Spark Plug Wiring | FerrariChat

Spark Plug Wiring

Discussion in '456/550/575' started by dennis_maine, Aug 4, 2019.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
    ME
    Full Name:
    Dennis Haines
    I'm doing some work on my 550, which involved removing the HT leads from the coil packs. I didn't pay attention to where each HT lead went, since they and the coil packs are numbered. Now I find that the numbering of the coil packs makes no sense to me. Cylinders 1 - 6 are arranged, CW from the lower left, in sequence: 1-2-3-4-5-6. Cylinders 7 - 12 are not. They are numbered, again CW from the lower left, 10-12-11-8-7-9. This makes no sense to me. Can anyone shed some light on this?
    Image Unavailable, Please Login
     
  2. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    The arrangement is probably not important as long as the Motronics ECUs fire the spark plug (pairs) at the right time... or are you thinking in terms of wire length? The arrangement seems ok in terms of spark plug pairing, but I'm not sure if it makes any sense in wire length. It depends on where the coil packs are located with respect to each spark plug.

    Regarding spark pairing: The ignition system is a "wasted spark" type. i.e. one coil (primary/secondary) in each 3-coil coilpack is used to fire two spark plugs simultaneously, even though one of those spark plugs will be firing during the exhaust stroke (of the 4-stroke cycle). e.g. the #1 and #6 spark plugs share a coil(i.e. a bottom row spark plug connection has a paired spark plug on the top row (directly above it)

    i.e. 1&6, 2&5, 3&4, 8&11, 7&12, 9&10.

    Looks like this (black lines):

    Image Unavailable, Please Login

    I've shown the firing order in blue lines, but sequence is not so clear. Anyway, the ECUs don't fire the spark plugs 1, 2, 3, 4, 5.... but 1&6, 7&12, 5&2, 11&8, 3&4, 9&10, 6&1, 12&7, 2&5, 8&11, 4&3, 10&9. The last number in a pair is a wasted spark.

    So far, I haven't been able to visualise the effect on the crankshaft with this firing order (it's a little easier on a V8), but you can see the lobes of the crankshaft are arranged in a similar manner to the spark plug pairs (outer pair, mid pair and inner pair).

    Image Unavailable, Please Login

    Maybe if you could slow this video down to 1/4 speed, it might help folks smarter than me figure out the relationship between crank position and firing order:

     
  3. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Dennis, is it possible to see the wire colours on the coil pack plug? Also, is there pin numbering on the plug itself? I'm trying to correct the workshop wiring diagrams.

    Image Unavailable, Please Login

    Thanks!
     
  4. Cribbj

    Cribbj Formula 3

    The same coil can be used for either bank, as long as the cylinder numbering on that decal is observed.

    The confusion over the numbering arises because the LT connector in the harness coming from the ECU is wired differently from the left side to the right side.

    Here's a schematic that should help you:

    Image Unavailable, Please Login
     
    Qavion likes this.
  5. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
    ME
    Full Name:
    Dennis Haines
    OK, cribbj's post answers the question. The LT wires are in a different sequence side to side. I expected that, if cylinders 1 - 6 were connected to the coil pack in sequence, then cylinders 7 - 12 would be too. But, if the LT wires are not in the same sequence, then all bets are off. Why they would do this is anyone's guess. Many thanks to everyone.
     
  6. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,985
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Artifact of two Motronic ECUs, each controlling one bank of 6 cylinders. Just like older V12 Ferraris had one distributor for each bank, with two sets of points in each distributor controlling 3 cylinders. There were exceptions, of course, with some 12 cylinder single distributors.
     
  7. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Excellent tip, thanks John.

    Unfortunately, these workshop wiring diagrams for the engine are still confusing me. Maybe I don't understand the basics. Is the "right bank" on a 550 on the (USA) passenger's side of the car? Does the right bank have cylinders 1~6 like this?

    Image Unavailable, Please Login

    I thought the 550 was like the 355 with the cylinder numbering starting at the front right hand side of the car and ending at the front left hand side (like the diagram above), but then I found a diagram in the manual which shows the 7~12 crank sensor on the passenger's side. See below:

    Engine_sensor_hookup


    And if that wasn't confusing enough, half the sensors feed the opposite side ECUs.

