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F355 Blue Smoke

Discussion in '348/355' started by MartinPO, Mar 28, 2023.

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  1. MartinPO

    MartinPO Rookie

    Aug 28, 2016
    31
    Port Orange FL
    Full Name:
    Martin Clark
    #1 MartinPO, Mar 28, 2023
    An issue with my gated 1997 F355. Symptom was misfire and occasional white smoke from both sides for about 2 minutes on some cold start-ups (no sign of water in oil). Replaced plugs and leads, no change. Replaced fuel filter and ran Techron fuel cleaner, no change. Removed injectors and sent to RC Fuel Injection for cleaning and calibration. Seven cleaned and re-calibrated, one replaced with a Bosch injector from Five-O Fuel Injection (this has not been calibrated). After battery power-up, upon start-up misfire has gone, but continuous blue smoke from both sides, which smells of fuel belches out. I let it idle for 15 minutes to let the ECU's talk, no change and it gets worse at higher RPM, smoke lingers at the tailpipes after shut-off. I do have videos of the blue smoke if needed. Any suggestions would be helpful please?
     
  2. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    #2 Targatime, Mar 28, 2023
    You might want to provide basic info on the car like how many miles on it
     
  3. GrigioGuy

    GrigioGuy Splenda Daddy
    Lifetime Rossa Owner

    Nov 26, 2001
    33,156
    E ' ' '/ F
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    Snike Fingersmith
    #3 GrigioGuy, Mar 28, 2023
    Have the original valve guides ever been replaced?
     
  4. MartinPO

    MartinPO Rookie

    Aug 28, 2016
    31
    Port Orange FL
    Full Name:
    Martin Clark
    #4 MartinPO, Mar 28, 2023
    39k miles, original (not bronze) valve guides to my knowledge. Keep in mind the 'new' fuel tainted smoke did not occur until after I changed injectors, which solved the misfire.
     
  5. jjtjr

    jjtjr Formula Junior

    Aug 29, 2016
    761
    Vermont
    Full Name:
    john truskowski
    #5 jjtjr, Mar 29, 2023
    What is the fuel pressure? Also, was the misfire caused by leaking injectors? If so, the excessive fuel may have washed down the cylinders, and possibly polluted the engine oil too.
     
  6. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,449
    Los Angeles
    #6 Targatime, Mar 29, 2023
    A '97 will have bronze valve guides -- the changeover was in mid-'98 production. This does not mean you have worn valve guides, of course. Just a point of clarification.

    If the exhaust smells of fuel, I would start there. If fuel/ignition was fine, and you were getting oil smoke, then sure, look at rings/guides. But if your exhaust smells of fuel even after the engine is warm, figuring that out is job #1.
     
  7. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,732
    #7 Mitch Alsup, Mar 29, 2023
    Blue smoke means oil is being consumed in the combustion chamber.
    {This is doing nothing good for your CAT either}

    Ways for oil to get into the combustion chamber::
    a) leaks past valve guide and valve stem
    b) leaks past piston rings and cylinder
    c) excessive blow by runs oil up through Helmholtz resonators via dry sump

    Note: when I did the valve guides in my F355 engine, you could move the valves more than 1mm (back and forth) and yet it was not consuming oil nor blowing blue smoke.

    It is time for a leak-down test on this engine. {That is:: If you really want to know what the problem is}
     
    IvanRico and Pangea like this.
  8. cactussed

    cactussed Formula Junior

    Mar 12, 2008
    290
    #8 cactussed, Mar 30, 2023
    Broadly speaking, blue smoke on startup = leaking valve guides / stem seals. Blue smoke on revving it = worn rings / liners.
    Have you changed your oil yet? If you've had ongoing leaking injector, then you've possibly contaminated your oil (effectively thinning it) which will make blow-by more likely and also stink of fuel.

    Start with simple stuff first.
     
  9. bobzdar

    bobzdar F1 Veteran

    Sep 22, 2008
    6,895
    Richmond
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    Pete
    #9 bobzdar, Mar 30, 2023
    Make sure all of the vacuum lines and evac system were connected properly. The dry sump operates the engine internally under vacuum and if that gets messed up, you can get oil where it shouldn't. Given a bunch of that would have to be disconnected to get the fuel enjectors out, I'd check to make sure that's all connected properly, then (as suggested) see if the oil stinks like gas. If both of those aren't the problem, then proceed with compression and leak down checks.
     
  10. MartinPO

    MartinPO Rookie

    Aug 28, 2016
    31
    Port Orange FL
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    Martin Clark
    #10 MartinPO, Apr 7, 2023
    Thank you all for your input, here was the problem: The new fuel injector was not the correct unit, only reading 12 ohms resistance, the original injectors are apparently 16-16.5 ohms. This apparently confused the ECU and caused the injector to stay open, plus played heck with the others. So if buying a new injector get them calibrated to make sure they match. Thanks to RC Fuel Injection for finding the issue after sending the seven, plus the new one back to them.
     
    blox79 likes this.

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