550 Marranello runs rich bank 1 | FerrariChat

550 Marranello runs rich bank 1

Discussion in '456/550/575' started by Charlie van Loon, Aug 24, 2019.

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  1. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    I am working on a 2000 550 Maranello that is running rich on Bank 1 and is activating SLOW DOWN . Spark plugs on Bank 2 are Good but on Bank 1 they are Black and fouling out. Global OBDII says Coolant Temp is
    -40 degrees. Trying to check the resistance on Coolant temp sensor for Bank 1 ( there are 2 temp sensors under the intake) . Where can I get a reading on ECU for Bank 1 (what pin(s) and what reading should I see
    (voltage and/or ohms) ???
     
  2. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
    11,484
    Sydney
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    Ian Riddell
    Here is the diagram for the right bank.

    Ferrari 550 Right Bank (1~6) Wiring Diagram

    I'm not overly familiar with the 550, but I'm assuming the power wire is the NB wire (black-white), which goes to 3 different components (from ECU pin 71). The sensor output wire goes to ECU pin 74.

    It's one of the sensors which is vertically oriented. P/N 125769

    https://www.ricambiamerica.com/car-diagrams/ferrari/v12/gt-group-2-seat/550-maranello/water-pump.html

    I'm guessing these temperature sensors are not easy to get to, but if you can, with the ignition ON, you could look for voltage on one of the 2 pins on the connector which plugs into the sensor. Sensors are usually either 12volts dc or 5volts dc. I'd assume it was ok if there were no other faults. Then check the resistance across the two pins of the sensor. If your OBDII reader is showing -40C, I'm guessing the resistance will be high compared to the other sensor (I believe these sensors have a negative temperature coefficient. High temp = low resistance). "-40C" might even suggest an open circuit. Check that the pins are clean and the plug is connected properly.

    Unfortunately, the left bank temperature sensor wiring doesn't go to the Left ECU, so if you are comparing resistances you won't be able to use the same pins on the ECUs. If you can't check resistance at the sensors, you might be able to check the resistance of the right sensor at the ECU and the resistance of the left sensor at the 24 pin Left Engine Dashsboard/Engine Disconnect plug (not far from the ECU). Pins 16 and 18.

    Here's the diagram for the Left side:

    Ferrari 550 Left Bank Wiring Diagram.

    The HVAC ECU seems to provide power for this sensor. Unfortunately, most of the HVAC wiring is unknown.


    As always, I stand to be corrected :D

    Let us know if you have any difficulties.

    Cheers
     
    F456M likes this.
  3. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    #3 Qavion, Aug 24, 2019
    Last edited: Aug 24, 2019
    Just an afterthought. Since there is only one coolant temperature sensor feeding the ECUs, I assume the Right tells the Left what the temperature is. This wouldn't explain why you have a problem on only one bank. I'm concerned that your OBDII reader is incompatible.

    Here's an example of a false reading on a temperature sensor:

    https://www.ferrarichat.com/forum/threads/cel-and-inlet-air-temperature-40-degrees-f.343714/#post-140947026

    If it is a false reading, you might have to go back to basic engine faultfinding for rich running.
     
  4. Cribbj

    Cribbj Formula 3

    Charlie, in addition to Ian's advice, I'd be looking for ignition & injection issues, ie several cylinders misfiring on Bank 1. You can check for ignition misfires by using an inductive timing light on each HT cable on that bank, and see if it's pulsing regularly. You can check for injector misfiring by using a device we call a 'noid here in the US.
     
  5. 12659

    12659 Formula Junior

    Oct 6, 2005
    346
    Seattle WA. USA
    Full Name:
    mark
    check for a vacuum leak, smoke test works best.
     
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  6. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    I went into work today after staring at the wiring diagram I have access to and found that the right side ECU is for Bank 1 cyls 1-6 and only the RH(pass side) coolant sensor reports to ONLY the RH Bank 1 ECU and it was 1571 ohms. The LH ECU(Drivers side, USA Mate) is for Bank 2 and only has the IAT (Air temp sensor) that report to that ECU and it was 1600 ohms .This is good because the vehicle had not been started. Next I checked the powers and ground at both ECUs as well as the fuses (beforehand) and all were present and good . Then I started the engine and read the Injector Pulse milliseconds and found Bank 1 twice as high as Bank 2 (Bank 1 is fouling out the spark plugs). I forgot to mention that I did a visual inspection when the engine was cold , looking over the harness especially the connector and stumbled onto the FUEL INJECTION GROUNDS that the bolts were tight but the grounds on both valve covers were LOOSE(bolts were TOO LONG). I replaced the bolts with shorter ones and added star washers. I fear that I am too late and that there may be a damaged ECU. I went back to BOSCH Basics and disconnected the TPS sensors in case the throttle cables are miss adjusted but it did not help change the Injector Pulse width. We have an ECU rebuilder near us (South Florida) who does ECU diagnostics/repair(he has helped us before with IMMO bypasses on 911 Porsches) and we are going to contact him on Monday.

    Thanks for your help.
     
