Megaswitch v.megasquirttesting

I'm starting a thread about Megasquirt since I now have a couple of them.

A number of months ago I acquired an MS1 v3.0, and have been trying to get my hands on an MS2 daughter card. I do have a contact in the US that has one, but with the way exchange is right now, it's just more than I want to spend on it. Once the dollar gets closer to par, then I'll buy it, if he still has it.

Anyway, I've noticed an MS2 on kijiji semi-local for a while now. I finally sent him an e-mail and we made a deal. I picked it up last night. It's an MS2 v3.0, that is set up for a Miata and has a custom Miata adapter plug 'n' play box, which I don't plan to use, but is rather interesting in itself.

Now my plan is to use this in my 1973 Datsun 240Z that has a turbo LX9 swap (3.5L from a 2006 Pontiac G6), and is currently running off a Delco 1227749 using $59 (code59.org). It runs quite well with the current set-up, I've just wanted to play with a Megasquirt for a long time. There were just some features it lacks that kept me from getting one, at least at new full price. I got a couple pretty decent deals between the 2 that I have now.

Anyway I plan to document the switch over and what challenges come up along with solutions. I also plan to make comparisons between the MS2 and the '7749 with $59, I may even compare it to another ECU I have access to, if I find time (Haltec Platinum 1000).

I'm going to start with pictures.

Both units, along with the Miata adapter, which I may show off in a separate post, if there's interest.
http://www.gearhead-efi.com/Fuel-Inj...0&d=1440896235

Both units with the covers pulled off. The extra circuit on the left MS (MS2) is for some Miata specific need, that actually increases the frequency of the PWM signal.
MS2 on the left and MS1 on the right.
http://www.gearhead-efi.com/Fuel-Inj...8&d=1440896507

Close up of the Miata prepped unit. (There's more jumpers on the bottom)
http://www.gearhead-efi.com/Fuel-Inj...2&d=1440896235

Close up of MS1 unit
http://www.gearhead-efi.com/Fuel-Inj...3&d=1440896235

Backside of the MS1 board
http://www.gearhead-efi.com/Fuel-Inj...5&d=1440896235

Comparison of MS2 daughter card (left) and MS1 CPU (right)
http://www.gearhead-efi.com/Fuel-Inj...6&d=1440896235

Underside of the CPUs
http://www.gearhead-efi.com/Fuel-Inj...7&d=1440896235

I've been interested in MS for a while too. Look forward to this thread.

Initial notes and plans:

After doing some initial research, I'm going to use the MS1 unit, with the MS2 daughter card installed, effectively converting it to an MS2 v3.0 unit. I have a few reasons for this:
-This particular unit has the hall effect and VR circuitry already installed, which is needed for the ignition set-up on my car
-I want to look closer at the Miata prepped unit and research it without disturbing it right now, because I like to know stuff.
-If someone comes along that needs the Miata prepped stuff and adapter then it will already be good for them and no need to add it all back in.
-Using the basic unit is closer to how most people would receive an MS, or if they had an MS1 and want to upgrade this information could prove to be helpful.

One big thing that is of note is that the MS2 is capable of running a stepper motor IAC, which most GM systems use. This requires a 12V feed to the MS daughter card, for the stepper motor driver. (Labeled UDN2916 in the below diagram).

http://www.gearhead-efi.com/Fuel-Inj...9&d=1440897934

The MS1 does not require a 12V feed and if the MS2 12V feed modification is made then an MS1 CPU installed it will damage the MS1 CPU. the modification is running a jumper lead to pin 16 of the 40 pin main CPU socket. Luckily on the v3.0 board this has been thought of an the jumper that is needed is very short between a hole labeled JS9 and another hole nearby labeled S12C.

Here are the two points that need to be connected (Underside of the board):
http://www.gearhead-efi.com/Fuel-Inj...0&d=1440898675

And relative to the rest of the board:
http://www.gearhead-efi.com/Fuel-Inj...1&d=1440898675

I've had an MS2 sitting in my shop for a few years now. Someday I need to find a good project for it. Keep us updated on your progress!

Coool, I have a customer with a Ford 460 that is getting swapped to MicroSquirt this winter. It should be fun, no stepper control needed and its already batch fire.

Thanks for posting this up.

I've been doing a lot of reading about options and such for the MS over the last couple of days, and it seems prudent to simply get the MS connected to and running the engine in a very basic set-up, with no options other than efan, since I have no other easy way to control it. Then after I have proofed out the trigger in, then move on to adding options, such as boost control, shift light, etc.

