UPDATE: As of Apr. 26th 2014, this writeup now covers MS1 - MS3 and MS3-Pro. See this thread for more information: https://www.rx7club.com/megasquirt-f.../#post11725764


Hey everyone,

I just finished updating my website and one of the major parts of it was a step by step Megasquirt tutorial on the 2nd gen RX-7.

When I say "step by step", I mean a complete writeup that covers the entire process from starting with a bone stock car, to wiring in the Megasquirt, programming it in Megatune and even some basic tuning instruction. It was a huge undertaking, much more so then I originally thought and took nearly 8 months to complete. In my opinion (though I am biased) it may be the single greatest Megasquirt writeup outside of the Megamanual and MSExtra sites.

You'll find it here:
http://www.aaroncake.net/rx-7/megasquirt/

The writeup covers both MS1 and MS2, but I do have one warning. As I do not have an MS2 to play with, I based my MS2 programming info on some old maps I have for the few cars running MS2 I have played with. If you notice anything wrong, please let me know and I will correct it ASAP. Also, different people have different ideas of how things should be done, so if you have any suggestions, I'd welcome them.

 

Wow 8 months. Now everyone should know why I have not done something similar! If I took the time to do this I wouldn't have time to work on ms3 and ms2/extra.

I skimmed the document, and to me it looks great. Some things were done differently from how I normally do them, but everything there will work fine.

The main thing I do different is that I use the daughtercard I designed for the lm1815 circuit and the idle valve circuit.

Anyway, I'm making this a sticky.

Ken

 

This is the reason I need to refresh more often. Wow great read just awesome

 

Very nice detailed write up, Good Job.

 

Very nice, I like the detail all the way through. I especially like the fuse/distribution block I'll definitely be looking for something similar to that when I finish up my other car. The only thing I really didn't like was the setup at the battery. I would've tried to use a free spot in the existing fuse panel (ABS if avail,etc).

 

I had no idea such a thing even existed. DIYAutoTune emailed me with a link to the daughtercard and I intend to use it for my next build (a V3.57 MSII for my '76 Cosmo). After which I will update the writeup with the daughtercard and V3.57 info.

Cool. I didn't stick it myself since that would seem rather presumptuous.

I have never even considered using the stock fuse block, but if there is an open spot, I see no reason to not use it. One thing to make sure of is that the alternator and battery wire to the block are in good shape since you will be adding about a 30-40A draw (when the e-fan is on) to the system.

 

I used to try to do that a lot when possible to keep wiring cleaner and keep as many random blocks/breakers/fuses all over the place. I usually use the ABS (if not equipped) for the EFAN on S5 cars and just use the original EGI fuse for the rest. Makes it nice and easy to troubleshoot too! Though i've had to usually put in a 100 main on the S4's.

I'm about to setup a pretty virgin 2.2 MS1 (probably upgrade to MSII at the same time) if you want I'll get some pictures of the board/pullup's and mod's needed to get the 2.2 board setup so you'll have all of the boards available on the write-up. I'll be using the Zeal daughter for the VR's and using the output circuits as well.

 

I'm not sure if I am going to extend the writeup to the 2.2 since it is obsolete.

 

This writeup is an answer to my prayers. There are a lot of holes in my understanding of the specifics of Megasquirt, and this writeup is exactly what I needed.

I can't thank you enough.

 

In perfect timing too. I am about to purchase MS in the next day or so, I have been dreaming about Squirtin' a car for a long time. Thank you!!!

 

Be sure to let me know if there are any holes in the writeup, because it sounds like you are going to go through it start to finish. Sometimes it is easy to overlook something because it seems "obvious"....But it's only obvious if you've lost count of the number of Megasquirts you've installed.

 

Yes, I'm going to be pretty thorough. I'm putting a 13B-RE in a previously-carb'd FB, so I'm making the ECU system from scratch. The wiring harness from the donor motor was cut at the bellhousing, so I've got a lot of wiring in my future.

 

Great job, especially the programming the MS2 section. Even though I am past basic startup that section caught a couple of areas where I can get some immediate improvement. I will be making those corrections tonight or tomorrow. Will have my first real chance at some tuning runs on Thursday during some slack time at the track where I am working with a Kit Car Club running timing. That is if it isn't pouring down rain which is in the forecast.

 

hey aaron I think I can help you out with the s5 injector connectors check out this site i believe they have them http://kgparts.com/index.php?page=kgfuel part number ND-IC this should help out a few people hopefully

 

Excellent. I will update the writeup soon.

Also I need to change a few of the DigiKey part numbers. They are correct, but some of the parts (the.33uF tantalum capacitor) come in cases that most people are unfamiliar with.

