Mondial 8 -- Tach signal from Engine to Dash | FerrariChat
Buy

Mondial 8 -- Tach signal from Engine to Dash

Discussion in 'Mondial' started by DanielGA, Jul 24, 2025.

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

  1. DanielGA

    DanielGA Karting

    Mar 19, 2018
    198
    Midwest
    Full Name:
    Daniel A.
    #1 DanielGA, Jul 24, 2025
    All,

    I am doing an EFI conversion for my '82 Mondial 8: AEM ECU, coil on plug, EFI, etc.

    Needless to say, the original ECU boxes are removed as well as distributor.

    I am trying to connect things up to the dash.

    Does anyone know where/which wire reaches the tachometer?

    The 9-pin and 15-pin connectors near the former coils drive many things but not the tachometer.

    I have searched around and found mentioning of a "brown with black stripe wire" somewhere, but its totally vague. Did the tach signal leave the Digiplex ECU (so its one of the wires in the Digiplex connector?)
     
  2. Paulmendit

    Paulmendit Rookie

    Feb 26, 2024
    39
    Full Name:
    Paul Coles
    #2 Paulmendit, Jul 25, 2025
    On my QV, there is a brown / black wire that runs from the 11 way connector block on the Digiplex box, disappears into a wiring loom which then runs from the engine bay along the left hand side of the car into the dashboard where it eventually ends up in one the multiplugs behind the clocks before going to the tacho.

    It was pin 10 of the Digiplex and it is only fitted to one of the ECU's - the other is left empty.
     
    Steve Magnusson likes this.
  3. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    574
    NYC
    Full Name:
    Joe
    #3 85QVEuro, Jul 25, 2025
    I think this is what you are looking for...Contact Afterburner here on FC and get his wiring diagrams - you'll save a lot of headaches...Hope this helps

    Image Unavailable, Please Login
     
  4. DanielGA

    DanielGA Karting

    Mar 19, 2018
    198
    Midwest
    Full Name:
    Daniel A.
    #4 DanielGA, Jul 31, 2025
    Super thanks! So Pin 10 from one of the Digiplex connectors. Will find!

    Do you know what type of signal is this? I actually am NOT using the Digiplex but a AEM Infinity ECU. It produces a tach signal (a square wave). Is what the tach expects simple a square wave, one wave per full 4 cycle revolution of the engine?
     
  5. Paulmendit

    Paulmendit Rookie

    Feb 26, 2024
    39
    Full Name:
    Paul Coles
    #5 Paulmendit, Aug 1, 2025
    Can't help with this - beyond my knowledge sphere. There's a website called Dinoplex.org where someone has delved into the family tree of these ECUs - with a lot of info, and if you search 'Digiplex ECU' on here, there's a thread about them - with a link to another thread where there's yet more info.
     
  6. DanielGA

    DanielGA Karting

    Mar 19, 2018
    198
    Midwest
    Full Name:
    Daniel A.
    #6 DanielGA, Sep 26, 2025 at 1:06 PM
    Thanks all! Got it to work! Used Pin 10 as from above diagram --- in my case, both connectors had wires corresponding to pin 10...I choose one of them and it worked. I setup my ACM Infinity ECU to output 2 pulses per rev and now the tach works great!
     
    Paulmendit likes this.

Share This Page