I do have both a stimulator and a JimStim (I've been using the JimStim for years with Delco ECMs), so I can do bench testing, but in car testing could come up with different results.

The really confusing part at this point is what code version to use, B&G code or MSExtra. I'm leaning towards the Extra code because it seems quite popular and well supported.

There seems to be some ignition settings that change or get inverted between the B&G code and MSExtra, that causes people to have issues, if they switch between them.

I was thinking about installing a jumper for the 12V feed to the MS2 daughter card, in case I wanted re-install the MS1 CPU, but the more I read about the limitations of MS1, I don't think I will be, at least not in an in car situation, where I wouldn't be able to easily use a soldering iron to remove the jumper.

I am considering using the MS1 on another project that either doesn't require an IAC or I could adapt a PWM type easily. I was originally considering using a '7730 for that project and still am, but the Alpha-N capabilities of the MS might make it easier to run.

I'm hoping to get to the necessary board mods tonight or early this week, to test in car, but will need to build an adapter harness as well, since I want to be able to easily swap between the '7749/$59 and the MS2.

I am intrigued by mention of 6 cyl sequential COP, using MS2.... I can see very quickly needing to upgrade to MS3, just to get more inputs and outputs to use some of the additional features. lol

To be honest, there's nothing going on in your setup that MS1 can't handle except the stepper idle control. That said, MS2Extra is the best supported system and can do everything MS3 can do with added on hardware, but it gets messy fast. If you are wanting to go full sequential don't even mess with an MS2, just make the jump now. Nothing interchanges between them as far as wiring or coding.

There are a LOT of errors in the documentation you find online-use only the official MSExtra documentation. Some of the old wiring diagrams and methods result in unusable noise problems-and MS2 is MUCH more sensitive to noise than MS1 was. Good grounding practices are not enough in every case, the biggest noise problems are from using low-z injectors and the way the traces are routed on the PCB. Hopefully you won't have issues with yours.

The standard MS2 code does not support every type of trigger wheel, nor does it have a really good handle on warmup control-MS2Extra does it much better.

Yes, IAC is very important to me, which is why I never even bothered with the MS1, and I didn't want to try and adapt some other IAC to it, since I knew I wouldn't stay with the MS1 anyway. I'm not even planning to keep the MS2 on there, it's simply to get more hands on with MS, and get to know the any quirks. Unless I find some glaring limitation of the Delco ECM, the '7749 will be the go to ECM in my car, the MS install is temporary.

I'm not planning on using low-Z injectors and if I ever do, I will build an external driver circuit anyway.

I never though some MS hardware would make it to your desk Chris, let alone your car, that's awesome :rockon:

For having run MS1 and MS2 and MS3 for some time, I would personally go with MS3 right away but just because I like to have the most fancy stuff :P Some features are quite interesting tho (AFR safety, SD card data logging are probably my two favorites that "can't" be done on MS2). The gap between MS1 and MS2 is a lot bigger than MS2 and MS3 in my opinion tho. MS3 does have the MS3x that make it easy to do all sort of cool thing (like running SFI).

Anyway, if you have any questions, you know where to find me :) I saw you were hesitating between B&G code and extra firmware. It's not even a question, go with the Extra code. msefi.com vs msextra.com is the biggest non sense ever but just forget about msefi.com, just use msextra.com. Also, the documentation got A LOT better in the last year (for msextra).

I highly doubt you will go back to your delco ECM but I guess we'll see!

3400ttZ; I've been following MS since it was called EFI-332, which fizzled out and some of the people involved there developed the MS1 and then you know the rest. There were just a lot of problems and limitations of the early MS, that kept me from trying it. Even the MS2 doesn't have some features that I would like, but the MS2 use is just for the hands on stuff.

Anyway, I haven't done a lot lot with this, been busy with some other things. I did decide to install a jumper for the 12V feed to the CPU/daughter board so I can do easy swaps on the bench for comparing MS1 to MS2. I also added the IAC jumpers.

I still need to set up the E-fan and boost control outputs, along with verifying the ignition circuits are correct for the ignition I will be using. I also need to set it up to work with a friend's car that I want to test this on, that is very different from my car...

http://www.gearhead-efi.com/Fuel-Inj...0&d=1441645861

http://www.gearhead-efi.com/Fuel-Inj...1&d=1441645861

http://www.gearhead-efi.com/Fuel-Inj...2&d=1441645861

Well, it seems I REALLY need to update this.

