Megasquirt - 2g with 1g swap - COMPLETE and RUNNING

[skye]

I'll have more details wrote up soon, but mine is running fuel and spark and it's running way better then it ever has before.... was done with the help of dieselgeek on this board!

Not sure if anyone else has completed this before, but it's great and it actually eliminated all the headaches I was having with all the issues with my swap, no more random misfire, no more CELs....

 

[monotalonawd]

Glad to hear that!

I just received the kit, now I need to solder and assemble it.

 

[ISUJakey]

Great to hear Rachel! Now you need to post on your results on DSMStyle as well as here since you used to keep in touch with us DSMStyle.com folk.

 

[highbooster]

Good job. Nice to see someone did it. What if any problems did you run into? Thanks in advance. Allen

 

[dieselgeek]

only issues with Rachel's install so far have been unrelated to MS:

we smashed a coil power transistor reinstalling the transmission. Oops.

Then we had a strange coilpack mounting location that caused the hot lead to one of her coilapcks to short to ground, and it messed up one of the coils (it has more resistance than the other coil now)... we played with a 1G coilpack using the 2G transistor, and some different dwell settings, and overheated the coil transistor but ran out of time - so she's running on the 2G transistor and coilpacks until we get together next to either (a) measure the factory ECU's dwell settings and duplicate them in megasquirt, so as to keep the transistor and coilapcks happy or (b) switch back to 1G coilpacks, with 2G transistor, and figure out the dwell setting that keeps that config happy.

Too little dwell and you get spark blowout. Too much and the transistors overheat at idle. We got Prez's setup dialed in by using an oscilloscope to measure and duplicate the dwell in the megasquirt.

 

[Maglin]

Wow I'm impressed for sure. I'm kind of waiting for UMS to come out before I give it a go. The Target ARF with WB is going to be very nice. Since I already have a WB I could use MS2 but I want to wait and I'm hoping UMS has knock retard as it's a nice safty measure to have.

Let us know some of the problems you had getting this thing hooked up. I was planing on using a ECU harness connector from a Bad ecu as to make the UMS Plug and Play. So can the MS2 run 2 coil packs independent of each other? I was under the impression from what I read that it can only control one coil pack at this thim.

What sensors did you have to change out to make the MS work? I know you needed a IAT sensor. Did you use a sensor mounted to the PCB? Or did you go with the GM sensor?

 

[dieselgeek]

Wow I'm impressed for sure. I'm kind of waiting for UMS to come out before I give it a go. The Target ARF with WB is going to be very nice. Since I already have a WB I could use MS2 but I want to wait and I'm hoping UMS has knock retard as it's a nice safty measure to have.

Let us know some of the problems you had getting this thing hooked up. I was planing on using a ECU harness connector from a Bad ecu as to make the UMS Plug and Play. So can the MS2 run 2 coil packs independent of each other? I was under the impression from what I read that it can only control one coil pack at this thim.

What sensors did you have to change out to make the MS work? I know you needed a IAT sensor. Did you use a sensor mounted to the PCB? Or did you go with the GM sensor?

Well, I've got some great news for you... all the features of UMS are available on a regular old megasquirt. What you do is reinstall the firmware on the megasquirt, using the "Extra" version of megasquirt firmware found at http://megasquirt.sourceforge.net/extra

Read about all the features on that page. This is what Rachel and Prez are running in their MS units. In some cases to take advantage of the features, you need to add a few components to complete the circuit... for example, the knock sensor circuit. But you can also buy the knock sensor circuit as a kit for $60 and only have to attach a few wires to make it work...


but all the features you mentioned are available in the current, plain old megasquirt.

It should be noted, that Megasquirt -II is out, but has nowhere near the features of the basic megasquirt (basic MS is a Version 2.2 board) - this is because all of the extra coding has been built on the basic MS. Here in a year or so, the MS-II should have the "Extra" software ported to it - and then it will be the unit you want. Until then, for anyone who is comparing Megasquirt to an AEM, Link, DFI etc. should stick with the basic board, which is in use on thousands of cars now, and has been tested and improved upon to reach the reliability it gives today...

-scott

 

[Maglin]

Thanks for the Link Dieselgeek. Wealth of info from their. Did you use a new harness for your install or did you splice into the OEM harness? What kind os ignition setup are you using? At frist I was thinking 420A/Neon but the more I look at it is looks like EDIS. Where you able to use the power transistor that we have stock. It appears to be the bosch unit that has the dwell control built into it. I have a ton of questions for you. I'm looking forward to the write up soon. Most of it is very straight forward. I'm mainly confused about which ignition we should use. I'm going to have to do some research on how our CAS outputs it's signal. I would think it outputs on one wire 1 tick per rev and another 4/rev. One of ignition and the other for injector timing, but I'm just guessing right now.

 

[dieselgeek]

Thanks for the Link Dieselgeek. Wealth of info from their. Did you use a new harness for your install or did you splice into the OEM harness? What kind os ignition setup are you using? At frist I was thinking 420A/Neon but the more I look at it is looks like EDIS. Where you able to use the power transistor that we have stock. It appears to be the bosch unit that has the dwell control built into it. I have a ton of questions for you. I'm looking forward to the write up soon. Most of it is very straight forward. I'm mainly confused about which ignition we should use. I'm going to have to do some research on how our CAS outputs it's signal. I would think it outputs on one wire 1 tick per rev and another 4/rev. One of ignition and the other for injector timing, but I'm just guessing right now.

