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Ferrari 412 /CIS Injection Experts Opinion Needed - Low Power/Weak

Discussion in 'Technical Q&A' started by 360modena2003, Mar 31, 2024.

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  1. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #26 360modena2003, Apr 14, 2024
    Yes, in my case the o-ring was completely flat and there was probably no fuel leaking past the inlet.

    I have removed both inlet mesh filters as well to rule that out.

    Tomorrow I will have my fuel pressure tester and then I can know what is happening.

    BTW, do you happen to know if the metering plate lifts up a lot under WOT?
     
  2. raemin

    raemin Formula 3

    Jan 16, 2007
    2,387
    Lyon (FR)
    Full Name:
    R. Emin
    #27 raemin, Apr 14, 2024
    Never tried to fully lift it, but the distributor plunger slides over a 1,5cm "window", and the disc is actuates this plunger through a long lever, so the disc motion could easily be 10cm. (I moved it and could pass 2 fingers through the aperture)
     
  3. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #28 360modena2003, Apr 15, 2024
    The mystery continues...

    I connected a CIS pressure tester:

    System Pressure: 5 BAR

    Control Pressure: 3 BAR (ambient temp. around 28-30 degrees).
     
  4. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #29 360modena2003, Apr 15, 2024
  5. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #30 360modena2003, Apr 15, 2024
  6. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #31 360modena2003, Apr 15, 2024
  7. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #32 360modena2003, Apr 15, 2024
    These were measured on the drivers side - will measure on the passenger as well, but doubt they will be any difference.
     
  8. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,288
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    Brian Crall
    #33 Rifledriver, Apr 15, 2024
    Ambient temp means very little. What is vital is WUR temp. Was control pressure measured a few seconds after turning key to on for the first time of the day or a few minutes?

    Knowing control pressure cold (a few seconds after first energizing system that day) and fully warmed up is critical and both sides need to be tested in exactly the same way.
     
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,931
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #34 Steve Magnusson, Apr 15, 2024
    Last edited: Apr 15, 2024
    Unfortunately, those don't seem obviously bad. On your 412, it should have a fuel line connecting the "inlet" ports of the two WURs together = so the control pressure should be exactly the same on both banks. Have you tried to measure the actual fuel flow rate from the injectors (volume of fuel delivered/time) for various airflow plate deflections (idle, mid, WOT) -- i.e., "the Dixie Cup test"?

    Example on 400i using quasi-equal size glass jars (but measuring without fuel injectors):
    Image Unavailable, Please Login
    Image Unavailable, Please Login

    Example on TR using 100mL graduated cylinders (measuring with fuel injectors):
    Image Unavailable, Please Login
     
  10. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #35 360modena2003, Apr 15, 2024
    Yes, I this exact test and calibrated each port to flow exactly the same - much better than factory spec :)

    I am flowing exactly 160ccm3 per min at WOT on each injector.
     
  11. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #36 360modena2003, Apr 15, 2024
    I guess I am back to square one - namely timing.

    The flywheels has two PM 1-6, but I doubt I am off by 180 degrees....
     
  12. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #37 360modena2003, Apr 15, 2024
    Control pressure was measured with the engine warm, and with the engine running and off (with the pump running).

    In all cases it was around 3 BAR - System pressure was always 5 BAR.
     
  13. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #38 360modena2003, Apr 15, 2024
    Next would be to measure how much vacuum the engine is "pulling" - does anyone have any values?
     
  14. raemin

    raemin Formula 3

    Jan 16, 2007
    2,387
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    R. Emin
    #39 raemin, Apr 15, 2024
    Given that you cannot crank the engine, vacuum is out of scope for now. Normally your car should start with cold control pressure and zero vacuum, which is when control pressure is at its lowest (i.e max enrichment).
     
  15. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #40 360modena2003, Apr 15, 2024
    My engine starts and runs, it just has very little to no power.
     
  16. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #41 360modena2003, Apr 15, 2024
    The question is by how much does timing have to be off for it to affect vacuum this much?

    Is it possible that the assembly marks were wrong? I will take everything apart again.

    I can have everything off in under 2 hours with an assistant and impact wrench to remove the camshaft sprocket bolts.
     
  17. raemin

    raemin Formula 3

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    #42 raemin, Apr 15, 2024
    Based on the same engine and camshafts The 400i does have 4° less of inlet advance and it is still a strong engine. I would consequently assume that your engine would be significantly out of spec if it feels more tame than a 400i.

    4° at the crankshaft is 2° at the camshaft. So your camshaft would have to be offset by (at the very least) 2°.
     
  18. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #43 360modena2003, Apr 16, 2024
    It is significantly more than just "tame" - it takes around 25 seconds to reach 80 km/h - according to my app that estimates power with acceleration I have around 50 HP...lol
     
  19. raemin

    raemin Formula 3

    Jan 16, 2007
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    #44 raemin, Apr 16, 2024
    What chain tensioner have you used during the rebuild? Mine (from the usual UK supplier) was rapidely stuck, which induced a huge slack. This resulted in a totally out of spec timing.

    With a generous amount of oil, a pry-bar and an hour breaking period, the tensioner was perfectly smooth again, but the initial setting was screwed-up.
     
  20. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #45 360modena2003, Apr 16, 2024
    The tension on the chain is up to spec - very hard.

    I measured it as per the manual.
     
  21. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #46 360modena2003, Apr 18, 2024
    There is something that is confusing me...is it even possible to have good/high compression and low vacuum?

    Will measure compression on all 12 and post the results while I wait on my vacuum gauge.
     
  22. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #47 360modena2003, Apr 18, 2024
    Compression readings from the driver's side :

    Cylinder

    12 - 165 PSI
    11 - 160
    10 - 160
    9 - 160
    8 - 155
    7 - 160
     
  23. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,456
    #48 360modena2003, Apr 18, 2024
    UPDATE: I've discovered the issue, you will never guess what it was!
     
  24. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,931
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #49 Steve Magnusson, Apr 18, 2024
    You're right -- we can't! TELL US WHAT IT WAS!
     
  25. raemin

    raemin Formula 3

    Jan 16, 2007
    2,387
    Lyon (FR)
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    R. Emin
    #50 raemin, Apr 19, 2024
    Rubber boot not seated properly? That would be easy to fix...
     
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