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    Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

    It's common knowledge that Mitsubishi Motors vehicles manufactured between 1989 and 1994 (and possibly some others) have problems with the Electrolytic Capacitors in their ECM / ECU (Engine Control Module / Engine Control Unit). Here I intend to document my findings with one such example of a common Mitsubishi vehicle that's affected rather heavily by this problem.

    Last December, I bought a Mitsubishi Magna TR. These cars were the second generation of the Magna, produced from 1991 to 1996 as the TR & TS series at Mitsubishi's Tonsley Park Manufacturing Plant in Adelaide, South Australia. They were most commonly sold in Australia, but were exported across the world (including Europe, New Zealand, the Middle East and the United States) under various names and configurations, such as the Diamante, Sigma and V3000.




    In case you were wondering what they look like - Here's one.


    The Magna 2.6L was a common configuration in Australia, and the best way to describe it is essentially a Diamante with the V6 engine removed and a 2.6L 4-cylinder slotted in - the same engine found in the Mitsubishi Starion & Chrysler Conquest, the 4G54 "Astron".

    All in all, they're rather well built cars. The mechanical components are rather robust, the interior trim is resistant to wear, squeaks and rattles and for the most part, electrical components and accessories tend to be trouble-free.

    Be aware that the 1991-1996 Magna also had a luxury version - the Verada KR/KS - which used similar electronics. The engine was different (a 3.0L 6G72 12-valve V6) and as such the control units were different. Unfortunately I don't have capacitor or component specs for these, but I'd imagine they would have similar components and therefore similar issues.
    The Magna drivetrain is controlled by two separate control units, an ECU (Engine Control Unit) that controls the "ECI-Multi 2600" Multi-Point Fuel Injection system, and a TCU (Transaxle Control Unit) that controls the Mitsubishi F4A33 Automatic Transaxle.

    While mechanically these cars are rather decent, failures in the control units or connected components - while simple to correct - are often misdiagnosed as catastrophic mechanical failures. As long as this continues, many of these cars will be written off as uneconomical to repair when in reality they may still have several roadworthy years left. Not brilliant for the uninformed owner, perhaps a little better for electronics hobbyists like us.



    Leaking Electrolytic Capacitors in ECU

    There are many different variants and revisions of the Mitsubishi 2.6L ECU, all manufactured for Mitsubishi Motors by Bosch. From what I can tell, the capacitors tend to be the same. I've examined two ECUs here, and they appear to mostly be the same, differing only by revision.

    - Mitsubishi Part No. AW319647 (Bosch Part No. 9 260 060 023) Year 1992
    - Mitsubishi Part No. AW335189 (Bosch Part No. 9 260 060 046) Year 1993




    A Mitsubishi AW319647 ECU.


    These ECUs contain three capacitors in total, two large Rubycons and a smaller capacitor.

    - (2x) Rubycon 16v 100uF Electrolytic Capacitor, 105C
    - (1x) 50v 22uF Electrolytic Capacitor, 85C

    The problem is that the capacitors over time begin to leak from the base, slowly spreading electrolyte across the PCB and over surrounding components. In severe cases, you may be able to smell a "fishy" smell in the cabin, which is the leaking electrolyte. If left unattended, the electrolyte can short surrounding components or the capacitors themselves can fail, resulting in burned and failed components nearby or exploded electrolytic capacitors that often take surrounding components off the board with them. Ultimately the result is destruction of the ECU and a car that no longer starts.




    Leaking Capacitors and Spilled Electrolyte in a Mitsubishi AW319647 ECU.


    Prior to total failure, the issue can manifest in a number of ways, such as a car that doesn't start consistently, a car that starts fine but idles poorly, a car that cuts out or stalls, or any number of other anomalies. In many cases, the car appears to run perfectly fine, and the only sign of failure is when the ECU releases its magic smoke. The only real sure fire way to know if your caps are leaking is to remove and inspect the ECU.




    The ECU is located inside the dashboard on the left side of the vehicle. Pictured connected is a Mitsubishi AW335189 ECU.



    Leaking Electrolytic Capacitors in TCU

    There are several revisions and variants of the TCU (Transaxle Control Unit) in these cars as well. Some TCUs have two plugs, while others have three. The two are not compatible with each other. It is possible that these variations in the TCU have different capacitors as well, so once again, inspect your TCU first if you plan to do a capacitor job. I only have one TCU handy at the moment, a 2-Plug version.



