308 warm start trouble *not* accumulator | FerrariChat
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308 warm start trouble *not* accumulator

Discussion in 'Technical Q&A' started by grwiseman, Sep 1, 2008.

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  1. grwiseman

    grwiseman Karting

    Sep 6, 2005
    53
    Virginia Beach
    #1 grwiseman, Sep 1, 2008
    Hey guys, I am going to run this by you all to see if there are any thoughts... 1985 308 GTS, no modification except CATS are removed...

    About 6 months ago, I began having some warm start issues that I thought would be related to the fuel pressure not holding after shutting off the car (vapor lock of some sort). It starts great if the engine is cold but won't re-start for about 3 hours after I turn it off. For all intents, it sure seems like the fuel accumulator or something similar. But, when we checked the pressure in the system, it is fine.

    After starting the car, I often smell what seems to be coolant, especially after I take a sharp turn while the car is warming up. All the belts were replaced two years ago and there are no coolant leaks on the garage floor. I don't get any coolant smell out of the vents with the heater running - it is more of a smell that permeats the interior for the first couple minutes of a drive. This issue may be totally unrelated, but I wanted to add it to the discussion.

    The previous owner had a warm start problem back in 2000 - he adjusted the CO mixture and said that fixed it. Does anyone know the proper CO mixture so I can check that?

    I think that about covers it. Over to the crazy smart folks to shed some light for me.

    Thanks!
     
  2. fastradio

    fastradio F1 Rookie
    BANNED Professional Ferrari Technician

    Apr 26, 2006
    3,664
    New England
    Full Name:
    David Feinberg
    #2 fastradio, Sep 1, 2008
    This sure sounds like the classic hot pressures leakdown problem...When you say the pressures in the system were checked, do you mean when the engine was warm...and then turned off...and pressures were monitored? In other words, the pressures when the engine is cold are very different when the engine is hot. Although system pressure (the fuel pump is not off) may go to zero, control pressure should be about say 3.2 bar for at least 20 minutes...else she'll be a real bear to start.

    Vapor lock is not the issue....Loss of pressure is; after shutdown.

    Loss can occur due to:

    Pump check-valve
    Accumulator
    Fuel Distributor
    Warm-up regulator
    Injectors

    To check to CO and HC, you'll need an exhaust gas analyzer.
    A typical 308QV, pre cat will read:
    <2% CO
    <200 ppm HC

    If you're at or below these numbers, the car should start hot, presuming the hot control pressure, measured after a 20 minute shut-down is over say 3-3.2 bars.

    Hope this helps...
    David
     

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