Another project - MegaSquirting

sabretooth · Postby **sabretooth** » Sun Feb 03, 2008 3:52 am

I've interrupted my interior swap project to embark on another project - one which I've been unsure about, but have been pondering for quite a while now. The work-in-progress was to replace my aging Haltech E6A ECU with a MegaSquirt.

It was actually a bit of a project of opportunity - I was building a MegaSquirt for a friend, but the car on which it was to be installed was sold, leaving the project just sitting around gathering dust. Recently, I saw how well DIYAutoTune's MegaSquirt PNP worked in zoomzoom and saboteur's cars - and figured that rather than pay $900, I'll finish the project and slap it into my car instead - and instead pay $300.

For now I'm just going to write about what I've done - all of the \"how to\", \"what is\" and \"where do I start\" stuff will come at a later date. The whole MegaSquirt thing is a bit overwhelming - I found it hard to know where to start, and where to go after I'd finished building the unit. What I'm going to try and do is include a summary of what you need to read, what you need to do and how you need to go about things, in a bit of a structured manner.

The versions can be a bit confusing, but what I've got is a kit from DIYAutoTune - it's the MegaSquirt 1, built on a V3.0 PCB. I finally finished the assembly today, and this is what it looks like:

It's had a few mods done to it - PWM idle control, ignition output modifications, etc.

I actually intend to fit the MegaSquirt inside the original MX-5 ECU's case. Aside from the DB9 socket and map sensor tube, it should look completely stock. Here's a bit of a mock fit taken not long ago while I was still assembling the PCB:

To make the PCB fit, I'm going to have to remove the end connectors and put vertical ones there instead, and possibly grind some of the inside of the case. Making the PCB fit will come later on - for now I just want to make sure that the thing works! The MegaSquirt's case is nice and all, but I'm going for a bit of a factory look. And, to be honest - it's hard to beat the authenticity of an actual case.

What I have to do now is update the firmware etc on the chip, build the MegaSquirt->MX-5 ECU adaptor loom and then do a test fit. So far things seem to be testing OK with saboteur's MegaStim, so I can't see why it wouldn't function in a car. Both figuring out and doing the wiring is going to be the next time-consuming task - but hopefully not too difficult.

The other recent purchase has been an Innovate LC-1 - also from DIYAutoTune. That will be used to help tune the car once the ECU's up and going.

Postby **Okibi** » Sun Feb 03, 2008 9:57 am

Geoff does your NA8 have the 1.6 plug or the 1.8 plug on the ECU?

sabretooth · Postby **sabretooth** » Sun Feb 03, 2008 11:23 am

The plugs are the same. I believe just the wiring is different. I've tested my car's loom in the ECU I bought from Richard, and it fit perfectly.

Postby **Okibi** » Sun Feb 03, 2008 4:26 pm

I thought the 1.8 ECU had a different plug (EXCEPT the VERY EARLY 1.8s - and yours is a 94) ?

sabretooth · Postby **sabretooth** » Sun Feb 03, 2008 4:56 pm

Dunno, all I can tell you us that I've got a 94, and this is an ECU from an NA6. And it fits.

ampz · Postby **ampz** » Mon Feb 04, 2008 9:52 pm

Nice.

Add EBC and fans mod with the kits from DIY.

Adjust the settings as per this link.

The base map from the MSPNP will get you close, the lc-1 with autotune will get you closer.

The MS does things a little differently from the norm but works well once understood.

Cheers
Nuno

sabretooth · Postby **sabretooth** » Tue Feb 05, 2008 11:53 pm

The MiataTurbo link was essentially useless as far as wiring diagrams though. I'm slowly piecing together wiring diagrams and the like. You've gone the parallel route haven't you? I think I'm about to embark on a painstaking wiring-diagram-matchup process.

ampz · Postby **ampz** » Sun Feb 10, 2008 11:01 pm

Yeah parallel.

In my case the mazda ecu is controlling idle and aircon. But as soon as I have an aircon circuit designed, I will be going standalone.

With your 94 you should be able to use the variable tps with closed loop idle control to adjust while the air is on.

Next tinme you are at a wreckers, check out 87-94 corollas, they have a separate box which controls the air. If you get one cheap enough use it to reverse engineer a circuit for your air control.

sabretooth · Postby **sabretooth** » Thu Feb 14, 2008 10:46 am

I'll have to experiment with just grounding that wire and ungrounding it and seeing how it affects the operation of the rest of the system. From there I'll see if I can rig up something on the prototype area to control the AC.

