348 - 348 runs badly, smokes and fires | Page 2 | FerrariChat

348 348 runs badly, smokes and fires

Discussion in '348/355' started by Aeroflop, May 1, 2023.

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  1. RJB (holland)

    RJB (holland) Karting

    Apr 7, 2022
    230
    Holland
    Full Name:
    Roel
    How did this end?

    My 348 seems to have the same problem.
     
  2. steved033

    steved033 F1 World Champ
    Owner Silver Subscribed

    Apr 12, 2017
    10,364
    Atlanta, GA
    Full Name:
    Steve D.
    no one said bad plug wires?

    I'd break up pretty bad at low-mid RPM. redid the plug wires and all was good.

    sjd
     
  3. Aeroflop

    Aeroflop Karting

    Mar 1, 2022
    67
    Finland
    Full Name:
    Eero Ahonen
    This hasn't ended yet. I had really hectic and tiring winter and after that quite hectic summer, having less time and energy for cars. That's a long story for not now (maybe for another time), but basically I haven't been in the garage all summer but quite much less.

    Anyway, let's continue this story.

    After identifing the FPR to 3.0bar and ordering the well-known PR161 from Rockauto, the car got a lot better, but still not good. As we got through the ignition system at the beginning I was still determined for the fuel.

    I took the injectors to Finjector to check and service, they are all within 1% in all measured values, so the fault is not there. After that I took the broken FPR with me to Finjector and bought a fuel pressure meter with fitting adapters (this is why I took the FPR with me - to ensure the threads etc on the counter), got home and at first took a reference from the right side by swapping the fuel pump relay with a jump wire. As the engine is not running, the FPR reference pressure is the atmospheric pressure and the fuel pressure should be the FPR spec pressure.

    The right side said 3.8bar and it runs fine. I switched the meter to left side and got the 3.0bar as I should from PR161. As the 3.8bar FPR's are measured in platinum, the next day I drove back to Finjector with the broken FPR and told the trainee on the counter that I need an FPR to replace this one and with 3.8bar pressure. The summer trainee was a bit astounished and couldnt' answer, but realized to ask for help from more experienced person. We built an AEM configurable FPR with sufficient adapters to take care of the fuel pressure. I installed it, configured the fuel pressure to the same as on the right side.

    At this point, the car is running on 8 cylinders and idling nicely, so I reserved an inspection time for the yearly inspection. Driving there, the car starts rumbling at 4000rpm. At the inspection station I negotiated with the inspector to get use of the exhaust analyzer - the HC is still high. It gets down if I remove the left side fuel pump relay. While running there, I disconnected and connected individual injectors etc. Pushing the MAF connector made a huge difference there, so I found one fault from there.

    After getting home, I tightened the left MAF connector. At this point the car is still not perfect but runs well enough to drive a a bit. The next week goes in wedding arrangement and we did have the Ferrari as our wedding car, as planned, but it's still not happy at higher revs.

    After honeymoon I digged myself back into the engine compartment and found 2 suction leaks from left side, one from intake and one from the EVAP system. I also measured and ensured that the left MAF itself works and checked that the intakes are balanced.

    Still not perfect, but much better than at the beginning. Nextly I will change (not just tighten) the contacts on fhe MAF connector as they don't seem to hold on anymore, put in fresh plugs and hopefully have a fully running engine again.


    So, the problem has gone in this way:
    -FPR fails, letting full pressure to injectors and pushing a little extra to plenum also via the suction line
    -Over-pressured fuel with rich plenum air washes the plugs, which end up with losing the spark
    -I notice the missing spark first, turn the ignition side upside down with new parts and extensive measuring
    -After ruling out the spark side, I turn to the fuel and find the failed FPR
    -I manage to identify the FPR wrongly and the a wront FPR
    -After ensuring the correct pressure I get an FPR which give me the correct pressure
    -During this time, maybe after few unplugging/plugging the left MAF connector fails
    -Due to failing MAF connector the engine floods the plugs again and loses sparks
    -As a bonus there has been a couple of suction leaks that are dependant on the position of the lines disturbing the ECM and my measurements throughout all the procedures

    I might have forgotten to mention this, but I've swapped the wires back and forth from left to right vice versa, the problem stays on the left side and the right side continously runs nicely, so I've ruled the plug wires out.

    After this digging, I'd start by checking the fuel pressures and MAF's / MAF connections.
     
    PP70 and Qavion like this.
  4. Ferrarium

    Ferrarium F1 Veteran
    Sponsor Rossa Subscribed

    Jul 28, 2018
    5,728
    Central NJ
    Full Name:
    Eric
    Did this start after a major service?
     
  5. Aeroflop

    Aeroflop Karting

    Mar 1, 2022
    67
    Finland
    Full Name:
    Eero Ahonen
    For me no, there was 2 years after major before this.
     
  6. KevZep

    KevZep Formula Junior

    Feb 17, 2020
    568
    New Zealand
    Full Name:
    Kevin Bennett
    You need to send the injectors away for ultrasonic cleaning, new pintles fitted and flow testing.

    Everything else is all good stuff to be doing, especially the fuel pump situation.
     
    PP70 likes this.
  7. Aeroflop

    Aeroflop Karting

    Mar 1, 2022
    67
    Finland
    Full Name:
    Eero Ahonen
    A conclusion of all that was/went wrong with the car I started this thread with.

    1. My left FPR faulted and started letting all gas that came from the pump to the engine
    2. The fuel flood took the spark plugs with it
    3. The car has been upgraded to Motronic 2.7 and 3,8bar fuel system, at first I got 3,0bar FPR, now running AEM configurable one
    4. I got some internally faulty spark plugs new from the packet (NGK Iridium)
    5. The wiring to the coil packs is swapped comparing to the coil pack definition, therefore 5&8 should be plugged to outputs 2&3 and 6&7 should be plugged to outputs 1&4
    6. There was a leak on one small suction line
    7. The connectors (pins) for left MAF and left ignition driver were loosened

    There was some slight escalation of the fault with the ignition parts. Now all that is fixed and the ground points on the top of the engine has been cleaned and protected also and the car sings nicely again. And I'm somewhat wiser also experiencing these.
     
    Gargamel647, Jatzz, Robbe and 2 others like this.

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