Assembling Megasquirt
 
The date may say Monday, but it’s 1am right now. Late late late Sunday night. I’m really tired. But I wanted to get a progress report up on the site, in case anyone is reading this. I appologize in advance for typo’s and grammar errors. I’ll try to proof read this in the morning and fix the blatant errors.
Anyways, the above photo shows the scene Saturday morning. I arranged the resistors and capacitors in order by size/resistance. Definitely made finding them easier while assembling the board.
Assembling Megasquirt
Monday, February 26, 2007
I did not buy the optional “Stimulator” to test the board with. I didn’t buy one the last time I built a Megasquirt either, for the same reasons. If you read the assembly instructions, you’ll notice it has you build the MS in distinct sections, and then test each of those sections. By the time you get done, you know the thing will work because nothing has gone wrong along the way. So here is the board with just the 5v voltage regulator section built. I’m testing for voltage per the instructions. 4.94 is perfect, would probably read 5v on a cheaper meter, the Fluke is just very accurate.
The next step was the serial port controller. I tested that by hooking it to my laptop and running a terminal program and seeing if the characters I typed would get looped back to me. They did. After that came building the clock unit, the part that generates the frequency that the CPU runs at. Once that was built I was able to install the CPU and connect to it with Megatune. That worked too.. And so on and so on. Like I said, there’s really no need for the stimulator.
Before I get ahead of myself, I wanted to show the case that the Megasquirt goes into. I opted for the black case. Looks alot nicer, I think. I didn’t put my last Megasquirt into a case (long story). So this is the first time I’ve done that. I was surprised at how small the case is. I don’t think the v3 Megasquirt board is smaller than the old one, but I could be wrong. Anyways, here it is next to my hand for scale.
So here is the board pretty much fully assembled. I still have to add a couple transistors for the radiator fan control, and tachometer output. They’ll go in the “proto area” that little grid on the bottom right. You may have noticed the little blue jumpers wires, and maybe even noticed the big black jumper wires. Those are for the ignition modifications. The blue wire is some seriously thin gauge wire. I went with the thicker black stuff for the ignition outputs, where I was concerned the blue wire was way too thin to do the job. These modifications were the difficult part, the instructions are nowhere near as clear as the Megamanual’s assembly instructions. But I think I managed to do what I needed.
So here is the board slid into that case. Step one of the instructions was to make sure it slid in without binding. It did. A little loose actually, so no problems. And yes, that’s a fly sitting in the case below the board. I noticed that when I was processing the photo’s. It’s a good thing I’m building an ECM and not a teleportation device! hahaha.
This is the top of the board, pretty much done. I think I still had a couple resistors to pick up and install. Had to make a run to Radio Shack to get the correct Bias resistors for the Chrysler intake and coolant temp sensors. As well as a 1.5k ohm 1/2watt resistor for R12, as that’s what the Neon mods page said to use. You can see the extra ignition driver mosfet I installed along the top with the jumper wires running to it. There are no LED’s installed because I’m using those outputs to drive other items. And there are alot of unpopulated spots on the board. Those are optional components that I either chose not to install, or was told not to install by the instructions and or the Neon mods page. The assembly of this unit took me FAR longer than I had expected. Mostly because I was taking my time and being careful. Partly because the instructions for the Neon mods seemed vague and contradictory. All in all, the assembly was uneventful, and I recommend it if you plan to do a Megasquirt, as there are sooo many options along the way, I can’t imagine someone being able to make those choices for you, it’s just flat something you have to do. With that assembled, I moved on to something completely different.
It’s an Arc welder. I’ve never welded anything in my life before today. I wanted to do this last weekend but the goggles I bought were FAR from strong enough. I went ahead and splurged at Harbor Freight and bought the cheapest mask they had. haha, turned out it was the auto dimming model, it was on sale. Very nice. A friend gave me this little arc welder a year or two ago when he was moving out of state. I knew it’d come in handy someday.
I know, it’s a very ugly weld. It took me probably an hour of futzing with the thing before I was able to do anything more than short the rod out and have to yank the glowing thing off the pan, over and over and over. I read some tutorials online last weekend, and I’m glad I did, as I applied the guidance they gave me to my attempts. I did finally get it to start throwing an arc and laying down a bead. Oh, and I’m sorry I didn’t get a “before” picture. I was too excited to play with my new toys. The junkyard punches a hole in
the oil pan to drain them. I guess it’s faster for them. Then they stick a rubber plug in the hole. Funny thing is, there was still a quart or more of oil in the pan when I pulled it down. What’s the point?! Do it right or don’t do it at all. Geeze. Anyways, I pounded the metal back flat before I started, but there was still a quarter inch or more of space that was wide open. I originally only welded the outside. Then I poured water into the pan and it promptly made the outside of the weld wet. So I dried it up and welded the inside. By the time I was done with that I was more confident in my welding “skills”, and touched up the outside some more. Finally I tried the water test again and it seemed water tight. I dried it up and cleaned out the inside of the pan real well. I took this picture just before painting over the welds on both sides to protect them from rusting.
And what do we have here? It’s the balance shaft assembly. Looks exactly like the BS assembly from a 2.5L engine. I didn’t get around to removing it tonight, I didn’t want to fuss with plugging it’s oil feed. I’ll get back to it, that’s for sure.
I remember saying the tire would be really close to the oil filter. He’s what I meant. I can fit my finger tip between the tire and filter. NOT the first joint after the finger tip. It’s THAT close! Get bigger tires, or a bigger filter, and your liable to spin the filter right off the engine in a turn. Ooopsie!
While I was down there, I went ahead and took a picture of the crank pulley. I read that the Neon guys HAVE to run an underdrive pulley (smaller) to clear the frame of the car. Heh, glad I don’t have to. Don’t want to buy one, and I like my voltage staying up at idle. As you can see, I went with a 5 groove belt. The guy at the parts store was being a bonehead and couldn’t seem to find me a 1meter long 6 groove belt. “But the computer says your car needs this part number” ... and I told you, I’m not running the AC compressor, it’ll have to be shorter. “The computer doesn’t show it without AC” Some times I just want to smack people upside the head. But they don’t call it Autostoned for no reason. Oh, and I believe I have enough room down there to install the AC compressor later on if I want to. But I probably won’t since this car never had AC and it’s no small task to fix that.
Now that the pan is fixed, and I have an oil filter, I was finally able to add oil to the engine. I still don’t have a valve cover gasket, so it’s not bolted on, but I wanted to do a couple revolutions of the engine with the starter. So I re-installed the engine bay harness that I had mutilated a couple weeks ago. Then I made another movie. (Keep in mind, I was VERY tired when I shot it, in fact, I’m beyond tired now, since that was about 4 hours ago.. It’s alot of work to do this blog) Enjoy the movie.