No I don't have the MSII in the car yet, but I am getting closer to getting to that point. School and life has delayed getting as far as I would have liked by now.

I do have updates though.

I'll start with something that doesn't change functionality of running the engine in the slightest but will will with a future modification that I will get to later. That is socketing the MAX232 IC (U6). When I got this board the MAX232 IC was soldered directly to the board, and I have plans to change the way this circuit functions so I figured I'd install a socket to make that later modification easier.

U6 removed:
http://www.gearhead-efi.com/Fuel-Inj...1&d=1446969701

U6 socket:
http://www.gearhead-efi.com/Fuel-Inj...2&d=1446969701

Max232 in the socket:
http://www.gearhead-efi.com/Fuel-Inj...3&d=1446969701

After doing this I then moved onto the ignition connections. I had to sort through a bunch of pages of the MSExtra manual to weed out what I needed to do. I have not testing this in the car yet, but bench testing shows that it should be good.

Anyway, I started the TSEL jumper, and it gets put between VROUT and TSEL. This is connecting the VR conditioning circuitry to the Tach in signal of the MS CPU.
http://www.gearhead-efi.com/Fuel-Inj...4&d=1446969701

I then moved to the TACHSELECT jumper. This gets connected to the VRIN pin to pass the incoming RPM signal to the VR conditioning circuitry.
http://www.gearhead-efi.com/Fuel-Inj...5&d=1446969701

So at this point a signal, which will be the EST signal from the GM ignition module can be run into the MS CPU, but we need a way to actually control timing, so there's a couple outputs that need to be created, or modified using some existing circuitry on the board.
This is where D14 and D16 and related circuitry gets modified.
I started with the IGN output, this will be the ESC signal that connects to the ICM and gives the ICM the needed timing signal info.
I didn't like the way the manual described the modification, adding another resistor on top of what was there, and after drawing out both the original circuit for D14 and the new modified circuit and convincing myself I was correct, I removed R24 to replace it a 1K ohm resistor, since the original R24 a 330 ohm resistor will become superfluous. This location was perfect for putting in the new value of resistor. I also hate the bodged look, so I try really hard to make the modifications look like they were not afterthoughts. Anyway, after replacing the resistor I then jumpered the two pins that the LED was originally attached to, to create a point that I can attach a wire to. This jumper is on the bottom of the board, since the other end of the jumperpoint was easiet to access from the bottom and I am trying to keep as many jumper wires on the bottom as I can.
http://www.gearhead-efi.com/Fuel-Inj...6&d=1446969701

I then attached a jumper from the loop I created and attached the other end to the IGN point. This allows the new trigger circuit to actually be passed out through the DB37 connector.
http://www.gearhead-efi.com/Fuel-Inj...9&d=1446970870

Almost there for ignition and timing control, one more circuit to modify, this time D16. Once again I removed the 330 ohm resistor at R28 and replaced it with a 1K ohm resistor, and again I created a jumper between the LED pins to attach a wire to, this time on the top, since the SPR3 hole is easiest accessed from the top, due to the MAP sensor being mounted on the bottom of the board at this location.
http://www.gearhead-efi.com/Fuel-Inj...7&d=1446969701

And now, if everything went according to plan, tach signal in timing control should be taken care of.

I then turned my attention to the fuel pump circuit. I don't like how the MS uses a negative trigger for the fuel pump relay, a positive trigger was needed anyway, because of the way GM controls the fuel pump relay. Yes a simple relay in the adapter harness would have been fine to invert the signal, but a relay to simply control a relay just seemed overkill to me, even using a small signal relay.

So I decided I would modify the onboard circuit, because I could and I would be applying some things I've learned in school, so win...win?

Anyway. I removed transistors Q2 and Q19, these are both part of the fuel pump relay control circuit. Q2 is what actually controls the output, Q19 is there for over current protection, in case too much current is pulled through the fuel pump control pin. I also removed R40 and D4. R16 is fine and at 1K is perfect for the modified circuit anyway. R40 gets replaced with a 1K ohm resistor, D4 I replaced with a 1N4001.