 

ok im ready to build my ms2 v3 i am going to use the zeal daughtercard this will eliminate needing to build the second vr circut and the PWM bac mod correct? do i still need the ignition output pullup resistors?

 

what of theese steps does the zeal daughtercard eliminate?

* Do not install the jumper mentioned in step 22 and ignore that step entirely.
* As step 50 suggests, install both the hall/coil/optical trigger circuit and the VR trigger circuit in step 51. Follow step 50-b when building the hall/coil/optical circuit so that you can use the Stimulator. We will ultimately only use the VR circuit when the 'Squirt is in the car.
* In step 52, follow the instructions in the blue box to the right to configure the 'Squirt to accept an RPM signal from a coil/points/optical. This is so the Stimulator will still work.
* In step 54, use the stock values for R4 and R7 because we are using the GM IAT and CLT sensors.
* In step 59, to not install D8.
* In step 62, follow the instructions in the blue box titled "PWM Idle Valve Users Only" to install the PWM idle valve mod. This step instructs you to install a TIP120 (or equivalent) in place of Q4.
* Skip the installation of Q20 in step 74.
* In step 75, install a jumper instead of R39
* While you don't need to, you might as well install the high current ignition driver in step 65. In 65-d, don't bother installing any jumpers. Ignore the note about adding a pullup resistor.
* In step 69, install the PWM flyback circuit. Then follow the instructions in step 70 to install the standard flyback circuit. Install the clamping circuit in step 71.

 

It can replace the steps having to do with buidling the second trigger circuit in the proto area, and the steps for building the PWM idle valve control.

You still have to wire the board to the same places you would've wired those circuits though.

Ken

 

I have a question about the bit in your write up about the BAC...

So what if you want to run ITBs or a custom intake manifold, can the megasquirt not run it? Or is it, that since the BAC is already there, its easiest to just use it?

 

There is no issue running any sort of manifold on the Megasquirt.

Running the BAC on ITBs will require some thought. You'd have to make a small BAC manifold with a tube to a nipple on each runner, then feed the BAC with air from the filter.

With a custom manifold, just build in a flange for the BAC.

As I mentioned in another thread, the reason I included the BAC in the writeup is to allow the ECU to control the idle. Removing it would be DOWNGRADING the car compared to what the stock ECU does, and a standalone install should always be an UPGRADE.

To this day, I have no idea why people don't want BAC valves on their car. It baffles me. I don't have one on my car and I am so desperate for one that I am sending my Microtech back to Oz at considerable expense to have the BAC upgrade installed, and then modifying my custom manifold to accept one. Cars that don't idle suck.

 

UPDATE: There is a mistake in my writeup for MS2/Extra 2.x!!

The settings on the programming page for MS2 are correct for 1.x firmware, but not 2.x firmware! If you use them, you will have weird timing.

Instead, use the settings found here: http://www.diyautotune.com/tech_arti...zda_fc_rx7.htm

Copied and pasted below (hopefully DIY won't mind):

-Spark mode: Toothed Wheel
-Trigger angle: 0
-Ignition input capture; Rising Edge
-Spark Output: Going Low (Normal)
-Number of coils: Wasted Spark
-Spark A Output Pin: D14
-Dwell type: Standard Dwell
-Maximum dwell duration: 3.0
-Trigger wheel arrangement: Dual wheel
-Trigger wheel teeth: 24
-Tooth #1 angle: 0
-Wheel speed: Cam wheel
-Second trigger active on: Rising Edge
-And every rotation of: Crank
-Enable rotary mode: Rotary on
-Output mode: FC mode
-RX8 mode: Disabled

I will correct my writeup soon. I don't have an MS2 to play with.

Additionally, my VE table for MS1 has a weird RPM spread. I have no idea how this happened. If you use my table, change it to have a bin every 500RPM until 4500 RPM, then every 1000 RPM (or whatever fits). I don't know how the table ended up with bins at 2800 and 3600 RPM, but I will fix this soon.

 

Tooth number 1 angle for a stock-stabbed CAS should actually be 5 degrees. I'm not sure why DIY has it at 0. It won't hurt anything but you'll have to move the CAS a little from stock.

Ken

 

Extremely well thought out and executed writeup. This should dramatically reduce confusion and build confidence in persons with unfinished 'squirts as well as potential buyers looking for an affordable high-quality feature-rich standalone. Nicely done.

 

Thank you!

I should mention that a few weeks ago I corrected the VE and timing tables.

 

stupid question, when talking about the accelerator pump, do you mean the acceleration enrichment setting under the accel wizard?