    Thanks!
     
  8. Cribbj

    Cribbj Formula 3

    Ian, yes, your cylinder numbering diagram is correct, and I had the same questions as you when I was researching the purchase of my 550. A lot of the mystery of the "crossed" sensors can be explained by the crossover arrangement of the intake manifold :)
     
  9. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Ah... brilliant... That's one variable I didn't think of.

    I'm working on a summary in case this question should arise again.

    RIGHT ECU:

    Uses:
    Left hand throttle position sensor (now makes sense)
    Left hand side crank sensor for engine rpms, etc. (still doesn't make sense, but there is only one crank anyway).
    Right hand cat O2 sensors and thermocouple
    Right coolant temp sensor
    Right hand cam sensor
    Right hand MAF (now doesn't make sense)
    HVAC "on" signal
    Speedometer signal (from ABS ECU)
    Aircon dehydrator filter pressure switch
    Acceleration sensor (1 off, rhs)


    Controls:
    Left hand side variable intake control solenoid (via left/right bank interconnection plug). Not sure what this does.
    Right hand idle speed controller (don't know if this makes sense yet)
    Exhaust bypass solenoid valve (1 off)
    Secondary air solenoid valve (1 off)
    Right hand canister purge valve
    Right hand ignition coils
    Right hand fuel injectors
    Right fuel pump

    Outputs:
    Tachometer signal to tacho, and other user systems. Derived from the crank sensor on left hand side of engine. Still doesn't make sense.
    Outputs coolant temperature to HVAC system via left/right bank interconnection plug and LEFT hand ECU harness.

    Included in harness:
    Signal to HVAC compressor from HVAC compressor control relay in footwell.


    *************************************************************************************


    LEFT ECU:

    Uses:
    Left hand cat O2 sensors and thermocouple
    Left hand MAF (now doesn't make sense)
    Right hand side Inlet Air Temperature sensor (makes sense, although there is only one anyway for both banks)
    Right hand throttle position sensor (forward plug) (now makes sense)
    Right hand side crank sensor (still doesn't make sense but there is only one crank anyway).
    HVAC on signal
    Speedometer signal (from ABS ECU)
    Aircon dehydrator filter pressure switch

    Controls:
    Left hand canister purge valve
    Left hand ignition coils
    Left hand idle speed controller (don't know if this makes sense yet. Depends on plumbing)
    Left hand fuel injectors
    Left fuel pump

    Included in ECU harness, but not connected to ECU:
    Left hand coolant temperature sensor

    Hopefully I haven't made any mistakes. The pdf (pirated) wiring diagrams didn't help because they labels the diagram showing the right hand ECU as "Left" (and vice versa).

    Thanks again, John!

    Cheers
     
  10. Cribbj

    Cribbj Formula 3

    Ian, I would suggest for terminology clarification, you should use right & left "bank" instead of right & left "hand" as the latter could confuse people who are not familiar with engine jargon.

    I would also clarify that when you're referring to the Left or Right ECU's, your reference point is when you're standing at the rear of the car, so it's the same as when we're referring to a LHD or RHD car.

    I would also double check your MAF and TPS wiring to ensure what you've found is accurate.

    For the confusion with the RPM sensors, we know that the right bank #1 cylinder fires first in the sequence, therefore the right bank RPM sensor has to be mounted where it will "see" the trigger gap on the flywheel, earlier in its rotational sequence than the left bank sensor. This is why it is mounted at, let's say the 6:32 clock position when viewed from the flywheel end, and the left bank RPM sensor is mounted at, let's say 6:28. Keeping in mind that when viewed from the flywheel end, the engine is spinning CCW.

    I also wanted to thank you for all the research and documenting that you're doing. This will be invaluable for people who come after us and will shorten the learning curve immensely.
     
  11. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    All good points, John.

    I used the terms left and right to indicate their position on the car/engine as seen looking from the rear of the car, forward. This is for the purposes of replacing items if the engine management system faults them. e.g. If you have a failure of a crank sensor as sensed by the Left ECU, you don't want to change the crank sensor on the left hand side of the engine.