    A 2-Plug Mitsubishi TCU. Markings: ELC54SMAL1 - MD755123 - G1T13580M - 3920 - Mitsubishi Electric Corp. Japan


    The 2-Plug version appears to have the following capacitors:

    - (1x) 50v 47uF Electrolytic Capacitor, 105C (Dark Blue in Colour)
    - (2x) 25v 47uF Electrolytic Capacitor, 85C (Light Blue in Colour)
    - (2x) 50v 1uF Electrolytic Capacitor, 85C (Yellow in Colour)




    Inside the Mitsubishi MD755123 TCU. Capacitors pictured in upper left of circuit board.


    The failure is largely the same as that of the ECU. Over time the capacitors begin to leak from the base, slowly spreading electrolyte across the PCB and over surrounding components and left unattended, this electrolyte can short surrounding components or the capacitors themselves can fail, resulting in burned and failed components nearby or exploded electrolytic capacitors. The car will still start, however it may be unable to select gears, or will only hold third gear (otherwise known as "Limp Home Mode" or "Limp Mode").

    One common symptom of a failing TCU is that the car will still select gears, but will shift harshly on upshifts or downshifts, resulting in a violent "jerky" motion of the vehicle. This is often misdiagnosed by mechanics as a deteriorating gearbox, and the quotes are often costly - several thousands for the replacement of the automatic transaxle when the issue is a few dollars in capacitors at the most!

    Sometimes the failure of these capacitors can toast the TCU to the point where replacement capacitors will show little to no improvement, so it's best to replace them before a catastrophic failure occurs. If the car is still shifting smoothly, it's still worth having it inspected. Better to catch it now and perform some preventative maintenance than to fork out for a refurbished TCU.



    Changing the capacitors in the ECU and TCU together can save owners many headaches down the track and ensure that the car's electronics continue to operate smoothly. While I've used a Mitsubishi Magna in this example, it affects many Mitsubishi vehicles of the era, and it's not uncommon to hear of this issue on Galants, 3000GTs (GTOs) and anything else with EFI.

    I'm not sure how it looks for other car makes, but if in doubt, it's worth checking over. After all, electrolytic capacitors do have a limited lifespan and the older the car, the more likely it is that they'll be failing.
    Attached Files
    Last edited by iMic; 12-28-2013, 01:08 AM.

    #2
    Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

    There's also a couple of other things worth checking over that certainly apply to Mitsubishi Magna 2.6L EFIs, and possibly some other cars. If you're doing a capacitor job on your car's electronics, it's worth checking the rest of the system as well to make sure you're not leaving other potential trouble spots.

    These are two things I found while looking around under the hood, and while the ECU recap had the car running again, it didn't run smoothly until I attended to these as well.


    Corroded Connectors on Distributor and TPS (Throttle Position Sensor)

    If the car doesn't want to start, or starts and runs poorly, with a rough idle, harshness, vibration or a general lack of power, it pays to take a look at two connectors - the Distributor, which is home to a Hall Effect Sensor, and the TPS (Throttle Position Sensor). These connectors both use rubber boots to seal the electrical connections, but with age, these rubber boots will have hardened, perished and cracked, subjecting the terminals inside to the elements, and they'll almost surely be corroded.



    Location of the TPS and Distributor connections on a 2.6L Magna EFI engine.

    These are rather simple to correct. Using an abrasive such as a sandpaper, you can scrub the green powdery corrosion from the terminals. Use of a Contact Cleaner will also yield good results.

    In the above picture, the connectors are green - these connectors don't normally look like this. Normally they're black and look like, well, connectors. In my case, I've used a green electrical insulation tape wrapped around each connector about 4 times to help seal them up where the rubber boots used to be. The cable ties just help to keep them bundled together.









    Burned Out / Overheated Power Transistor

    The Power Transistor, located under the hood and attached to the side of the Coil, is a critical component in the ignition system. Simply put, without it, the car has no spark. No spark means no start. I haven't seen many of these fail, but it's worth noting this anyway.

    So if your Power Transistor is already burned out, the only option is to replace it. It's toast, done, finished. Mine however wasn't, and many of them out there are still running, and hopefully this bit of preventative maintenance may help keep it that way!




    Location of the Power Transistor and Coil in a Magna TR 2.6L.


    This one's simple. The Power Transistor generates heat, and that heat is shed through the metal plate it's mounted on. Between the Power Transistor and this plate is a thermal grease to help transfer the heat. This grease is around 20 years old by now, and while it may still be perfectly fine, on my car it was dried out.