I built the new circuit on a breadboard initially to test before building it in the MS, once tested and verified, I built the circuit in the proto area on the MS V3.0 board. It consists of two transistors, in my case I used a 2N3904 and a PN200, since I had them on hand. If you wanted the ZTX450 (removed from Q2) could be used in place of the 2N3904, but a PNP transistor will be needed for the final output control, the PN200 in my case. I chose this one because it was in a TO-92 case and it was the highest current rated I had on hand without going to a larger packaged device. The Ic of this transistor is -500mA, which is about 300mA more than the relay it will be controlling so I think this is a good match, if not, I'll use something else, so far it's tested well though.

I will get the final circuit posted for anyone interested, once I make one small addition.

Here are some pictures.

The slighter darker green wire in the middle of the board is the wire that will feed 12V out to the fuel pump relay:
http://www.gearhead-efi.com/Fuel-Inj...0&d=1446972493

I picked up the 12V feed for the circuit from the 12V pin one the banded side of D9, which is also attached to the 12V in of the 5V regulator. There are several other points that could be used, this one was just close by.
http://www.gearhead-efi.com/Fuel-Inj...1&d=1446972493

I then attached the other two jumpers from the Q2 location to control the circuit, base of Q2 going to the base of the 2N3904, the The emitter pin of Q2 to the emitter of the 2N3904. The collector of the 2N3904 is then attached to the base of the PN200. I want to add a pull-up resistor to this circuit to make sure that the circuit stays powered down when it's supposed to be.
http://www.gearhead-efi.com/Fuel-Inj...2&d=1446972493

And the top side of the board showing the two existing transistors.
http://www.gearhead-efi.com/Fuel-Inj...3&d=1446972493

I have more done, but I think I'll wait until tomorrow to post any more.

I added the boost control circuit to the MS.

Typically the instructions suggest using jumper wires directly to the transistor or MOSFET being used, then drilling a hole in the case to mount the device. As you can imagine if you've been following along this isn't my style, so I looked over the board and realized that I'm not using the high current coil driver (Q16), and probably never will, since I don't plan on using any single coil ignition systems. The pads for this driver are also isolated from other circuits, so it's easy to use any TO-220 packaged device. So I removed that driver and replaced it with a MOSFET, an IRFZ44 following the Diyautotune boost control circuit diagram, I added a jumper between the drain (IGNBTOUT) of the MOSFET to the SPR4 output pin. The source pin that comes out at R43 and a simple jumper was added here to the other side of the R43 footprint, this provided a ground source.

http://www.gearhead-efi.com/Fuel-Inj...9&d=1447027333

To control the MOSFET I used the JS11. The gate circuit needs two resistors, one that is in series and one that attaches to ground. For the one that pulls down to ground I used the R57 location for the 10k ohm resistor, and installed the 100 ohm resistor in the proto area. I hate resistors floating around, or inline in jumper wires. It also makes it easier to change the values if I ever need to when they are soldered to the board and easily seen like this.

http://www.gearhead-efi.com/Fuel-Inj...1&d=1447027333

Anyway a couple jumpers later and the boost control hardware is installed. The grey/yellow wires in the picture below:
http://www.gearhead-efi.com/Fuel-Inj...0&d=1447027333

And the circuit I'm using:
http://www.gearhead-efi.com/Fuel-Inj...2&d=1447027630

no flyback diode? I didn't think I needed one to control an EGR solenoid, I burnt my fingertip when I touched the FET controlling it.

There is an internal diode of the IRFZ44, that I believe will act like a flyback diode. If not, no big deal, I'll add one if the IRFZ44 ever fails. Also the FET getting warm is not really to do with the precense of a flyback diode or not, but to do with the current flowing through it. The flyback diode only protects against those large voltage spikes that occur when a coil is switched off and causes the spike to dissipate within the coil/device itself.

the exact FET I was using was a STP65NF06, which is also a N-channel MOSFET and has a body diode the same way a IRFZ44 does. I thought the same thing until I burnt myself, did some google-fu and ended up here:

http://electronics.stackexchange.com...-or-transistor

the right diagram essentially has the body diode of the FET accounted for and is listed why it doesn't quite work(unless it's a zener). the STP unit's datasheet says the body diode functions as an avalanche, but I either did something very wrong or it isn't sufficient. the solenoid was also very non-linear in response, which is the opposite of what I expected. added in a 1N4007(as shown in the left diagram) I had from my diode selection and suddenly the solenoid operates with almost complete linearity from ~20% to 80% duty cycles and no more scorched fingers. without the diode, the solenoid was buzzing like crazy when commanding a duty cycle between the ranges of fully closed and fully open(which was something like 50 to 70%).

something to test on the bench, if you really wanted to, I was much happier finding this out before calling a project finished.