I've nearly finished the MS->MX-5 harness! There's not really any reason I can't test it now.

sabretooth · Postby **sabretooth** » Fri Feb 15, 2008 12:58 am

Well, I hooked it up tonight, and for the most part it seems to work! I didn't hook up the coils, but things were looking positive. The only unexpected thing was that the TPS reading wasn't changing at all. The expected \"not working\"s were the air temp - it's wired in separately for the Haltech, and I haven't yet added the necessary bits. I just have to make a plug up that will adapt the GM air temp sensor to use the air temp sensor wires in the MX-5 loom.

But, the coolant temp, RPM (when cranking) and O2 readings seemed to be working!

This weekend I'll finish up the wiring so that I can get the car running from the squirt.

sabretooth · Postby **sabretooth** » Mon Feb 18, 2008 11:22 am

My weekend was a pretty trying one - saboteur came around and we started going through stuff trying ti figure out why sensors weren't working or were giving dodgy readings. It took us a while but eventually figured out that the miataturbo.net's faq diagrams are useless if you want to do a standalone installation. They purport themselves as a \"this is all you need\" solution, but that's not the case!

I started Saturday at MX-5 Plus, and bought a set of factory 1.8L coils. Originally, my Haltech killed two sets of 1.8L coils which led to me reverting to the ignition setup from the NA6s. I figured - may as well do this right! So I started pulling stuff out - the 1.6L ignitor, the 1.6L coils, the Haltech itself, the Haltech harness, the Jaycar voltage switch...

Then I did work on the car's harness. I assume a previous owner was using an interceptor ECU for a while (URGH), as the CKP and CMP lines from the CAS had bullet connectors in them. I removed those, soldered in some similarly-coloured wire and neatened it up. I cleaned up any other wires which were broken/dodgy, and gave it all a general tidyup.

saboteur arrived again on Sunday, and we started sussing out the situation with the sensors. Fortunately the Haltech and Megasquirt both use GM air temp sensors, so it didn't require changing. Many wires going to the sensors themselves were borderline - so borderline that I broke two of them. We ended up redoing the wires going to the connectors for both the water temp sensor and the air temp sensor. Fortunately saboteur showed me how to pull the air temp sensor plug apart without having to butcher it.

So after about 3hrs of hard work, we both managed to figure out the grounding issue with the coolant temp sensor - and make the TPS work. That was pretty much everything - we calibrated the throttle, set the req fuel settings, and finally started the car. And... it ran! It was stumbling like mad, but it was running with a bit of throttle assist!

I remembered some settings I had set on the Haltech, and so changed the trigger angle accordingly. saboteur fiddled with the fuelling, and we managed to get it to idle very nicely.

So that's where we are so far!. Today I'm calibrating and hooking up the wideband, setting up the idle and maybe going for a little drive!

ampz · Postby **ampz** » Mon Feb 18, 2008 2:29 pm

It is a neat little package. Are you planning on EBC (electronic Boost Control)? I didn't see it on the board

Edit: Your board will fit a lot easier if you remove the DB (and replace it with a Cat 5 Jack (trust me on this one). I have one and made it to resemble the pinouts of a cisco router. That way i only need to use the light blue console cables (it saves a bit of space too as with both DB connectors on the unit is too long to fit nicely in the footwell).

Fatty · Postby **Fatty** » Mon Feb 18, 2008 5:21 pm

excellent work , well done!

sabretooth · Postby **sabretooth** » Mon Feb 18, 2008 5:35 pm

I will do, but not just yet. I've got to do the mods for EBC and a few other things yet. Nice call with the plug - I'm actually considering using something different also.

The DB37 will be replaced with a vertical connector, and the DB9's fate is still to be determined. To serve the same function as the MSPNP, I've rigged up a DB15 to use as a feature connector. Right now it's just got the LC-1 hooked up to it, but it soon will have launch control and any other goodies I can think of.

As it stands - the air temp line has been repaired, threaded through conduit, and hooked up. The Innovate LC-1 has been calibrated and hooked up through the D15, and the MAP sensor has been hooked up without the aid of electrical tape. :p

I just have to get it running and out of the driveway for some easy tuning next!