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Engine Stalls at low revs

tazataza Member Posts: 64 ✭✭

Engine starts first time, leave engine running RPM approx. 600 after a while just stalls   Starts back up fine same again happens if I keep the revs above 900rpm its OK VOLVO PENTA 5.7Gi- G

Engine Serial No 4012215965

Out Drive DPS-A No 4202203870

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    Dream_InnDream_Inn Member, Moderator Posts: 7,561 mod
    Sounds like a possible IAC valve issue.  I'm not too familiar with the Volvo, but I know on the Mercs the valve is located on the aft side of the throttle body.  Couple allen head bolts and one hose to remove and it's off.

    Dream 'Inn III -- 2008 400 Express

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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    you're starving it of something... could be air (and the IAC a prime candidate as the issue) or it could be fuel (dirty filters-doesn't matter how old they are if the fuel is contaminated).  Also, check for a vacuum leak. 
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    tazataza Member Posts: 64 ✭✭
    Cheers Guys
    But why only at low Revs, runs great above 900rpm
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    Liberty44140Liberty44140 Member Posts: 4,331 ✭✭✭✭✭
    When the IAC went bad on my 310's 5.0 Merc it was intermittent at first but always hit me when I was at idle or neutral. 
    07' Cruisers 390 (Previous Rinker's: 06' 342EC & 01' 310FV)

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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    at idle your engine's throttle body blade(s) are closed- not enough air making it past the plunger/passage on your IAC to allow it to run.  when the blades are open on your throttle body, it gets plenty enough.  the idle air control's purpose is to regulate the air, and allow enough to pass to maintain idle (600~650rpm)... they can get pretty nasty and gunked up, which limits its ability to provide the air even if the plunger/needle is fully extended from the seat. 
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    MarkBMarkB Member Posts: 3,962 ✭✭✭✭✭

    Yeah, 212rowboat has it right, you're starving it. If it doesn't bother you, you could always just adjust idle to keep it above the stall point (although I wouldn't want it to idle anymore than 700).

    Boat Name: King Kong

    "Boat + Water = Fun"

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    TazTaz Member Posts: 62 ✭✭
    Guys
    replaced IAC Valve and still stalls 
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    TazTaz Member Posts: 62 ✭✭
    Also checked fuel pressures
    low pressure pump 18psi. Manual says 8psi
    high pressure pump 52psi Manual says 50 to 60 psi
    i also checked fuel regulator and fitted the e Clip mod that Volvo recommend

    but still stalls at 600 rpm
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    212rowboat212rowboat Member Posts: 2,591 ✭✭✭✭✭
    way too much fuel at idle... bad regulator.  is this engine tbi or mpi?  
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    TazTaz Member Posts: 62 ✭✭
    My Engine has the fuel rail with 8 ejectors,EFI Engine
    Going back the boat this Friday with a new Fuel Regulator 

    will keep you all posted






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    TazTaz Member Posts: 62 ✭✭
    Fitted new regulator and it still stalls at idle
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    rasburyrasbury Member Posts: 8,242 ✭✭✭✭✭
    And the filters?
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    rasburyrasbury Member Posts: 8,242 ✭✭✭✭✭
    How long since plugs and stuff?
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    aero3113aero3113 Member Posts: 8,811 ✭✭✭✭✭
    It's possible your RPM gauge is faulty,when reading 600 it could actually be lower causing the engine to stall. 
    2008 330EC
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    tazataza Member Posts: 64 ✭✭

    Guys

    Plugs,Dissy,Rotor,Oil,filters,Leads all been replaced  600rpm is the correct speed, 600RPM on dash gauge also on Rinda Scan tool showing the same

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    rasburyrasbury Member Posts: 8,242 ✭✭✭✭✭
    cleaned flame arrestor? Have not heard that mentioned....beyond that my mind says your not getting enough juice/voltage to the plugs at low rpm or a fuel restriction...new boat to you? Looks like your a new member....ask PO if this has been an issue in the past?
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    rasburyrasbury Member Posts: 8,242 ✭✭✭✭✭
    and I'm very new to figuring this stuff out and usually equate to a car which I know does not always apply---if you have a bad/failing alternator is it possible it is draining the batteries/electrical system so at low rpm it is not getting enough juice to keep it running? Or bad batteries? Does the alternator provide power to the engine or does it go through the battery and then the engine? Just talking "out loud" here looking for ideas. He has done everything I have seen in other posts with similar issues...
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    dalekdalek Member Posts: 259 ✭✭✭
    With reference to Rasbury's posts above, is it possible you could try running the engine with the shore power plugged in and the charger on?
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    rasburyrasbury Member Posts: 8,242 ✭✭✭✭✭

    someone will chime in that knows way more than me...I'm probably way off base as normal!

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    tazataza Member Posts: 64 ✭✭

    Replaced the arrester with a new one, and I have had the shore power connected, battery voltage is OK and alternator is fine.

    Going the boat this weekend to have another look

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    dalekdalek Member Posts: 259 ✭✭✭
    Did your scan tool show sensible air intake and coolant temperatures?
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    raybo3raybo3 Administrator Posts: 5,459 admin
    Is it possible that the neutral safety switch is out of adjustment????? 
    2002 342 Fiesta Vee PC Point Of Pines YC Revere MA. popyc.org     raybo3@live.com
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    TazTaz Member Posts: 62 ✭✭
    i sent the new faulty fuel cell back and they sent me a new one back, fitted the fuel cell and so far it's been running OK not stalled once, going back tomorrow to try it again, The pressure readings for the new fuel cell are
    Low Pump 10psi Old pump 18psi
    High Pump 50 psi Old pump 54 psi 

    My thinking is to much fuel being delivered and flooding the Engine at low revs ?????
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