    I hear that Shin-Etsu thermal grease is recommended (Apple uses the same stuff on their Macs, for the record), but I didn't have any around at the time, so I used Arctic Silver 5 instead. Whether this proves to be sufficient for the task in the long run is yet to be seen, but so far, so good.



    Arctic Silver 5, and in the background, the Power Transistor and its heatsink surface.



    A thin but even layer is best for optimum thermal transfer.
    Attached Files
    Last edited by iMic; 12-28-2013, 01:15 AM.

    Comment


      #3
      Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

      I had the corroded TPS terminals also. It caused intermittent rough idle and mild surging while driving at light throttle.
      Also another non electronic problem that made it very difficult to shift smoothly.
      I found that the throttle plate was wedging in the throttle body whenever I released the accelerator pedal quickly.
      This would cause extra force to be needed to be applied to the accelerator resulting in delayed and abrupt throttle up.
      Adjusting the idle stop screw fixed this.

      Comment


        #4
        Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

        i remember trying to fix a Saab ECM that had thrown an internal ECM fault thinking it was badcaps, but all the caps are polys so its just sitting in my junk bin now
        Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

        "Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

        Excuse me while i do something dangerous


        You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

        Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

        Follow the white rabbit.

        Comment


          #5
          Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

          i still see lots of these.easy fix.the suzuki/geo/chevy tracker has the same issue.

          Comment


            #6
            Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

            I thought I'd show everyone what happens to a Magna TCU when the capacitors leak over time.





            I was planning to replace these capacitors in this unit, but the electrolyte has completely eaten through the traces on the board. That's the worst part about this type of failure. There are no prior symptoms. Once the transmission starts behaving erratically, chances are the board is already damaged. If it reaches the point where the smell of electrical smoke is present in the cabin, that's that. Preventative maintenance is the only way to keep these units alive.

            Thankfully I managed to find two more units locally that haven't leaked yet, so I'll replace the capacitors in these ones before they start to leak.

            With the damaged TCU in, the car would constantly hold third gear. With one of the replacements temporarily in for testing, the automatic now has the full range of gears available again. In addition, the harsh shifting between gears is fixed and the acceleration response has improved dramatically. It's recovered a noticeable amount of power that it hasn't had in some time. It experienced some issues recently where the transmission would hold gears, or jump out of gear entirely - those are fixed too. The engine vibration at idle has also been significantly reduced, and the entire powertrain is much quieter than before.

            Pretty incredible the amount of issues a bad capacitor can cause, and some mechanics would attribute these issues to a costly mechanical failure.




            Also, sending a message out to some of our resident capacitor gurus - see in the photo of the leaking capacitor above? It's positioned very close to a heatsink, which I believe contributed to its failure.

            Would it be possible to run some wire from the board to relocate the capacitor to an area where it wouldn't be as exposed to heat? Or - and excuse the crude phrasing of this question - would the increased distance between the capacitor and board via the wires cause some issues with increased resistance and what not?
            Attached Files
            Last edited by iMic; 02-04-2015, 09:11 AM.

            Comment


              #7
              Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

              Regards; I have a mitsubishi sigma 1992. The box's fault stays in 3rd sometimes. I can not get the location of the tcm / tcu I could indicate where it is thank you very much. Excuse my bad english

              Comment


                #8
                Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                I don't have a Sigma or the factory service manual for it but I suspect the TCU is in the same location as the Diamante/3000GT, on the floor of the center console below and in front of the ECU.

                Make sure to replace the caps in both the TCU and ECU. If they are not bad yet after 20 years they will be soon.
                Attached Files
                Last edited by steve; 03-14-2017, 07:59 AM.

                Comment


                  #9
                  Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                  ready thanks, My tcu is very bad Is it possible to exchange tcu of 3 connectors for one of 2? Someone will have the pinout?

                  Comment


                    #10
                    Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                    Hello All. I'm trying to view the images in this thread but they just show a box with no valid picture and when clicked they just say "Loading ..." but never do. Is this able to be fixed please? Thanks.

                    Comment


                      #11
                      Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                      no, idiots hosted the pictures on a different site - now they are gone.

                      Comment


                        #12
                        Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                        No, as stj says...
                        Sometimes you can be lucky and the page has been archived via archive.org.
                        But also there the pictures are not archived, probably because the image host has disallowed that...