    The "bank" is signified by the Left/Right ECU assignment in my list. e.g. The Right Motronics ECU (which seems to be in the right footwell) controls the right engine bank (cylinders 1~6). i.e. in relation to fuel injection, ignition, etc. If the Right Bank ECU is not on the right hand side, I have to throw everything out the window and start again :oops:

    I'm hoping there are no differences in RHD and LHD cars in relation to bank assignment and Motronics ECU location. When referring to the relay panel, I will always specify "passenger footwell" to avoid confusion. When working on my RHD F355, I was initially quite surprised to see the footwell relay panel upside down as compared with the manuals, but this is normal on the RHD car.

    The TPS on the right hand side of the car (as shown in the workshop manual and the parts manual) is a dual sensor type with two plugs. On page C2 of the workshop manual, it shows one of the plugs being attached to the Motronics ECU on the left hand side of the car. i.e the one which controls left bank fuel injection and ignition. The other plug appears to feed the Bilstein suspension unit and the steering angle module for reasons I still have to figure out. The TPS location is logical to me because of the crossover manifold.
    Also, on page C2 of the 550 WSM, the MAF sensor on the left hand side of the car is shown to be hooked up to the Left Bank ECU. This doesn't make sense to me as the left hand side MAF is recording airflow to the right bank (because of the crossover manifold). Note that I don't fully understand the inlet manifold arrangement on the 550. What is the function of that centre section with the cavallino on it? Does it have anything to do with airflow?

    Ah.. another gem. Thanks! That explains the setup on the F355 also, but in that case, the left bank sensor is in a central position and the right bank sensor is on the left.

    Cheers!
     
  12. Cribbj

    Cribbj Formula 3

    All the above is correct IMO, Ian.

    With due respect, I would continue to refer to locations as either right or left when you're referencing from the rear of the car, rather than driver or passenger as the latter will actually confuse people if they happen to forget you're working with a RHD car, and they're dealing with a LHD.

    I agree that the MAF signals on page C2 do not seem to follow the "crossover" philosophy, although the TPS signals do, and this is puzzling. The only explanation I can think of, and it's lame, is that the two ECU's dialogue with each other via the CAN bus cable that interconnect them, and maybe this is how the MAF signals coming into one ECU are transferred to the other ECU. Perhaps someone else can shed some light on this?

    In the past we have chalked up certain anomalies in the Ferrari manuals to errors in translation, and just poor technical writers, however I don't think this is the case with page C2, and it would be interesting to be able to understand it better.

    This center section is actually a plenum which allows the left & right side airflows to mix at certain engine RPM's. Inside the plenum are 12 vacuum controlled butterflies which operate according to the graph on page C23 of the WSM.
     
    Qavion likes this.
  13. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Sorry, not sure where I slipped up. I thought I had been particularly careful because I know this site has mostly American viewership. I only say the relay/fuse panel is on the passenger's side because I know this is applicable to both LHD and RHD cars (and it's easier to write "the relay/fuse panel is on the passenger side" than the alternative).

    When you mentioned a CAN bus, I went looking for a fancy shielded, twisted pair of wires :D I don't think Ferrari bothered with the shielding or twisting. The brown-white and brown -green wires can be found in the workshop manual "Alarm" diagram and Left & Right Engine diagrams. i.e. attached to pins 15 and 17 on the 21-pin engine connectors (not far from the ECU and on the same side of the firewall). Somewhere there is a splice which joins up the left and right set of wires. There is also a Left/Right Interconnect connector for the exchange of data, but I don't have a pinout for the Motronics ECU to allow wire identification.

    Interesting...and a very odd shaped graph it is.
     
  14. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Or is the CAN bus the Blue/Yellow/Black wires on pins 84, 85 & 86? I see a typical CAN Bus resistor in that circuit.
     
  15. Cribbj

    Cribbj Formula 3

    Ian, I show CAN signals on the main 88 pin ECU connector on pins 59, 62, 84, 85, 86, and yes, I've seen that resistor as well and wasn't sure if that was a CAN resistor, or a calibration tweaking resistor for the WBO2 sensor.
     
