Electrical wonders? | FerrariChat

Electrical wonders?

Discussion in '456/550/575' started by Davidspop, Aug 1, 2020.

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  1. Davidspop

    Davidspop Formula Junior

    Dec 23, 2019
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    Lance Malcolm
    #1 Davidspop, Aug 1, 2020
    So here is an interesting curiosity....this is a momentary switch...its in the footwell cover with the Motronic 2.7 brain...it is disconnected but clearly plugs into the pigtail going onto the ECU.... any ideas?
    View attachment 3127583
     
  2. Qavion

    Qavion F1 World Champ
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    #2 Qavion, Aug 1, 2020
    Last edited: Aug 1, 2020
    Can't see the attachment, but I assume it's the test button. Not sure about the 456, but on the early 355s, this test button will generate a pulsed CEL light which correspond to respective engine bank faults in the ECU memory.

    USA car?
     
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  3. Qavion

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    #3 Qavion, Aug 1, 2020
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  4. Davidspop

    Davidspop Formula Junior

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    #4 Davidspop, Aug 2, 2020
    Thank you again Qavion! You have a deep knowledge of the Ferrari!

    Yes this is a U.S. car. Interestingly I thought the yellow cable would be the diagnostic plug....this one seem to be just unplugged but the wire colors match up.
     
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  5. tazandjan

    tazandjan Three Time F1 World Champ
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    #5 tazandjan, Aug 2, 2020
    2.7 did not have provisions for OBD II, so Ferrari went to 5.2 and was late getting the 456 ready for the required 1 January 1996 OBD II date. Hence no MY 1996 456 GTs or GTAs. F355s were their bread and butter, so they got 5.2 and OBD II done on time with that one.
     
  6. Qavion

    Qavion F1 World Champ
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    #6 Qavion, Aug 2, 2020
    Not quite, Taz. The early F355's have 2.7 Motronics with a pushbutton test. i.e. 95~96 (USA) models. The test procedure above is from the F355 Workshop Manual.
     
  7. Davidspop

    Davidspop Formula Junior

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    Lance Malcolm
    #7 Davidspop, Aug 2, 2020
    It's definitely a pushbutton momentary switch.. only two wires go to it...and it appears to want to plug into a weatherpack plug coming out of the ECU.... with the same color wires on both sides of the plug. I have not plugged it in to try it yet..... moved to other niggles to fix.....

    I bought the WSM for the 1995...... and now I am searching out two challenges.... the speedometer stopped working.... I think that is the speed sensor....and the a/c evaporator housing is leaking into the interior...it's not a plugged drain (already checked) it seems to be coming from somewhere on the right side of the housing around the back corner. (right side sitting in car...so passenger side in U.S.). I cannot seem to find a diagram of how the evaporator housing is put together I found one leak around what I would call the thermistor probe..... but there is another I need to get to and fix.
     
  8. tazandjan

    tazandjan Three Time F1 World Champ
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    #8 tazandjan, Aug 2, 2020
    Ian- Yup, I knew that. I was talking about OBD II and 5.2. All the F355s produced for the US after 1 January 1996 had OBD II and 5.2 DMEs. It took several months for the 456s to catch up.
     
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  9. Qavion

    Qavion F1 World Champ
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    #9 Qavion, Aug 3, 2020
    Interesting. If you lost a speed sensor, I would expect quite a few warning lights and some odd behaviour from other systems. Have you looked at your '95 WSM? Isn't there a speed input to engine management, steering, suspension, etc. Does the manual include wiring diagrams? Ferraris of this era usually send the speed signal to the speedometer and that processes the signals (sometimes dividing the frequency in half) and then sending it to other systems. Does your steering feel heavy at all speeds?

    (EDIT: nevermind, I've just seen your other post. It seems like it is affecting other systems). :D
     

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