QV starting response; cold vs warm | FerrariChat
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QV starting response; cold vs warm

Discussion in '308/328' started by DWPC, Jun 27, 2011.

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  1. DWPC

    DWPC Formula Junior

    Mar 10, 2011
    733
    Sedona AZ
    Full Name:
    Dennis
    #1 DWPC, Jun 27, 2011
    I'm still learning "normal" for my '85 308 QV. Cold start (i.e., ambient 60F) is virtually instant and strong; idle drops to a pretty smooth 800 RPM or so and gradually rises over a few seconds to near 2000 RPM for a couple minutes..then to under 1000.

    But when starting after fully warmed up, I have to crank the starter for a few seconds and then it fires up rather anemically; like its only catching on a couple cylinders initially. It reminds me of starting a flooded engine. Its not really hard starting when warm, just not "crisp"; whole sequence is less than 10 seconds.

    My test equipment is limited to a multimeter. I'm assuming its something in the K-Jetronic. Suggestions?
     
  2. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,345
    #2 Paul_308, Jun 27, 2011
    Last edited by a moderator: Sep 7, 2017
    There is a circuit which can malfunction causing the cold start injector to flood the air plenum making the engine difficult if not impossible to start when warm or hot. To prove this, unplug the connector (red arrow below) to the cold start injector which located at the right side of the plenum. The thermoswitch is a component which turns off the cold start injector after a few seconds and often goes bad. There are a few other possibilities but first disconnect the cold start injector and go from there.

    Incidentally, disabling the high rpm idle is a controversial subject but quite doable. Read Birdman's treatise and choose your poison. Or leave it alone. In any case, this read will help you understand the present problem. http://www.birdmanferrari.com/service/cold_start/cold_start.htm Note the cold start injector is #1 on the diagram.

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  3. PV Dirk

    PV Dirk F1 Veteran

    Jul 26, 2009
    5,401
    Ahwatukee, AZ
    #3 PV Dirk, Jun 27, 2011
    The accumulator is designed to hold pressure in the system for a while to avoid vapor lock and ease warm starting. The accumulator is another potential source of your problem, but you'd have to test residual system pressure after shutting down the engine to know for sure. Without test tools it's a guess. Accumulator is down by the fuel pump.
     

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