numerous Sure Motorsport Additions - Dashhawk

  15. Default

    i had the same issue w while back. I traced it and found the exhaust end (the downpipe) which bolts into the turbo (i think with 5 bolts if i remember correct) was lose. check that area for exhaust suit. its a hard spot to reach and will make life heaps easier if the car is up on a hoist.
    if you trace that as a problem, you are better off replacing the turbo gasket and all 5 studs if you find this is the problem. the gaket i found was quite pricy at Mazda.

    ---------- Post added at 08:01 AM ---------- Previous post was at 08:00 AM ----------

    p.s. : a diagnostics tool will not be able to find this problem. so, dont be afraid to go old school - look, listen adn feel.

  16. #16

    Default

    My one at idle is about +4 %
    Up through the maf ranges it goes to 0.8% mainly.
    I prob just need to calibrate my maf via VT.

    Hows your LTFT when driving? Should be at normal levels...
    Allow car to idle for like 5 mins and see if LTFT is coming down.

    My one can read up to 7 or 8 but will drop down to 3 or 4 (at idle)

  17. #17
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    Quote Originally Posted by dar_vedar View Post
    i had the same issue w while back. I traced it and found the exhaust end (the downpipe) which bolts into the turbo (i think with 5 bolts if i remember correct) was lose. check that area for exhaust suit. its a hard spot to reach and will make life heaps easier if the car is up on a hoist.
    if you trace that as a problem, you are better off replacing the turbo gasket and all 5 studs if you find this is the problem. the gaket i found was quite pricy at Mazda.

    ---------- Post added at 08:01 AM ---------- Previous post was at 08:00 AM ----------

    p.s. : a diagnostics tool will not be able to find this problem. so, dont be afraid to go old school - look, listen adn feel.
    Thats Vedar, was your downpipe stock? Cause mine still is but i'm still not ruling it out. My thoughts atm is that it could be the Turbo Inlet or maybe the connection to the Core... I've checked everything else twice, still I'll take it to HP-F and they'll sort it out.

    Quote Originally Posted by kevstewart View Post
    My one at idle is about +4 %
    Up through the maf ranges it goes to 0.8% mainly.
    I prob just need to calibrate my maf via VT.

    Hows your LTFT when driving? Should be at normal levels...
    Allow car to idle for like 5 mins and see if LTFT is coming down.

    My one can read up to 7 or 8 but will drop down to 3 or 4 (at idle)
    Ok while driving the car reads between 7.4-9.2 and at WOT in 3rd 4th and 2nd sits at 8.6.

    Show what this shows is that when i can hear the leak my car is running like normal? lol

    Could the Fuel Pump be putting more fuel in to make the difference, or it can't work like that since the MAF is only reading 'X' amount of air and the Fuel Pump Reads that and then throws in enough fuel related to 'X'.

    Would air be escaping or being introduced?
    MPSX-treme

    2006 MPS Sports True Red - HP-F Mazedit tune + Other go fast bits - DGR Coilovers + Semi Slicks - Numerous Sure Motorsport Additions - Dashhawk

  18. #18

    Default

    That's a poor maf cal... When was your car tuned?
    Have you done mods since your tune?

  19. Default

    Quote Originally Posted by Bakis View Post
    Thats Vedar, was your downpipe stock? Cause mine still is but i'm still not ruling it out. My thoughts atm is that it could be the Turbo Inlet or maybe the connection to the Core... I've checked everything else twice, still I'll take it to HP-F and they'll sort it out.



    Ok while driving the car reads between 7.4-9.2 and at WOT in 3rd 4th and 2nd sits at 8.6.

    Show what this shows is that when i can hear the leak my car is running like normal? lol

    Could the Fuel Pump be putting more fuel in to make the difference, or it can't work like that since the MAF is only reading 'X' amount of air and the Fuel Pump Reads that and then throws in enough fuel related to 'X'.

    Would air be escaping or being introduced?

    Yup my car is stock standard. if you have a leak here you wudn'd really be losing power either.

  20. #20
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    Car was tuned by HP-F but since my Tune i've done FMIC, and upgraded Recirc Valve car was tuned over a year ago now, once i get fuel pump internals installed i'll be getting it retuned.


    I'll mention the exhaust to HPF as well so they can check everything .

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