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Re-Introduction (diagnosing/resolving MEMCAL failure)

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  • Re-Introduction (diagnosing/resolving MEMCAL failure)

    Howdy team SyTy.

    I hadn't realized until I was digging for some info that the old .net site appears to be dead. So, I signed up here.

    I own 1993 Typhoon 2129. It's Green/Grey. I have had it since 2011. I haven't driven it much over the last 2 years as there have been projects that took much longer than anticipated. I had the wheels restored locally and that kept it on jack stands for several months. While it was on those stands the battery died, and well it hasn't ran right since. I was prepping it for the RadWood L.A. show last year at the Petersen museum. I barely made it out of my town and something happened. It just starter running like crap, sputtering, misfiring... I have gone through several cycles of troubleshooting, changing almost every sensor and associated items. It'll start up just fine, but after warm-up, back to the same rough, sputtering. It is like the EPROM is dead. I get nothing from the ALDL. TTS Datamaster won't connect, ALDL Droid connection times out, nothing. Upon close inspection of the EPROM there is some what looks like heat discoloration between a couple of pins and looks like corrosion outside of the discoloration. I am now pretty sure the EPROM is physically bad and probably not re-flashable. Where do I get a new EPROM to test this. Like some of the other SyTy unique stuff (Intake Tube, Console lid hinge, etc...) am I S.O.L? Can I start with a custom burn on a generic EPROM? Where do I get one?

    Thanks for any input! I so miss driving this thing and want it back on the road. Driving my 2011 Ram is boring.

  • #2
    FYI, I moved this topic to the tuning forum since it's answer will pertain much more to that forum than general SyTy chat. Having said that.....

    If you're unsure if your MEMCAL (that's the name of the entire "chip") is bad, try to locate a local SyTyer that is willing to let you try their's and see if it resolves your issue. It's possible that your MEMCAL is fine and the ECM itself is faulty. Our's are particularly fragile and susceptible to moisture damage. Borrowing known good components from another truck is the easiest, most proven way to diagnose things outside of your ability. If that's not possible, then there are a few approaches. I'm going to discuss the cheapest two options:

    1) - Buy a MEMCAL from the SyTy community (create a WTB on the FB group is easiest way) (cost = probably $40-50)
    2) - Create your own piggybacked setup with an EEPROM (total cost = $100-$140).

    One of the beauties of going with your own piggyback setup is that it gives you the ability to modify your own tune (with TunerPro, PromGrammer, etc...) and reflash your own EEPROM with ease. While not as easy as emulation, it does give you tuning ability for less cost. For your own piggyback setup, you'll need 4 items:
    • A MEMCAL (doesn't have to be stock, so long as the ESC circuitry (the circuits under the "gooey clear stuff") is uncompromised).
    • An Adapter (Red Devil River, Moates, etc....)
    • An EEPROM (AT29C256 or 27SF512 are your best bets)
    • An EEPROM Burner (Moates BURN2 is easiest way to go)

    I made mention of the necessity of healthy ESC circuitry on the MEMCAL. This is the part of the stock MEMCAL that the piggyback setup uses to make a complete "chip". If that circuitry is compromised (physical damage, moisture, etc...), then you will have issues beyond working around the EPROM itself. Now, with those 4 items, you need to burn your bin file onto the EEPROM (erase it first to make sure it's clean). Now burn your bin file onto the EEPROM using the following offsets:

    AT29C256
    Buffer Start >> End - 000000 -> 003FFF
    Chip Start >> End - 004000 -> 007FFF

    27SF512
    Buffer Start >> End - 000000 -> 003FFF
    Chip Start >> End - 00C000 -> 00FFFF

    With that done, just assemble the adapter and insert it into your ECM. Here's a video by Moates.net showing the assemble process.



    If you decide to go the Moates route, here's some links to get you started:

    G1 Adapter
    27SF512 EEPROM
    GP1 Adapter (includes the G1, a ZIF adapter and two EEPROMS)
    BURN2 EPROM Programmer

    Moates document on offsets
    1580BBZB Stock 1993 Typhoon Bin File
    Hood
    Syclone #1596
    ISTR Treasurer & Underwear Model

    Comment


    • #3
      Thanks for the info. It's a bit to chew on. I do have a spare ECM that acts the same. The only moisture event I can think of that could possibly have caused anything was the heater core leak a few years before things went wonky. The Ty is a desert truck, I keep it in the garage and I don't even use water for washing. Living 2 hours from anyone that would possibly be willing to let me try their MEMCAL or a full up ECM is a hinderance. So, is this what breaks me and pushes me off the ledge into the world of...gasp...facebook…? I like the idea of learning and doing a custom burn, but California and emissions...hmm... First world problems.

      Thanks!

      Comment


      • #4
        Originally posted by green73 View Post
        Thanks for the info. It's a bit to chew on. I do have a spare ECM that acts the same. The only moisture event I can think of that could possibly have caused anything was the heater core leak a few years before things went wonky. The Ty is a desert truck, I keep it in the garage and I don't even use water for washing. Living 2 hours from anyone that would possibly be willing to let me try their MEMCAL or a full up ECM is a hinderance. So, is this what breaks me and pushes me off the ledge into the world of...gasp...facebook…? I like the idea of learning and doing a custom burn, but California and emissions...hmm... First world problems.

        Thanks!
        IMO, emissions testing is all the more reason to do a custom burn. You can load a bin with lean fueling and pass your test, then go home and load your normal bin for the other 729 days (I assume you have biennial inspection). I could list a thousand advantages to doing your own tune, but that's for another thread.