  16. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Strange. I have a red-green wire going to the variable intake solenoid valve on pin 59 on the Right ECU and nothing on pin 59 on the Left ECU. On pin 62, I have a black-yellow wire going to the emergency fan relay solenoid on the Right ECU and no wire on the Left ECU.
    Note that the pdf wiring diagrams not only have the wrong titles for the Left and Right banks, but show faulty pin numbering from pins 10~88 (The numbers are shifted to the right by one pin). Pin 88 is outside the ECU :D

    Here's my first attempt at listing the pins on the Right ECU (with Italian wire colour codes):

    1 (ZN) Right post-cat O2 sensor heat on control
    2 (BV) Idle speed regulator pin 1
    3 (BN) Fuel Injector 1 control
    4 (GR) Fuel Injector 3
    5 (LB) Fuel Injector 2
    6 Earth
    7 Not used
    8 (BR) Check Engine Light
    9 Not used
    10 Not used
    11 Not used
    12 Not used
    13 Not used
    14 (ZB) Right Cat Thermocouple ECU pin C (plug A)
    15 Not used
    16 Not used
    17 (RN) MAF (right hand side) pin 4
    18 Not used
    19 (V) Right pre-cat O2 sensor signal in
    20 (Z) Left hand side (but Right Bank) Crank sensor pin B
    21 (S) Cam Sensor pin 2
    22 Not used
    23 Not used
    24 Not used
    25 Not used
    26 (LR) ECU power (hot battery) Fuse 9
    27 (HG) Right Bank Injector Control Relay (solenoid)
    28 (N) Earth
    29 (BL) Idle Speed Regulator pin 3
    30 (M) Right Pre-Cat O2 sensor heat on control
    31 (LG) Fuel Injector 5 control
    32 (LV) Fuel Injector 6 control
    33 (GN) Fuel Injector 4 control
    34 Earth
    35 Not used
    35 Not used
    36 Not used
    37 Not used
    38 Not used
    39 Not used
    40 Not used
    41 Not used
    42 (ZG) Low fuel signal (for fault diagnosis)
    43 Not used
    44 (HB) Left hand side Throttle Position Sensor (signal?)
    45 (RV) Right hand side MAF (pin 2)
    46 (ZN) RH (post and pre-) Cat O2 signal earth
    47 Not used
    48 Not used
    49 (L) RH Coil Pack pin 3
    50 (R) RH Coil Pack pin 2
    51 (G) RH Coil Pack pin 1
    52 Not used
    53 (SN) Acceleration Sensor (USA only) and right hand side Throttle Position Sensor (power?)
    54 (VG) Right bank Sensor power from relay "O"
    55 (NL) Earth
    56 (G) Right hand coilpack power (from ignition key)
    57 (GL) Relay "U" (Secondary Air Solenoid) solenoid control
    58 Not used
    59 (RG) Manifold Modular Valve (Variable intake)
    60 (SG) OBD2 plug pin 13 and pin 60 of Left Motronics ECU
    61 (HV) Right Bank Anti-Evap Solenoid Valve
    62 (NG) Relay "A" solenoid (Emergency Fan Relay)
    63 (BV) Relay "D" solenoid (Right fuel pump) via relay "L" contacts (Right Fuel Pump)
    64 (HR) Exhaust Manifold Valve solenoid.
    65 Not used
    66 (R) Slow Down Light
    67 Not used
    68 (VN) HVAC compressor "on" signal in.
    69 (CB) HVAC/Dashboard plug pin 8 for ???
    70 Not used
    71 (NB) Acceleration Sensor, left hand Throttle Position Sensor and Right Water Temperature Sensor (power ?)
    72 Not used

    Still working on the Left ECU....
     
  17. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    oops.. my list was truncated...

    73 Not used
    74 (HN) Right Water Temperature Sensor (signal?)
    75 (V) Acceleration Sensor
    76 Not used
    77 (Z) Right Bank post-CAT O2 sensor
    78 (ZN) Right Bank (left hand side) Crank Sensor pin "A"
    79 (B or BG?) pin 79 of Left Motronics ECU and pin 35 of ABS-ASR ECU. Vehicle speed?
    80 (NM) Engine RPM out (to tachometer, etc)
    81 Not used
    82 Not used
    83 Not used
    84 (L) CAN Bus
    85 (N) CAN Bus
    86 (G) CAN Bus
    87 (MV) OBD2 "L" pin 15
    88 (S) Immobiliser Interface Unit