Interesting, but I think the zener diode is making the valve more linear by changing the way the load is seen by the source. I'll have to think about that for a bit, maybe even do some testing A flyback diode is supposed to be invisible to the source and only be conduction when the coil is discharging immediately after current is taken away from the circuit .

So, since RS232 is pretty antiquated I wanted to get around the need to use a USB to Serial adapter, especially since every off the shelf adapter I've bought seems to either not work at all or be flakey.

This is where that earlier modification of socketing the MAX232 IC (U6) comes into play. My plan was to replace U6 with a second DIP socket with the correct four pins jumpered to pass a TTL signal straight through from the db9 connector to the MS uC. I have an USB to TTL signal converter from Spark Fun, based on the FTDI FT232R IC.

Initial testing of the idea:
http://www.gearhead-efi.com/Fuel-Inj...4&d=1447046021

3 wire connection, ground, TX and RX:
http://www.gearhead-efi.com/Fuel-Inj...5&d=1447046021

Test jumpers inside the MS:
http://www.gearhead-efi.com/Fuel-Inj...6&d=1447046021

Replacement DIP socket to pass TTL coms straight through:
http://www.gearhead-efi.com/Fuel-Inj...7&d=1447046021

Adapter DIP installed:
http://www.gearhead-efi.com/Fuel-Inj...8&d=1447046021

While initial testing proved that it works for communications between the MS and the computer, there's an issue with early MSII daughter cards (which mine is) in that if there is no 5V present on the RX pin of the MS II daughter card at power up it goes into bootloader mode. This means that either the breakout board I have always has to be powered up, or a modification needs to be made to apply 5V to the RX pin when it's not powered up. Which is not a problem if I leave the breakout board in the MS all the time, but that was not the plan. I use this board for other devices as well, and I'm too cheap right now to buy another or several. lol So my idea of bypassing the MAX232 IC in the way I wanted was not going to happen. I came up with a few different ways to apply 5V to the RX pin without the breakboard installed, and then disabled once the breakout board was then plugged in, but this would be more proprietary than I wanted. ONLY my adapter would then work with the MS and that will usually not be a problem, but I didn't want to take any chances, so I went with an alternative, I created my own USB to RS232 adapter... well I've breadboarded it so far. I still need to make a more permanent version using some proto board.

My adapter is the same USB to TTL breakout board I used earlier but I'm using another MAX232 IC to convert the TTL levels to RS232 levels that the MAX232 IC inside the MS can then convert back to TTL levels. yeah I know it seems odd to convert up just to convert back down again, but this way if my adapter isn't available for whatever reason and someone else's is, it will still work just as if it were normal. I also have a Blue Tooth TTL board that I used in a school project that I'd like to get working, but need to reprogram the baud rate before I can get that working and I need to look up again how to do that. lol

the overall USB to RS232 adapter breadboarded and communicating:
http://www.gearhead-efi.com/Fuel-Inj...9&d=1447046021

Just the guts of the main adapter circuit:
http://www.gearhead-efi.com/Fuel-Inj...0&d=1447046021

I've had this circuit working on my bench for several hours how and it's worked flawless, zero drop outs with my main PC and only a couple drop outs with my laptop, but that's far less than with the USB to serial adapter I tested earlier today which is a Prolific based adapter, which are always flaky at best. I had drop outs every couple of minutes with the Prolific adapter, just monitoring basic coms.

Yep, always use FTDI USB chip (which I believe this is what your breakout board is now ?!). Prolific drivers are not so great on Windows and even worse on Android :)

You seems to be having fun with that MS Chris. Also looks like its getting closer and closer to make it to your car :D

Yep, my experience is the same, FTDI or nothin' It just seems that people, myself included end up with Prolific junk. Oh well.

I've just been playing with it on the bench to get used to the software, and figure out what makes the MS tick, and make sure everything works the way I expect.

I've even upgraded the firmware. When I got this MSII it had FW version 3.0.3u, so, it's OLD, that FW is from 2009 if my findings are correct. I loaded the latest (why wouldn't I use the latest? lol) 3.4.0.

I still need to register TunerStudio, I mostly want the custom dashes/gauge layout. I don't really care about auto tune, though I might as well use it with the registered version...