                        You might try contacting the OP via PM and ask if he still has the pictures though.
                        I can fix the links if the originals can be recovered.
                        This is why we try to ask members to please attach the pictures here instead.
                        And when us mods are bored we sometimes attach them to old posts too, however it is extremely tedious and boring work of course...
                        Last edited by Per Hansson; 04-06-2019, 01:52 AM.
                        "The one who says it cannot be done should never interrupt the one who is doing it."

                        Comment


                          #13
                          Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                          Thank you stj & Per Hansson for your replies and suggestions - I'll see what I can do.

                          Comment


                            #14
                            Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                            Originally posted by stj View Post
                            no, idiots hosted the pictures on a different site - now they are gone.
                            "Idiots"? I assembled and submitted this information across a couple of forums, and one didn't support local attachments. The content was directly copied across, hence the externally linked images. It's possible I was either sidetracked or forgot to update them to attachments as time went on.

                            Just wanted to address that.


                            @Flit - Thankfully I have those images archived. They're actually still online as well, the issue is the host domain changed from postimg.org to postimg.cc.

                            Given this thread is now several years old, the original posts appear to be locked from editing, but I'll fix and re-post them as forum attachments here later this afternoon when I'm at home.
                            Last edited by iMic; 04-08-2019, 10:01 PM.

                            Comment


                              #15
                              Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                              Updated Post #1. Images added as attachments. (Click to zoom.)

                              Originally posted by iMic View Post
                              It's common knowledge that Mitsubishi Motors vehicles manufactured between 1989 and 1994 (and possibly some others) have problems with the Electrolytic Capacitors in their ECM / ECU (Engine Control Module / Engine Control Unit). Here I intend to document my findings with one such example of a common Mitsubishi vehicle that's affected rather heavily by this problem.

                              Last December, I bought a Mitsubishi Magna TR. These cars were the second generation of the Magna, produced from 1991 to 1996 as the TR & TS series at Mitsubishi's Tonsley Park Manufacturing Plant in Adelaide, South Australia. They were most commonly sold in Australia, but were exported across the world (including Europe, New Zealand, the Middle East and the United States) under various names and configurations, such as the Diamante, Sigma and V3000.




                              In case you were wondering what they look like - Here's one.


                              The Magna 2.6L was a common configuration in Australia, and the best way to describe it is essentially a Diamante with the V6 engine removed and a 2.6L 4-cylinder slotted in - the same engine found in the Mitsubishi Starion & Chrysler Conquest, the 4G54 "Astron".

                              All in all, they're rather well built cars. The mechanical components are rather robust, the interior trim is resistant to wear, squeaks and rattles and for the most part, electrical components and accessories tend to be trouble-free.



                              The Magna drivetrain is controlled by two separate control units, an ECU (Engine Control Unit) that controls the "ECI-Multi 2600" Multi-Point Fuel Injection system, and a TCU (Transaxle Control Unit) that controls the Mitsubishi F4A33 Automatic Transaxle.

                              While mechanically these cars are rather decent, failures in the control units or connected components - while simple to correct - are often misdiagnosed as catastrophic mechanical failures. As long as this continues, many of these cars will be written off as uneconomical to repair when in reality they may still have several roadworthy years left. Not brilliant for the uninformed owner, perhaps a little better for electronics hobbyists like us.



                              Leaking Electrolytic Capacitors in ECU

                              There are many different variants and revisions of the Mitsubishi 2.6L ECU, all manufactured for Mitsubishi Motors by Bosch. From what I can tell, the capacitors tend to be the same. I've examined two ECUs here, and they appear to mostly be the same, differing only by revision.

                              - Mitsubishi Part No. AW319647 (Bosch Part No. 9 260 060 023) Year 1992
                              - Mitsubishi Part No. AW335189 (Bosch Part No. 9 260 060 046) Year 1993




                              A Mitsubishi AW319647 ECU.


                              These ECUs contain three capacitors in total, two large Rubycons and a smaller capacitor.

                              - (2x) Rubycon 16v 100uF Electrolytic Capacitor, 105C
                              - (1x) 50v 22uF Electrolytic Capacitor, 85C

                              The problem is that the capacitors over time begin to leak from the base, slowly spreading electrolyte across the PCB and over surrounding components. In severe cases, you may be able to smell a "fishy" smell in the cabin, which is the leaking electrolyte. If left unattended, the electrolyte can short surrounding components or the capacitors themselves can fail, resulting in burned and failed components nearby or exploded electrolytic capacitors that often take surrounding components off the board with them. Ultimately the result is destruction of the ECU and a car that no longer starts.




                              Leaking Capacitors and Spilled Electrolyte in a Mitsubishi AW319647 ECU.


