328 still running like a bag of nails when cold under 2,500 RPM | FerrariChat

328 still running like a bag of nails when cold under 2,500 RPM

Discussion in '308/328' started by piccolino, May 6, 2019.

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  1. piccolino

    piccolino Rookie

    Jun 5, 2018
    9
    Norfolk England
    Full Name:
    piccolino
    HI thanks for your input on the first thread. i have changed the warm up reg and it is the same.it sounds like it idles on 4 cylinders and at 500 rpm, when the revs are taken up to 2,500 it runs fine, let the throttle off it runs like a bag of nails. as soon as the water temp reaches approx 120 degrees it's perfect. I have found the rear distributor cap with a little piece missing out of it and also very badly condensed.i have changed the cap and 2x new seals.still the same. i have a spare complete coil pack wich i have swapped over with both coils. still the same. next TDC sensor replacement.any other ideas guys? thanks alf
     
  2. EXCELSE

    EXCELSE Karting

    Nov 27, 2014
    105
    Belgium
    Full Name:
    Scuderia Brughia
    Have you checked your vacuum lines?
     
  3. piccolino

    piccolino Rookie

    Jun 5, 2018
    9
    Norfolk England
    Full Name:
    piccolino
  4. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    379
    Morning Piccolino,
    I once had that problem with my 328, and it was one of the ignition modules. Since it has two ignition modules (one on top of each coil), you can unplug one at each time, when checking ( the engine won't stop, it will slow down and run rough).
    Just an easy thing to diagnose.

    Hope this helps!

    John
     
    308 milano likes this.
  5. Hinecker

    Hinecker Formula Junior

    Mar 14, 2011
    379
    Piccolino,
    In case it's the ignition module( Magneti Marelli BKL3B), the module isn't specific for Ferrari, many car manufacturers used them, like Fiat, Alfa, Ford.
    Also to mention, although the module in mounted on the coil bracket, you can replace the module and use the same coil...coils don't fail very often.

    Hope this helps and saves money.

    John.
     
  6. derekw

    derekw Formula 3
    Silver Subscribed

    Sep 7, 2010
    1,520
    London, UK
    Full Name:
    Derek W
    Sorry if this has already been mentioned in another thread, but if your exhaust tubes are exposed, Start it when cold, lick your finger and touch the exhaust tubes to see if some are cold, some hot. IR thermometer works better but I a quick touch with a wet finger works to see which cylinders are firing. Also, have you tried plugging a plug wire onto a spare plug (resting on something metal where it can't fall off) and start it cold to see if there is a healthy spark and that the engine is running a bit slower. Have you checked fuel pressure (hot and cold?) Perhaps a compression test-- valve may be sticking when cold? Can you borrow an O2 sensor/meter to check the fuel/air at different engine temps? Just thinking out loud
     
  7. radlu

    radlu Formula Junior

    Jun 6, 2005
    407
    Check the fuel pump relay.
     
  8. piccolino

    piccolino Rookie

    Jun 5, 2018
    9
    Norfolk England
    Full Name:
    piccolino
  9. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,322
    Tallahassee, FL
    A problem with the relay would cause the car to not run.
     
  10. EXCELSE

    EXCELSE Karting

    Nov 27, 2014
    105
    Belgium
    Full Name:
    Scuderia Brughia
    Does airflow sensorplate move freely? Might be sticky or badly centered.
     
  11. ginoBBi512

    ginoBBi512 F1 Rookie
    Rossa Subscribed Silver Subscribed

    Oct 9, 2016
    3,434
    SO CAL
    Full Name:
    GINO RUGGIERO
    Maybe it could be the ceramic spark plug connectors , just a thought
     
  12. andyww

    andyww F1 Rookie

    Feb 7, 2011
    2,775
    London
    I am wondering if this is similar to mine. When cold it runs at about 800 RPM and makes a "bag of nails" sound which appears to be coming from the exhaust rather than generally from the engine area. Shoving pieces of cloth up the exhaust dulls the sound.

    If the throttle during this time is increased slightly to 1200 the sound goes away. It only lasts for a minute or so before everything warms up then idle at 1000 and totally quiet.
    I had assumed this might be a characteristic of the exhaust when running rich which would be the case when cold.

    I have an inkling this only started to happen after changing all the injectors for new ones. After that the engine was running very rich all the time so I had to lower the mixture adjustment which I did at a test station so I know its spot on when hot, but its very likely to be richer at idle than it was before and I suspected this might be causing some kind of detonation audible through the exhaust.
     
  13. EXCELSE

    EXCELSE Karting

    Nov 27, 2014
    105
    Belgium
    Full Name:
    Scuderia Brughia
    On euro cars exhausts can make a sort of grinding noise when cold, but it goes away when warming up. However the idle should be even and sweet. Even pulses when you hold your hand behind the exhaust.
     

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