We used the "Second Wheel Decoder" to get a tach source and sync from a 1G Cam Angle Sensor (which is 2 sensors - Cam position, and Crank position {RPM}). From there, we used the "Neon OUtput Mods" on the megasquirt so it can use a 5 volt pulse to trigger the factory DSM power transistor, and thus the factory coilpacks. We set the dwell time to match the DSM ECU's preprogrammed dwell and have had no problems since.

Almost all the wires are tapped into the factory harness, right near the factory ECU. Some signals you share (T-tap, or splice): Throttle Position Sensor, Oxygen Sensor; others you remove entirely from the ECU: fuel injectors (4 wires), coil A and B. On Rachel's car, we ran our own wires for dedicated temp sensors, using GM temp sensors, inserting the Coolant temp sensor into the stock DSM CLT sensor location, and threading the intake air temp sensor into her intake piping.


-scott

 

[Maglin]

I've read what I can find on the MS boards on Prez's car. Man that video makes me giddy. That was one hell of a idle. Although the car didn't look to heavily modded. Ever since I installed my 1000cc injectors and the hugh FMIC and HX-35 I get some idle surge. Evertime I get it sorted out it the my low trims wack it out again. Surges cause it's lean as hell at idle and it doesn't take much at those engine speeds to stop fuel flow out of those hugh injectors.

Can you hook us up with some links for the pull-up resistors for the 12v and 5v CAS inputs? And maybe some config files for MT. I'm still pretty new to all of this.

 

[sherloc123]

how hard is it to tune a 1g with megasquirt?

 

[dieselgeek]

I've read what I can find on the MS boards on Prez's car. Man that video makes me giddy. That was one hell of a idle. Although the car didn't look to heavily modded. Ever since I installed my 1000cc injectors and the hugh FMIC and HX-35 I get some idle surge. Evertime I get it sorted out it the my low trims wack it out again. Surges cause it's lean as hell at idle and it doesn't take much at those engine speeds to stop fuel flow out of those hugh injectors.

Can you hook us up with some links for the pull-up resistors for the 12v and 5v CAS inputs? And maybe some config files for MT. I'm still pretty new to all of this.

You can search "pullup circuit" on google, there are some good sites that show you what the idea is... but it's very simple to hook up.


A 12v pullup with the CAS signal looks like this:

12V power source ------------------> 330 Ohm, 1/4 watt resistor --------> MS Tach Input
CAS RPM signal ---------------------------------------------------------/


5V power source ------------------> 330 Ohm, 1/4 watt resistor --------> MS CPU pin 11
CAS "Cam Position" signal ------------------------------------------/


pardon the really bad ascii graphics!!


Basically you just combine 12v or 5v power, using a resistor, to the CAS signal wire.

-scott

 

[highbooster]

can you build the megasquirt set up for a 1g dsm

 

[dieselgeek]

Uhhh... yes. Read the posts above, this is a 1G swap. I also did a completely 1G car, his name is "Prez" and I think you can read about it here.

 

[highbooster]

in your experience how does ms match up to the better known standalones you have tuned. aem, gems, haltech, motec ect...

 

[dieselgeek]

The ones I have the most experience are DFI Gen 7, and AEM. I did an OLD school haltech once.

I think the Megasquirt software is every bit as stable as the others, and it's a lot more intuitive/easy to do an initial setup. But the tuning interface on the AEM and DFI are just a tad nicer to use when tuning on the fly! The initial config on both AEM and DFI are *wildly* overcomplicated, considering there's no ignition system that they do that megasquirt can't. That's the one major diff I can think of. BUt once you've done any one of them successfully, you can work through any of the others without much difficulty.

 

[need4speedtsi]

Okay Im a little confused on the wiring. For the secondary tach input, did you just connect cpu pin 11 right to a pin on the db37, and add the resisitor externally, or did you do it inside the case? And for the leds did you solder a 1k resistor between the - leg of the led and the right hand end of R23 (+5v) (r27 for led19) then run a wire from the - leg over to X11? sorry if this is a dumb question, I just want to fully know whats involved before I go diving in to this.

 

[dieselgeek]

Okay Im a little confused on the wiring. For the secondary tach input, did you just connect cpu pin 11 right to a pin on the db37, and add the resisitor externally, or did you do it inside the case? And for the leds did you solder a 1k resistor between the - leg of the led and the right hand end of R23 (+5v) (r27 for led19) then run a wire from the - leg over to X11? sorry if this is a dumb question, I just want to fully know whats involved before I go diving in to this.

For the second tach input. I brought the CAS signal wire (Cam pos) into one of the free pins on the DB37 harness (X11, X12, X13 or X14) and made a jumper wire with a resistor on the end of it, INSIDE the MS case, that connected that pin to CPU pin 11 on the bottom side of the MS PCB board.


On the LEDs, I just followed the Neon Output MOds schematic, sounds like what you are describing here.

-scott

 

[need4speedtsi]

cool thanks.

 

[highbooster]

any updates

 

[babyviper]

sound like your gotta be a freakin genious to hook this thing up. I'm ok as for as wiring stuff but when it comes to resistors and ohms that stuf gets real confusing would the resistors be already hooked up for you if I brought one of those preassembled ones off of diyautotune?

 

[blueman803]

Check the Tech articles here, I made an article detailing the install. I finally got most of my issues worked out in my car and am able to start driving it, so I might be posting up a little more to the MS article.

 

[Lilbloody4]

I'm actually done with my swap, I'm getting fuel but not getting spark at all... I tried the Output test mode, and still nothing, but I did notice that the Power Transistor unit was hot as hell... Can someone try to point me in the right direction...