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Spark Plug Erosion

Discussion in '4 Cylinder' started by Model 70, Feb 19, 2012.

  1. Feb 19, 2012 at 5:37 PM
    #1
    Model 70

    Model 70 [OP] Well-Known Member

    Joined:
    Oct 3, 2011
    Member:
    #64548
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    45
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    Male
    First Name:
    Mike
    Central Oklahoma
    Vehicle:
    97 Tacoma 4X4 Pristine Clean
    JRS leaves, Monroe Redi Struts., Later Taco Mini Header, Alpine Tunes.
    I have a '97 Tacoma with 2.7 engine. Mileage is 217,000. Oil changed every 3000 miles.
    I pulled these Split Fire plugs which the PO had installed and replaced them with Denso plugs and new wires.
    Any ideas why plugs 1 and 3 would be so eroded on tips while 2 and 4 were not?

    I performed a compression check on the engine while I had the plugs out with the following results:

    Cold engine:
    #1 175 psi
    #2 160 psi
    #3 150 psi
    #4 190 psi

    Warm engine:
    #1 200 psi
    #2 187 psi
    #3 185 psi
    #4 195 psi

    I am wondering if compression tester that I am using is out of calibration as these numbers seem a little high.

    spark plug 1.jpg
     
  2. Feb 19, 2012 at 5:47 PM
    #2
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

    Joined:
    Dec 18, 2008
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    #11714
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    48,163
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    Ben
    Beech Creek
    Vehicle:
    05 Tundra SR5, 88 SR5 PU, 98 TRD OR (CRUSHED)
    5100's all on fours
    From the FSM:
    Compression pressure:
    1,230 kPa (12.5 kgf /cm2, 178 psi) or more
    Minimum pressure:
    880 kPa (9.0 kgf /cm2, 127 psi)
    Difference between each cyl inder :
    98 kPa (1.0 kgf /cm2, 14 psi) or less
     
  3. Feb 20, 2012 at 5:15 AM
    #3
    Model 70

    Model 70 [OP] Well-Known Member

    Joined:
    Oct 3, 2011
    Member:
    #64548
    Messages:
    45
    Gender:
    Male
    First Name:
    Mike
    Central Oklahoma
    Vehicle:
    97 Tacoma 4X4 Pristine Clean
    JRS leaves, Monroe Redi Struts., Later Taco Mini Header, Alpine Tunes.
    Thank you for the reply on the compression numbers. The other question about the spark plug erosion still bothers me. Could I have a coil pack that is getting weak on cylinders 2 and 4? Or is there a problem with spark on 1 and 3?
     
  4. Feb 20, 2012 at 5:54 AM
    #4
    98tacoma27

    98tacoma27 :POOPCORN: Staff Member

    Joined:
    Dec 18, 2008
    Member:
    #11714
    Messages:
    48,163
    Gender:
    Male
    First Name:
    Ben
    Beech Creek
    Vehicle:
    05 Tundra SR5, 88 SR5 PU, 98 TRD OR (CRUSHED)
    5100's all on fours
    It could just be that they were in the engine too long. The Split fire number cross references with Denso/NGK stock numbers so they should be with in the heat range. The chart below mentions poor fuel economy could cause the electrode erosion. That might suggest the may be the injectors need cleaned/replaced. Perhaps the fuel filter as well.

    [​IMG]
     
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