I figured I should update this a bit, since I have something to update.

Well, the original plan for the MS was to install it on my LX9 in my Datsun, but since that's been broken since December with no sign of getting back together anytime soon, due to reasons, which are beyond my control right now, I installed the MS on my T-bucket (283+.030" V8) which I converted to EFI about a month ago using GM components, including a '7747 ECM. I used the Delco to start with because I knew that it should be close and could drive it on the stock tune, or tune it a bit better, and then switch to the MS. Both of my widebands were also loaned out in other people's vehicles at the time and didn't want to try tuning the MS blind, so another reason to start with the Delco at the time.

Well there were mechanical issues that needed to be worked out and at this point should be pretty much solved. I got sick of the '7747 losing connection with the AutoProm and lack of reliable datalogging. There might be an issue with the ECM itself, but I was just sick of it. This was last Friday. I went home and started on an adapter to jumper the '7747 harness to the MS. I'll post pictures later.

Sidenote: When I installed the Delco EFI I knew I'd be going to the MS shortly so I added wires at the time for the IAT and a couple extra grounds.

On Sunday (I was lazy on Saturday lol) I finished the adapter harness and ran a vacuum tube for the MAP sensor that is built into the MS ECU. I was able to get the engine to start and run ok, in trying to tune the '7747 I discovered that increasing MAP AE worked very well to get rid of a lean pop through the intake with large throttle changes, so I started there by figuring out how to enable the MAP AE in MS. Turns out that there's a slider in the AE menu that controls the blend between TPS and MAP AE, and you simple slide it towards the MAP AE table...

One thing was always a miss though, above about 3000 RPM, the revving became REALLY sluggish, and no matter what I tried with VE or spark nothing changed it considerably for the better.

I checked base timing and decided to adjust it. I ended up with a weird thing where with the bypass connected the engine would not start, the MS was not getting or at least was not acknowledging any RPM (DRP) signal. Bypass disconnected and the engine would start and run the way that was expected.

In this I decided to check whether the EST signal was good from the MS, which I used my JimStim and connected the EST signal to a spare LED on the JimStim board and observed the LED pulsing... for hours, in fact overnight the EST signal was still triggering in the morning... oopps... lol

I also discovered that the MSExtra manual is wrong where the bypass control circuit is concerned. Using the board modifications and the external connections shown will have the timing control work backwards, as in ECU controlling timing during start, but not during run. *facepalm* This is why the engine seemed lazy above 3000 RPM, because it was running on base timing! In other documentation there is often a relay suggested to control the 5V signal on the bypass line, usually the relay is suggested to be controlled by the ignition switch, so that 5V is provided to the bypass wire only while running, so that base timing is still used at start. diyautotune.com suggests connecting the bypass wire straight to 5V and have the ECU control timing during start up.

I went a different route. The built in settings for the HEI control will turn on the transistor that controls D16 (Q8) 5 seconds after the engine starts to run, or more specifically after the threshold that is set under "Cranking/Startup Settings" called "Cranking RPM" has been exceeded. IIRC stock setting is 700 RPM, I set this to 400 RPM. As I mentioned before the way the MSExtra manual suggests to connect it will not work correctly. I modified the circuit by installing a 2N3906 PNP transistor to provide the 5V on the bypass line that is needed for the ECU to control timing through the HEI module. I have not tested this on the engine yet, hopefully tomorrow I will be able to. On the bench it works it works perfect and I can't see the HEI module needing anywhere near the 200mA rating of the 2N3906 transistor.

I will post pictures and hopefully a schematic tomorrow, once I get a chance to get them onto my computer.

Just to update this...

I gave up on trying to get the 283 to run right. It was old and tired. I replaced the timing set, a friend of mine played with it for a bit, adjusting rocker arms because the lifters seemed to be pumped up and would not bleed back down making them act like mechanical (solid) lifters. At one point the engine was literally a V-twin, only cylinders 1 and 2 seemed to actually be firing. I gave up and left the car alone for a while.

Last week I had holidays, and my Grandfather's truck had a good running 305 in it, that was destined to be replaced with a Vortec 5.7L that had been installed in the truck years ago but pulled due to a crack in the block for the starter bolt. That's fixed now and using a different starter now that uses different holes seems to have taken care of that issue. So I swapped the 305 out for the 5.7, and then took the 305 and swapped it in place of the 283 in the T-bucket.

