How to tell if you have a bad or fried ecu

Posted by theslab, Nov 29, 2010
Newbie Forum - Beginner DSM modification questions and discussions. Common, repetitive, and general discussions will get dumped here from other tech forums. Unless you're a Probationary member you shouldn't post threads here.

  1. theslab

    theslab Proven Member

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    gurnee, Illinois
    This i feel will help everyone on this forum. I got tired of everyone givng false info for a bad ecu like "Fix youre mpi relay" LOL. I've never heard of anyone in my life having a bad mpi relay.

    Warning signs for Bad capacitors in ECU:

    1. A rapid clicking or chattering from under the dash. Usually accompanied with
    the engine stalling or losing power during the noise. This is the microcontroller
    going into reset over and over and over again due to a bad power supply. Every
    time it resets, it will turn the fuel pump relay on and off. This could also be
    a bad fuel pump relay, but not usually.

    2. An usual smell that seems to come from the center console. Especially if i
    smells like rotten seafood. Consider that it could also be your heater fan motor,
    unless accompanied with a power loss or stalling.

    3. Your car is older than seven years and sees a lot of extreme temperature
    transitions. If you experience either of the first two problems above, act
    on them as soon as possible. Even though your car may still be drivable, the
    longer you let the problem go the more likely you will end up with a hole
    in your ECU's PC board or with several blown components on the board. Then you will have to dig an ecu up in the junkyard or buy a new one from Mitsubishi
    for $1100.


    Note to interpret dates (9806.1 used as example)
    1st and 2nd (2) digits are year so this is 1998
    3rd and 4th (2) digits are month so this is June (6th month)
    5th digit is 1/3rd of month (I think) so 1 = 1st 10 days of month


    Important information about buying a replacement or repaired ECU:

    You do not have to install the exact same ECU part number in your car BUT you do have to install a new ECU
    with the same E2T number!
    Pull out the ECU and under the part number on the label there will be a number starting with E2T.
    Those numbers on your original ECU have to match your new ECU.

    How to tell if you have eprom http://www.technomotive.com/howto/ecu1g/checkeprom.htm

    Best of Luck :hellyeah:
    Last edited: Nov 30, 2010
    #1
    luv2rallye likes this.
  2. iugrad92turbo

    iugrad92turbo Proven Member

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    Pull it out and look at the caps, you can tell burned ecu look at it and smell it easy to se.
    #2
  3. luv2rallye

    luv2rallye DSM Wiseman

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    Great post/article theslab! I can now link many "Is my ECU bad" questions to it.
    #3
  4. street_flight

    street_flight Probationary Member

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    I suspected that mine was bad when both fans would turn on as soon as the car started and it ran like it had the MAS unplugged. Of course I checked the ECT sensor to the ecu and the MAS connection to the ecu but the ecu was definitely the culprit.
    #4
  5. T-mun

    T-mun Proven Member

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    A new ECU from Mitsubishi is totally out of the question.. A new one From AEM is more like it.. ;-)
    #5
  6. DSM1G90

    DSM1G90 Supporting Member

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    Looks like some of this info was stolen from the motoguys site and then reworded - place that rebuilds ECU's (in which they do great work for their cost for exchange..) and sells them for an affordable price along with a trial period.


    www.motoguys.com
    #6
  7. iugrad92turbo

    iugrad92turbo Proven Member

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    yes you can even look on eBay for rebuilds, ecmlink can do it too, just look for ecu rebuilds.
    #7
  8. donniekak

    donniekak DSM Wiseman

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    I have seen some awful work come out of motoguys, i do not recommend. They do enough to get the board to function, and ship it out.
    #8
  9. DSM1G90

    DSM1G90 Supporting Member

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    I got a Motoguy's ECU in my ride for close to 2 yrs without any problems.

    BUT, if you do any sensor work with the battery connected and short out the connector to the sensor by touching it to ground, it can blow a ground bus in the ECU.
    #9
  10. eburg2490skillz

    eburg2490skillz Proven Member

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    i just got done installing my 16g big turbo on 15psi. drove it fine with no problems for a day. the next day i went to drive my car, but my car wont go over 3500 rpm. acting like a rev limiter. i am hearing a faint click sound under the headunit. idle is a little rough, but doesnt stall out. could this be my ecu in "safe" mode? plugs and wires ok. bov is recirculated and no boost leaks. no unusual smoke and no exhaust leaks. fuel is not cutting either. im stuck on this problem
    #10

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