  7. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    I went into work today after staring at the wiring diagram I have access to and found that the right side ECU is for Bank 1 cyls 1-6 and only the RH(pass side) coolant sensor reports to ONLY the RH Bank 1 ECU and it was 1571 ohms. The LH ECU(Drivers side, USA Mate) is for Bank 2 and only has the IAT (Air temp sensor) that report to that ECU and it was 1600 ohms .This is good because the vehicle had not been started. Next I checked the powers and ground at both ECUs as well as the fuses (beforehand) and all were present and good . Then I started the engine and read the Injector Pulse milliseconds and found Bank 1 twice as high as Bank 2 (Bank 1 is fouling out the spark plugs). I forgot to mention that I did a visual inspection when the engine was cold , looking over the harness especially the connector and stumbled onto the FUEL INJECTION GROUNDS that the bolts were tight but the grounds on both valve covers were LOOSE(bolts were TOO LONG). I replaced the bolts with shorter ones and added star washers. I fear that I am too late and that there may be a damaged ECU. I went back to BOSCH Basics and disconnected the TPS sensors in case the throttle cables are miss adjusted but it did not help change the Injector Pulse width. We have an ECU rebuilder near us (South Florida) who does ECU diagnostics/repair(he has helped us before with IMMO bypasses on 911 Porsches) and we are going to contact him on Monday.

    Thanks for your help.
     
  8. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Ian Riddell
    It's interesting to see that the coolant temp sensor and the IAT have a similar resistance. I would have thought it would have operated on a different principle as different mediums are being measured. Is this just co-incidence?

    You didn't see the links to the coloured, labelled wiring diagrams I provided in post #2? You could have saved yourself some "staring".

    Good find. I just started an annual service on my car and am undoing the "handiwork" of the independent "expert" who did my last major service. Loose oil pipe clips, missing screws, unsecured brackets, electrical cable touching the exhaust, etc.

    Not sure I understand the concept. In relation to the TPS, the manual just says "Standard Operation: The ECU recognizes only 2 positions (idling and fully open)."
     
  9. F456M

    F456M F1 Rookie

    Jan 8, 2010
    3,665
    Oslo
    Full Name:
    Erik
    Did you replace the water temp sensors? They don’t live forever.
     
  10. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    Yes both were replaced and as reported I can read the RH sensor at the RH ECU (Cyl 1/6) and it was 1571 ohms. The IAT sensor read at the LH ECU (cyl 7/12) reads 1600 ohms . Both when engine was cold. But scanner still read -40 degrees. ECUs are at ECU Doctors now being tested. As reported earlier I did find BOTH ECU grounds loose(extremely loose) on the valve covers. The bolts were bottomed out but the ground eyelets were not tight
     
  11. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    Yes both were replaced and as reported I can read the RH sensor at the RH ECU (Cyl 1/6) and it was 1571 ohms. The IAT sensor read at the LH ECU (cyl 7/12) reads 1600 ohms . Both when engine was cold. But scanner still read -40 degrees. ECUs are at ECU Doctors now being tested. As reported earlier I did find BOTH ECU grounds loose(extremely loose) on the valve covers. The bolts were bottomed out but the ground eyelets were not tight
     
  12. niftyfivefifty

    niftyfivefifty Formula Junior
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    Mar 5, 2007
    366
    PacNW
    I am curious to hear your verdict from ECU Doctors. They currently have my ECUs as my right Motronic 5.2 failed, slowly at first, and then completely a couple weeks ago. All of my grounds are secure, but it was also running rich and throwing a comms code. Best of luck.
     
  13. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    Yeah we are closed for the Holiday and the Hurricane Dorian. Nobody knows where it will land and this is going to delay getting our Ecu's back .
     
  14. Charlie van Loon

    Jun 17, 2019
    8
    Vero Beach, FL, United States
    Full Name:
    Charlie van Loon
    And the fueling was rich enough on Bank1 to overheat the Catalytic converter and put the "SLOW DOWN" warning light on
     
  15. niftyfivefifty

    niftyfivefifty Formula Junior
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    Mar 5, 2007
    366
    PacNW
    Cheryl was telling me about how your team was securing the shop for the storm. Best of luck and I hope everyone stays safe.
     
  16. niftyfivefifty

    niftyfivefifty Formula Junior
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    Mar 5, 2007
    366
    PacNW
    I goofed and totally misread your post. Yeah they told me they might be closed next week depending on the damage.
     
  17. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Ian Riddell
    As a comparison, I just tested a new Bosch sensor at 66F (19C) off the car and it gave a reading of 2400 ohms. At 92F (33.3C), the resistance was 1550 ohms.
     
  18. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
    ME
    Full Name:
    Dennis Haines
    i don't mean to hijack this thread, but where did those wonderful wiring diagrams come from? Where can I buy a set?
     
  19. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Ian Riddell
    They are a "labour of love" and, as such, not for sale.... So... here's a free (zipped) download :p :

    550_Wiring_Diagrams_v1.zip

    Unfortunately, I can't guarantee their accuracy (both Ferrari and I tend to make mistakes now and then). Some are "in progress" and all diagrams are being constantly updated as I become more familiar with the car, so it's best to download from the same link to time to time. The online source of the original Ferrari diagrams seems to be missing a few systems (HVAC, door interiors, cigar lighter, intrument dimming circuit, etc). Some systems are shared with the Ferrari 456, so clues to 550 wiring hookup are often found in the 456 manuals which also appear online from time to time.

    Enjoy.

    P.S. I usually mark sections of the diagram "TBC" (to be confirmed) when I'm not sure of the wiring hookup.
     
  20. dennis_maine

    dennis_maine Karting

    Sep 11, 2007
    196
    ME
    Full Name:
    Dennis Haines
    Wow. Thank you so much! What a lot of work! I wonder why Ferrari can't produce something half as useful?
     
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