So now that it has a good running engine, I reinstalled the MS, and fired it up. It ran ok, then noticed that the bypass wire was still disconnected, I reconnected it and the engine stalled. Tried a few different things, stalled every time. Then used a meter to check the signal on the EST circuit and found there was no output, no wonder the engine would stall when it was looking for that output. Opened up the MS to find that the transistor driving that circuit had failed (small hole in it that had blown out). replaced that and the car runs well. Still needs some tuning but I have driven it everyday since Sunday, because I can and it's fun to do so now, unlike before when the 283 was in it and it would get worse and worse to drive as time went on.

Couple pictures. The wiring will be cleaned up in the winter, it works for now, so it's good until then.
http://www.gearhead-efi.com/Fuel-Inj...0&d=1471655926

http://www.gearhead-efi.com/Fuel-Inj...1&d=1471655926

I've been playing with the T-Bucket and making some adjustments to the MS when I get the chance to.

It's running well. I've added a lot of timing and the engine loves it. I can get away with this because the car is so light it doesn't really put much of a load on the engine. Still needs more though. It fires up every time the same way, little bit of an extended crank when cold, but then quick to fire on warm/hot restarts, runs as high as about 190 degrees F, when in stop and go or sitting and idling, cruising is generally down closer to 170ish.

I've also been using my phone with MSDroid to make small adjustments and datalogs. It's been dropping out at certain points, usually just above 3000 RPM, but not every time. I have a couple ideas on things to try to get that to stop.

So far the MS has been good. Unfortunately I can't really directly compare Delco to the MS in this application like I wanted to do when I started this thread since I never had the Delco running on this engine, well, I did, but for about 35 seconds just to get it to fire, since I knew the calibration would be close, and I didn't have one of my WBO2 sensors to install to use with the MS to get it tuned.

But I can pretty much say that the outcome and use were pretty much what I expected going into this.

Both systems have their pros and cons, I still like both systems for different reasons.

The Delco I like the fact that it has a true RDF/LHM mode (Limp Home), that DOESN'T rely on the CPU being fully functional, or even a proper bin on the EPROM being present. The MS1 and MS2 don't have any sort of LHM, and the MS3 has a quasi LHM, that will allow substitute values if a sensor or multiple sensors fail, which is better than nothing at all, but still relies on the CPU to fully functional.

The Delco is cheap to acquire, install and even tune, although like anything, you can throw good amounts of money at a Delco for tuning as well, such as using Emulators and other related bits.I also like the fact that you can buy a replacement Delco ECM pretty much anywhere, IF you ever have one fail. In my time of using Delcos I've only ever had 2 fail where it wasn't my own stupidity causing the failure, and even one of those failures, could be sorta blamed on me, when I had some rain water drip onto the ECM, where as if I had the ECM mounted where it should have been, it likely wouldn't have been an issue. The MS can be done inexpensively as well, especially if you buy used, but buying MS used is a bit of a gamble, due to the universality of the MS, it may need extensive recofiguing of the hardware to use on your application, and as long as you're proficient with reading schematics and soldering, that's a great way to go. The other issue is that someone who isn't that proficient may have caused damage to the MS ECU and now you need to deal with it or even find the problem.
I've bought several MS1 and MS2 ECU and even a DIYpnp over the last year, the most I've spent on a unit has been about $170 USD, with shipping. The deals are out there. I've bought a couple locally, because again they were good deals. However this seems to be atypical, especially when it comes to the specific versions I have been buying. I just find them at the right time and jump on them. This again is where if you're proficient with reading schematics and soldering you can buy ECUs that are reported to be not working, damaged, etc and repair them. I bought one MS2 V3.0 because the guy bought a DIY kit, and wasn't very good with the soldering aspect, so he damaged the main board. He was upfront about this, but it came with a never been used MS2 daughter card. He never got to the part in the assembly where it gets plugged in before giving up and buying a pre-built unit. I figured at the very least I was spending just a little more than just buying the MS2 daughter card and it was worth it that way to upgrade one of my MS1 ECUs, even if the mainboard was a total loss. The board was pretty badly damaged in to spots, over current transistor for the fuel pump output and the MAP sensor pins. This worked out though since I want to install an electronic trans in one of my vehicles so I am re-configuring it for trans control use. I had planned to run that vehicle with '7749 and $59, but now I will likely also run it with MS, so that I can use the CANBUS between the UCU and the TCU to save on connections and be able to take advantage of some of the trans control features, I'll see when I get to that point.
I bought a broken DIYpnp for about the price of shipping because that's all teh guy wanted. I haven't been able to verify everything that is wrong with it yet, but since I like to play with electronics I figured this was worth the price, especially since I've wasted more money on less fruitful en devours in the past. lol Since I can communicate with the CPU, I think I'm hoping that the I/O will all be good and hopefully just an external driver is bad. I need to set up a testing adapter to plug into my JimStim to feed it actual sensor signals though.

