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348 rough running need info

Discussion in 'Technical Q&A' started by MDshore348, Feb 26, 2006.

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  1. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
    2,460
    Maryland
    Full Name:
    Darron
    #1 MDshore348, Feb 26, 2006
    heres my situation. put the car into storage over the holidays . didnt run it for 6 weeks of cold weather. drove it home a few weeks ago , noticed it lagging at acceleration. figured it needed some driving, the more i drove the worse it seemed to get. parked it. changed out the aftermarket ecu chips back to stock . idles lower sounds worse. no popping or sputtering, just sounds consistantly rough. pulled plug wires inspected them, one looked a little green at the contact, cleaned it.no difference. pulled the plugs, nice and dry , tad white at the tip . compression checks out ok consistant across within 10lbs max spread.
    ECU, just noticed that the 5/8 light doesnt light up at start up , it used to .. i cant remember when exactly i last saw it .

    now what. ?
     
  2. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
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    #2 No Doubt, Feb 26, 2006
    Switch your ECUs from left to right. Does your 5/8 light now show up during your start up test?
     
  3. Dr_ferrari

    Dr_ferrari Formula 3
    Consultant Professional Ferrari Technician

    Nov 2, 2003
    1,073
    Pocono Sportscar
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    Jim McGee
    #3 Dr_ferrari, Feb 26, 2006
    Is you 5/8 bank running? is the 5/8 bank manifold hot when running?

    regards, Jim
     
  4. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
    2,460
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    Darron
    #4 MDshore348, Feb 26, 2006
    ill se tomorrow a.m. when i swap out ecu 's .
     
  5. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
    2,460
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    Darron
    #5 MDshore348, Feb 28, 2006
    update, pulled codes, nothing , well it reads 4444 which means no probs showing...
    it will idle for a few minutes, then seesaw between rough and normal idle ... ,1 second rough, 3 seconds normal , etc...
    all connections have been checked and rechecked.
    do ijust start replacing the 02 and lambda sensors now?
    ps both lights 1/4 and 5/8 work properly , i was just mistaken when i made the previous post.
     
  6. BT

    BT F1 World Champ
    Lifetime Rossa

    Mar 21, 2005
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    Bill Tracy
    #6 BT, Feb 28, 2006
    I would replace the O2 sensors. They are cheap to replace and are items that wear out anyway. If they aren't bad now, they likely would be within a few years.
    BT
     
  7. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
    2,460
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    Darron
    #7 MDshore348, Feb 28, 2006
    ill try that today ..
     
  8. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
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    #8 ernie, Feb 28, 2006
    Try checking the connections for your MAFS. Make sure they are clean, connected properly and that the wires are in good shape. You may also want to have a look inside the MAFS to see if everything is clean inside.
     
  9. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
    2,460
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    Darron
    #9 MDshore348, Mar 9, 2006
    checked everything above , and replaced 02 sensors with the 15727 universals .
    still the same. a consistant burbling not exhaust popping , while revvving and at idle. it revs fine, just has that sound . at higher rpms, it sounds smooth , with the undertone of the burbling through the exhuast. next ?
     
  10. No Doubt

    No Doubt Seven Time F1 World Champ

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    #10 No Doubt, Mar 9, 2006

    OK, she idles fine when cold, yes?

    Then your thermostat opens, cooling fans kick on, and the idle gets rough?

    Or does it get rough before the cooling fans kick on?

    Right when cold, you've got the cold-start system engaged (extra fuel/air) and the O2 sensor should be ignored.

    As the car warms up, the exhaust ECU should send a signal that the car is warm enough to trust the O2 sensors. The cold-start system should be disengaged at this point, but the temp won't be hot enough (yet) to have kicked on the cooling fans or open the thermostat (not sure on timing here).

    If your rough idle starts *prior* to the cooling fans kicking on, but not when the engine is cold, then it would likely be an O2 (or O2 grounding problem) sensor or MAF.

    But if the rough idle starts while the engine is still cold, then you can rule out the O2 and MAFs being the direct cause of the rough idle.

    If the rough idle starts only when the cooling fans kick on, then it could be an alternator issue, a wiring issue (like a short to ground in a fan), or a water pump issue.
     
  11. MDshore348

    MDshore348 Formula 3

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    #11 MDshore348, Mar 9, 2006
    nope -rough burble hot or cold.. at start up , after warm start up .new major service jan 05
     
  12. No Doubt

    No Doubt Seven Time F1 World Champ

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    #12 No Doubt, Mar 9, 2006
    You always hear the rough burble? There's no point where it idles fine?
     
  13. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
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    #13 MDshore348, Mar 9, 2006
    you can always hear it in the background of the revs. but at low it is more distinctive .
     
  14. No Doubt

    No Doubt Seven Time F1 World Champ

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    #14 No Doubt, Mar 9, 2006
    Are there two different issues? A rough idle and a burbling noise?
     
  15. PAP 348

    PAP 348 Ten Time F1 World Champ
    Lifetime Rossa Owner

    Dec 10, 2005
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    #15 PAP 348, Mar 9, 2006
    A waterpump issue? What the hell do you mean by that man? Lol :p
     
  16. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
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    #16 MDshore348, Mar 9, 2006
    for all knowledgable ears i have a mpeg clip i can email you . pm me with your email today. to see if you can guess the noise ?!
     
  17. MDshore348

    MDshore348 Formula 3

    Dec 24, 2004
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    #17 MDshore348, Mar 20, 2006
    after all this headache... it was a bad spark plug! funny , when i initially pulled the plugs when it had intermittant rough sound , they all looked pretty dry and white , then i began to run it everytime i did something else to try to solve it. finally at the end when it was consistantly rough sounding , i isolated it to #3 and pulled the plug . it was wet and fouled. thinking it was something i couldnt fix, i took it to the shop .in the end a change of plugs was all it needed. go figure. champion plug went bad on the inside of the plug. wouldve never thunk it!dont overlook the obvious!!
     
  18. No Doubt

    No Doubt Seven Time F1 World Champ

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    #18 No Doubt, Mar 20, 2006

    Cool.
     
  19. ernie

    ernie Two Time F1 World Champ
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    #19 ernie, Mar 21, 2006
    So did you replace the plugs with NGK's?
     
  20. PAP 348

    PAP 348 Ten Time F1 World Champ
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    Dec 10, 2005
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    Pap
    #20 PAP 348, Mar 21, 2006
    I hope so :) They are a very good sparkplug :D
     
  21. Juan-Manuel Fantango

    Juan-Manuel Fantango F1 World Champ
    Rossa Subscribed

    Jan 18, 2004
    14,894
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    Juan
    #21 Juan-Manuel Fantango, Mar 21, 2006
    A funny thing happened on the way to the farm-I mean race...One the way to Sebring, my 348 began to run rough, sputter, etc. I stopped by a Central Florida dealer, the cheif drove the car but it did not duplicate what it had been doing. On to Sebring, and it started again. Once I got there, the next day, it was worse. Looked in the yellow pages, and found a bosch certifued mechanic who agreed to look at the car. He pulled it over his pit, cleaned all of the important conections including the flywheel sensor, and it has run fine since! I was ready to have the car trailer 500 plus miles to my trusted mechanic in Charleston SC! The good part is, he is John Dean, holds several SCCA class track records, is the former voice of Sebring, and will instruct me upon my return trip in a few days for the FCA track event at Sebring! How lucky is that.

    Use some electrical connector spray on all of your connections-it may work.
     

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