Thermocouple testing | FerrariChat

Thermocouple testing

Discussion in '308/328' started by jonesdds, Dec 11, 2009.

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  1. jonesdds

    jonesdds Formula 3

    Aug 31, 2006
    2,163
    SB,CA & Park City UT
    Full Name:
    Jeff
    I'm curious about the slow down light function in my '89 328. A thread currently active indicates they should light up briefly on startup but mine never have. I had an intermittent flickering prior to the rotor cap going bad but then nothing when the problem became symptomatic. I'm thinking that my thermocouple or ecu might not be working properly. What's a good test for the thermocouple? Can't switch ecus as only one in my car. Thinking propane torch on end of thermocouple is a good test to see if light comes on?
     
  2. PV Dirk

    PV Dirk F1 Veteran

    Jul 26, 2009
    5,401
    Ahwatukee, AZ
    #2 PV Dirk, Dec 12, 2009
    Last edited: Dec 12, 2009
    When the ignition is turned on before starting car the slow down light should be on for a few seconds. I turn the ignition on, wait for the slow down light to go out then start the car. If you are getting no light at all that is a failure, but you knew that. Sorry I don't have anything else. I've been having slow down light issues as well, 87 Mondial 3.2. My car came with a spare used unit. The one originally in car would test properly, after a few minutes of driving around town (not fully warmed up) the light would go straight to solid. When I drove it for 20 miles on the highway at good speed the light would go out for the remainder of the drive. The spare which I just installed tests properly but has a different failure, it flickers all the time. No steady blink, just flickers erratically. I feel like this is more of a bad ground or something but I just don't know. On the flip side I may just have two units that failed in different ways. I was thinking of trying to remove my thermo couple and take a look. I know you didn't ask for my issues, but that is what I'm going through.
     
  3. Futureman

    Futureman Formula 3

    May 16, 2007
    2,024
    Search the board. There's a procedure posted not too long ago on how to put a jumper on two of the leads on the control board in the trunk. I can't remember which ones off hand, but it's documented in a thread somewhere around here.
     

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