Tuning:
Tuning one is no easier than tuning the other IMO. Once the engine is up and running tuning is about the same between each, mostly working with the VE and spark tables, and making other minor adjustments to start up enrichments, AE, DE, etc are all very similar, and in some case just the same. The biggest difference to remember when tuning a Delco is that the VE numbers stop at 100 (99.8 actual IIRC), and any number above that gets truncated to the 100 value, where as the MS allows higher than 100 values in the VE table, I don't recall what the actual limit is, but I bet it's 254 (8 bit maximum). I know this max VE of 100 has caught some people in the Delco world a few times. Simple adjustment to the BPW, or the base calculation (differs in some Delco applications) and you can them get the values all below 100.

So far I have not used any of the "extra" features that wouldn't be present on a Delco, no flat shit, or anti-lag, nitrous control, boost control, etc, since I have no turbo, nor nitrous and it's an automatic, so nothing to really control there. I will be playing with these features on the next MS equipped car, my Datsun, once I finsh assembling the engine which is nearly complete. I will be testing anti-lag, flat shift, etc

So both systems are good, one requires more electronics knowledge, due to the needed internal modification (*except MS3Pro), where as the other requires more hardware knowledge to use in a non stock application. So pick your poison, and if you need some of the features that the MS has that the Delco doesn't, well then you'll need to look at another option, such as the MS3Pro, if you really don't want to get into soldering up circuits.

Just to mention the MS3Pro, it has all of the features of the MS3 WITH the MS3X board added on, but in a moisture proof case with AMPseal connectors and nothing to modify on teh board to get any and all functions to work. What it does require though, is the ability to add on external circuits depending on what you are trying to run. Some injectors will require injector driver boxes (for Low-Z), or add on coil control boxes/ignitors, for "dumb" coils, relays for many of the simple on/off circuits. I've installed one of these on a friend's car that previously had a FAST EZ-EFI 2.0, and it runs SO much better with the MS3Pro, though we also did swap to MPFI at the same time, so I'm sure that was a factor as well. If I had the money I'd likely go MS3Pro, but I don't, so I'll use the DIY version, and that way I do get to play with the soldering iron and electronic bits I have on my bench which is fun for me.

I have been told that the MS2/MS3 is much faster to react to changes in engine state (like throttle input) than a 7747 Delco unit, making throttle response almost as instant as on a carb. Can you confirm this?

I can't say that I've noticed any difference there.

Honestly the processor speeds are much higher than need be for any of the three systems you mentioned won't affect throttle response. There are MANY, MANY other factors that will affect that more than processor speed.

Quote:

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Originally Posted by Six_Shooter

I can't say that I've noticed any difference there.

Honestly the processor speeds are much higher than need be for any of the three systems you mentioned won't affect throttle response. There are MANY, MANY other factors that will affect that more than processor speed.

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OK, so I should rather focus on getting my AE settings right, I guess.

Quote:

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Originally Posted by Dr_Grip

OK, so I should rather focus on getting my AE settings right, I guess.

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Yes, AE, VE, timing, etc will all have a larger effect on throttle response than what system is used. :)

on a 7747, TPS is updated at 80Hz, correct? assuming the engine is running at 2000RPM and you jump from 10% throttle up to 100% in 1/10th of a second, the TPS is going to be read and acted upon 8 times in that scenario.
the engine is going to complete 3.333 revolutions in that 1/10th of a second.
the engine is going to make .417 revolutions between TPS updates at that speed.
with a 6 cylinder, that's 1.25 ignition events between updates. with an 8 cylinder, it's 1.67.

you would have to be able to feel 1 or 2 fuel/ignition events being less than optimal for there to be any sense of improvement. a hard miss is easy to detect, but a very mild misfire is awful difficult to detect.

if the TPS read is done at 160Hz(some GM OBD1 ECMs do this), then even with a V8, you're at less than one fuel/ignition event before the TPS is read and accounted for.