                              Prior to total failure, the issue can manifest in a number of ways, such as a car that doesn't start consistently, a car that starts fine but idles poorly, a car that cuts out or stalls, or any number of other anomalies. In many cases, the car appears to run perfectly fine, and the only sign of failure is when the ECU releases its magic smoke. The only real sure fire way to know if your caps are leaking is to remove and inspect the ECU.




                              The ECU is located inside the dashboard on the left side of the vehicle. Pictured connected is a Mitsubishi AW335189 ECU.



                              Leaking Electrolytic Capacitors in TCU

                              There are several revisions and variants of the TCU (Transaxle Control Unit) in these cars as well. Some TCUs have two plugs, while others have three. The two are not compatible with each other. It is possible that these variations in the TCU have different capacitors as well, so once again, inspect your TCU first if you plan to do a capacitor job. I only have one TCU handy at the moment, a 2-Plug version.



                              A 2-Plug Mitsubishi TCU. Markings: ELC54SMAL1 - MD755123 - G1T13580M - 3920 - Mitsubishi Electric Corp. Japan


                              The 2-Plug version appears to have the following capacitors:

                              - (1x) 50v 47uF Electrolytic Capacitor, 105C (Dark Blue in Colour)
                              - (2x) 25v 47uF Electrolytic Capacitor, 85C (Light Blue in Colour)
                              - (2x) 50v 1uF Electrolytic Capacitor, 85C (Yellow in Colour)




                              Inside the Mitsubishi MD755123 TCU. Capacitors pictured in upper left of circuit board.


                              The failure is largely the same as that of the ECU. Over time the capacitors begin to leak from the base, slowly spreading electrolyte across the PCB and over surrounding components and left unattended, this electrolyte can short surrounding components or the capacitors themselves can fail, resulting in burned and failed components nearby or exploded electrolytic capacitors. The car will still start, however it may be unable to select gears, or will only hold third gear (otherwise known as "Limp Home Mode" or "Limp Mode").

                              One common symptom of a failing TCU is that the car will still select gears, but will shift harshly on upshifts or downshifts, resulting in a violent "jerky" motion of the vehicle. This is often misdiagnosed by mechanics as a deteriorating gearbox, and the quotes are often costly - several thousands for the replacement of the automatic transaxle when the issue is a few dollars in capacitors at the most!

                              Sometimes the failure of these capacitors can toast the TCU to the point where replacement capacitors will show little to no improvement, so it's best to replace them before a catastrophic failure occurs. If the car is still shifting smoothly, it's still worth having it inspected. Better to catch it now and perform some preventative maintenance than to fork out for a refurbished TCU.



                              Changing the capacitors in the ECU and TCU together can save owners many headaches down the track and ensure that the car's electronics continue to operate smoothly. While I've used a Mitsubishi Magna in this example, it affects many Mitsubishi vehicles of the era, and it's not uncommon to hear of this issue on Galants, 3000GTs (GTOs) and anything else with EFI.

                              I'm not sure how it looks for other car makes, but if in doubt, it's worth checking over. After all, electrolytic capacitors do have a limited lifespan and the older the car, the more likely it is that they'll be failing.
                              Attached Files
                              Last edited by iMic; 04-09-2019, 03:09 AM.

                              Comment


                                #16
                                Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                                Updated Post #2 and Post #6. Images added as attachments. (Click to zoom.)

                                Originally posted by iMic View Post
                                There's also a couple of other things worth checking over that certainly apply to Mitsubishi Magna 2.6L EFIs, and possibly some other cars. If you're doing a capacitor job on your car's electronics, it's worth checking the rest of the system as well to make sure you're not leaving other potential trouble spots.

                                These are two things I found while looking around under the hood, and while the ECU recap had the car running again, it didn't run smoothly until I attended to these as well.


                                Corroded Connectors on Distributor and TPS (Throttle Position Sensor)

                                If the car doesn't want to start, or starts and runs poorly, with a rough idle, harshness, vibration or a general lack of power, it pays to take a look at two connectors - the Distributor, which is home to a Hall Effect Sensor, and the TPS (Throttle Position Sensor). These connectors both use rubber boots to seal the electrical connections, but with age, these rubber boots will have hardened, perished and cracked, subjecting the terminals inside to the elements, and they'll almost surely be corroded.



                                Location of the TPS and Distributor connections on a 2.6L Magna EFI engine.