        The spare ECM.....are you reusing your current MEMCAL or does it have a different one installed?
        Hood
        Syclone #1596
        ISTR Treasurer & Underwear Model

        Comment


        • #5
          Using the current MEMCAL. I don't have an extra. Yes this conversation is giving me thought of custom burning now. I never really thought of flopping back and forth. I do appreciate your input for sure.

          So, yep I joined up on the Facebook too. Finally broke down.

          Comment


          • #6
            Well. I had the EPROM checked and reflashed to stock by gmeproms.com He said there was "Experimental Mode with check sum disabled" code on it. It didn't change anything though. It's very weird. I can jumper A-B and get the CEL to flash the code 12. I checked the wiring from the ALDL to the ECM connectors and the grounds. Pin A to ground is good. Pin B to GE12 is good. BA12 to ground is good, and Pin M (serial data) to BA9 is good. I disconnected the Intake Air Temp sensor, and the Throttle Position sensor while it was running (badly) and no Check Engine Light, and no change in how it was running. The CEL does come on with the key on, and it randomly flickers when it's running. Does anyone know if the 440 power signal on pins BC16 and BB1 engages anything in the ECM that could cause this weirdness? They are 12 volt vs. 5 volt at GE12. I haven't volt checked those 2 yet to see if 12 volts is making it to there. I guess that's next.Since the CEL is lightingand the truck does start, I am guessing the BA6 to GE7 ignition switch circuit is good.

            Comment


            • #7
              Circuit 440 is hot at all times. 440 is the ECM B fuse. The ECM uses 440 for DTC memory, and I believe, as the source for the (+) 12 control signal that is sent to the fuel pump relay. All other ECM controlled relays and solenoids are (-) trigger controlled. Only the fuel pump relay is controlled with a battery voltage signal, and it may come from 440.

              Comment


              • #8
                So, I do have 12 Volts on the 440 signal at the BC16 and BB1 pins. I was thinking (incorrectly of course) that I may have blown the fusible link from the ECM-B when changing the battery somehow. But if that happened it wouldn't start at all. Hmm... What to check next....hmmm back into the manual I go... Even though I've replaced the entire ignition system, I think I will look into the Ignition Control circuit check on page 3A-62 in the manual. Still the no hard set trouble code thing is throwing be off.
                Last edited by green73; 11-08-2019, 02:06 PM.

                Comment


                • #9
                  Pull the vacuum hose off the MAP with it idling. It should go black smoke rich, and in less than a minute, set Code 33 signal voltage high (low vacuum). If in closed loop, and the O2 system is responding it may also set Code 45, rich exhaust indicated.

                  There's a couple of checks of the diagnostic system. If you can't get the system to set codes, or link to your scanner Data Master the way it used to, I'd be thinking you have a bad ECM. I've been around these trucks for 25 years and I've never seen a bad ECM other than idle control problems. This is a first. But if it won't retain intentionally set codes, what else could it be?

                  Comment


                  • #10
                    Thanks for the idea forcing the code 33. I'll give that a try in the morning.

                    Comment


                    • #11
                      So, apparently that jump start a long time ago did something to the PCM and the ECM. In troubleshooting, I put the MEMCAL in the spare ECM and the problem followed the MEMCAL. So I had the chip reflashed (gmeproms) and put it back in the original ECM. Then it still ran bad and I started swapping sensors, etc... thinking something else was wrong, not going back to the spare ECM. I started thinking the MEMCAL itself was bad. Had a MEMCAL built by jhonnybgood on facebook. Plugged that into the original ECM and still barely ran. Jabbed the original (now reflashed) MEMCAL into the spare ECM.....TADAAA! Just like that it's back running right. Confusing to read I know. I am over trying to figure out the how/why, just happy it's running again.

                      Comment


                      • #12
                        Originally posted by green73 View Post
                        So, apparently that jump start a long time ago did something to the PCM and the ECM. In troubleshooting, I put the MEMCAL in the spare ECM and the problem followed the MEMCAL. So I had the chip reflashed (gmeproms) and put it back in the original ECM. Then it still ran bad and I started swapping sensors, etc... thinking something else was wrong, not going back to the spare ECM. I started thinking the MEMCAL itself was bad. Had a MEMCAL built by jhonnybgood on facebook. Plugged that into the original ECM and still barely ran. Jabbed the original (now reflashed) MEMCAL into the spare ECM.....TADAAA! Just like that it's back running right. Confusing to read I know. I am over trying to figure out the how/why, just happy it's running again.
                        WOW! Good job hanging in there until you have it running correctly again. I have been following along and wondered what your trucks problem could have been. So It ended up being a memcal and ECM issue both right?

                        Comment


                        • #13
                          Originally posted by wildphil View Post

                          WOW! Good job hanging in there until you have it running correctly again. I have been following along and wondered what your trucks problem could have been. So It ended up being a memcal and ECM issue both right?
                          It kind of appears that way. Never seen anything like that. I would have assumed whatever voltage spike would have stopped at the ECM. It's very weird because it would start and drive (although horribly). It progressively got to the point it would just idle though. Initially I could get data from the ALDL for only a few minutes. Eventually there was NO, ZERO data making it to the ALDL in the end. It odd, I was looking at real time data on ALDLscan and it just stopped and timed out and never came back. I guess in the end it's obvious the ECM was bad, but I was focused on it being the EPROM alone. Oh well, now I gotta tune out some break-up while building boost above 8psi.

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