Jdizz07

280Z Running Rich - Fouling Plugs - HELP!!

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    Hi All, 

    After getting my 280Z running after a fresh rebuild, I have fixed the smokey burnt oil from a valve seat , however it is still running ultra rich. To the point where after a new set of spark plugs it sounds great, then after 3 minutes of running they look like the photo below. 

    What are some of the ways I can Lean out the mixture to get her running spot on???

    Hopefully the video link below will give you guys an idea of the engine condition etc. 

    Any help would be greatly appreciated. Thanks in advance!

    JD

     

     

     

    Spark Plug.jpeg

    Spark Plug 1.jpeg

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    I agree with Philip,  the coolant temp connector and thermotime connector are the same and likely plugged into the wrong sensor. 

    Just reverse them and see if the rich condition is corrected.

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    Sounds great. 

    Even if you find that the connections are right, measure resistance at the ECU connector to confirm proper function.  Compare the values to the temperature chart in the FSM, or CO's chart which is on the site somewhere.  And clean all of the connections in the harness.  There are two bullet connectors along the fuel rail that could be corroded.

    Another fairly common, difficult to diagnose, problem is a hole in the FPR diaphragm.  remove the vacuum line to the FPR and see if it has raw fuel in it.  It should be dry.

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    btw you do not need to buy new plugs, just clean those with carb cleaner and re-install.  If they re-carbon, continue cleaning and trying to resolve the problem.

    Once you get the over-fuel sorted, the plugs will clean themselves.

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    One more thing - make sure that somebody didn't install turbo injectors or some other high flow injector.  You never know.

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    What is that God awful sound coming from the engine? Sounds like something coming in contact with the fan blade or an improperly fitting distributor rotor? Doesn't anyone else here this?

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    Sounded like normal valve lash noise on my computer.

    Wouldn't hurt to confirm valve lash since the head had been worked on.  Maybe they're loose.

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    I've never heard a valve lash noise that loud before. Maybe my computer speakers are sensitive?  

    Edited by rcb280z

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    Could be the recording device.  Might be your speakers.  I have a Boston Acoustic system with tweeters and separate bass with its own amp.  Circa 1995 Gateway.  Very nice sound.

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    2 hours ago, rcb280z said:

    What is that God awful sound coming from the engine? Sounds like something coming in contact with the fan blade or an improperly fitting distributor rotor? Doesn't anyone else here this?

    Motorhead? LOL

    RIP Lemmy.

    Edited by siteunseen
    • Like 1

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    It's really hard to evaluate using a recorded media like that, but I don't like the sound of it either. The frequency is too high. I can deal with a "tap" at idle, but it's almost a "buzz". I'm thinking alternator bearings or brushes?

    Or, it could just be impossible to tell from a recording like that.  :)

    220px-Lemmy-02.jpg

    • Like 1

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    I get a distinct sense of rocker arms tapping on cam lobes... who knows.

    Here's a sound for comparison - 

     

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    I have a Bose system, bass speaker with 2 surround speakers. Sound is wonderful.

    I'm curious, have you reversed the two connectors mentioned above yet?

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    Thanks for the replies everyone.

    Haven’t had a chance to get to the old girl this week as it’s out at my lockup (problem in London having no garage!), will have a tinker this weekend on all the above possibilities and get back to you. Really appreciate the help and will be in touch over the weekend. 

    JD

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    When you get this problem solved, replace the Champion plugs with NGK's. You will notice the difference.

    Edited by EuroDat

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