                                These are rather simple to correct. Using an abrasive such as a sandpaper, you can scrub the green powdery corrosion from the terminals. Use of a Contact Cleaner will also yield good results.

                                In the above picture, the connectors are green - these connectors don't normally look like this. Normally they're black and look like, well, connectors. In my case, I've used a green electrical insulation tape wrapped around each connector about 4 times to help seal them up where the rubber boots used to be. The cable ties just help to keep them bundled together.









                                Burned Out / Overheated Power Transistor

                                The Power Transistor, located under the hood and attached to the side of the Coil, is a critical component in the ignition system. Simply put, without it, the car has no spark. No spark means no start. I haven't seen many of these fail, but it's worth noting this anyway.

                                So if your Power Transistor is already burned out, the only option is to replace it. It's toast, done, finished. Mine however wasn't, and many of them out there are still running, and hopefully this bit of preventative maintenance may help keep it that way!




                                Location of the Power Transistor and Coil in a Magna TR 2.6L.


                                This one's simple. The Power Transistor generates heat, and that heat is shed through the metal plate it's mounted on. Between the Power Transistor and this plate is a thermal grease to help transfer the heat. This grease is around 20 years old by now, and while it may still be perfectly fine, on my car it was dried out.

                                All I had around was some Arctic Silver 5, intended for computer use. You could easily find something more suitable for this application - and much cheaper, perhaps only a few dollars - at an electronics store like Jaycar.



                                Arctic Silver 5, and in the background, the Power Transistor and its heatsink surface.



                                A thin but even layer is best for optimum thermal transfer.

                                Originally posted by iMic View Post
                                I thought I'd show everyone what happens to a Magna TCU when the capacitors leak over time.





                                I was planning to replace these capacitors in this unit, but the electrolyte has completely eaten through the traces on the board. That's the worst part about this type of failure. There are no prior symptoms. Once the transmission starts behaving erratically, chances are the board is already damaged. If it reaches the point where the smell of electrical smoke is present in the cabin, that's that. Preventative maintenance is the only way to keep these units alive.

                                Thankfully I managed to find two more units locally that haven't leaked yet, so I'll replace the capacitors in these ones before they start to leak.

                                With the damaged TCU in, the car would constantly hold third gear. With one of the replacements temporarily in for testing, the automatic now has the full range of gears available again. In addition, the harsh shifting between gears is fixed and the acceleration response has improved dramatically. It's recovered a noticeable amount of power that it hasn't had in some time. It experienced some issues recently where the transmission would hold gears, or jump out of gear entirely - those are fixed too. The engine vibration at idle has also been significantly reduced, and the entire powertrain is much quieter than before.

                                Pretty incredible the amount of issues a bad capacitor can cause, and some mechanics would attribute these issues to a costly mechanical failure.




                                Also, sending a message out to some of our resident capacitor gurus - see in the photo of the leaking capacitor above? It's positioned very close to a heatsink, which I believe contributed to its failure.

                                Would it be possible to run some wire from the board to relocate the capacitor to an area where it wouldn't be as exposed to heat? Or - and excuse the crude phrasing of this question - would the increased distance between the capacitor and board via the wires cause some issues with increased resistance and what not?
                                Attached Files
                                Last edited by iMic; 04-09-2019, 03:11 AM.

                                Comment


                                  #17
                                  Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                                  Expressing my sincere thanks to iMic for re-posting these messages with the missing pictures included, especially so quickly and efficiently at short notice & fuss-free.

                                  Fantastic !!

                                  Comment


                                    #18
                                    Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                                    Yes, opening the images in a new tab and just changing the .org to .cc in the address bar works fine.

                                    Originally posted by iMic View Post
                                    @Flit - Thankfully I have those images archived. They're actually still online as well, the issue is the host domain changed from postimg.org to postimg.cc.

                                    Comment


                                      #19
                                      Re: Mitsubishi Magna TR/TS / Verada KR/KS Engine & Transmission Controllers

                                      Originally posted by iMic View Post
                                      @Flit - Thankfully I have those images archived. They're actually still online as well, the issue is the host domain changed from postimg.cc to postimg.cc.

                                      Given this thread is now several years old, the original posts appear to be locked from editing, but I'll fix and re-post them as forum attachments here later this afternoon when I'm at home.
                                      Thank you very much for uploading the pictures!
                                      And also for the information about the new url for postimg:
                                      I have put in a replacement variable that changes all old .org url's into .cc so the old links should work throughout the forum now
                                      "The one who says it cannot be done should never interrupt the one who is doing it."

                                      Comment

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