    Here's the Left Bank ECU pinout:

    1) (MN) Left side post-Cat O2 heat on signal
    2) (BV) Idle speed regulator pin 1
    3) (BN) Fuel injector 7 control
    4) (GR) Fuel injector 9 control
    5) (LB) Fuel injector 8 control
    6) (N) Major earth
    7) Not used
    8) Not used
    9) Not used
    10) Not used
    11) Not used
    12) Not used
    13) Not used
    14) (ZB) Left cat thermocouple ECU pin C
    16) (H) Intake Air Temperature Sensor pin 1
    17) (RN) Left hand MAF pin 4
    18) Not used
    19) (V) Pre-cat O2 sensor +ve side
    20) (Z) Right hand side crank sensor pin B (for Left Bank use)
    21) (RB) Right/Left Bank Interconnection pin 8 (RB - 1) (signal from Right Bank crank sensor pin 2)
    22) Not used
    23) Not used
    24) Not used
    25) Not used
    26) (C) Fuse 8 (battery power in). Wire changes colour to "LR" at engine disconnect. This may or may not be an error on the diagrams.
    27) (LR) To pin 8 of engine connector with a colour change to "HG". Then to relay B in footwell (Solenoid control -Left Bank injection)
    28) (N) Earth
    29) (BL) Idle Speed Regulator pin 3
    30) (M) O2 heater "on" signal (Left Bank pre-cat O2 sensor)
    31) (LG) Fuel injector 11 on signal
    32) (LV) Fuel injector 12 on signal
    33) (GN) Fuel injector 10 on signal
    34) (N) Earth
    35) Not used
    36) Not used
    37) Not used
    38) (N) Earth
    39) Not used
    40) Not used
    41) Not used
    42) Not used
    43) Not used
    44) (HB) Right hand side dual plug Throttle Position Sensor (Plug A)
    45) (RV) To pin 2 of Left hand MAF
    46) (ZN) Left bank Cat O2 sensor earth (for both sensors)
    47) Not used
    48) Not used
    49) (L) Coilpack pin 2 (spark plugs 7 & 12)
    50) (R) Coilpack pin 1 (spark plugs 8 & 11)
    51) (G) Coilpack pin 3 (spark plugs 9 & 10)
    52) Not used
    53) (SN) Right hand side Throttle Position Sensor middle pin (plug A)
    54) (C) Via splices to Engine connector pin 13 (engine sensor power - MAF, EMCSV, O2 heaters, etc), i.e. battery power from relay "B".
    55) Earth
    56) (G) Coilpack pin 4 (power to coilpack)
    57) (RL) To Secondary Air Pump control relay via pin 14 of Left Engine Connector
    58) Not used
    59) Not used
    60) (SG) pin 60 of Right Bank ECU & pin 13 of OBD2 plug.
    61) (S) Anti Evaporation Solenoid Valve
    62) Not used
    63) (HG) To Left fuel pump relays via Left Engine Connector pin 6
    64) Not used
    65) Not used
    66) Not used
    67) Not used
    68) Not used
    69) Not used
    70) Not used
    71) (NB) Intake air temp sensor and right hand side Throttle Position Sensor plug "A"
    72) Not used
    73) Not used
    74) Not used
    75) Not used
    76) Not used
    77) (Z) signal power to Left Bank Post-Cat O2 Sensor
    78) (ZN) Right hand side Crank Sensor pin A (for Left Bank)
    79) (BC) Left/Right Interconnect pin via wire BG-1 (pin 9) to pin 79 of Right Bank ECU and pin 12 of Left Bank Engine connector to pin 35 of ABS/ASR ECU.

    Caveat: All data derived from the dodgy pdf wiring diagrams.
     
  18. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    ferraridriver likes this.
  19. crburg4

    crburg4 Rookie
    Silver Subscribed

    Mar 1, 2019
    21
    Springfield, VA
    Full Name:
    Reese
     
  20. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
    Full Name:
    Ian Riddell
    Ahhh.... not sure what happened there...

    Here's the correct link for 550 Lights:

    550 Lights

    My internet provider "iinet.net.au" sometimes posts a picture of a pixelated naked man if I type in the wrong http address. It's supposed to be a reference to their service called "naked ADSL".
     

Share This Page