If you chose to go the do it yourself route you will have to do quite a bit of reading and learning
before
you even buy a DIY kit if you haven't built one before. If you really
don't like to or don't have the skill to solder small parts on a
circuit board then you might want to enlist the help of a friend etc to
build the kit for you. It you are building your first ECU expect to
take several days of building and testing of the unit to check your
workmanship.
I chose to use
the Megasquirt ECU. The Megasquirt DIY
kit has been on the market for many years now and has an established
reputation.
http://www.diyautotune.com/index.html
The stock number of the unit I bought is MS230-K. I also bought a
"stimulator" kit (MSStim22-K) at the same time. For those of you who
would rather
not assemble your own unit they also have assembled units, bare PCBs,
and various other parts to build/modify the ECUs etc. Again, I don't work for this company either. (I'm retired.)
If you are interested in the Megasquirt kit, I would strongly
suggest that you go to their website and try to absorb as much
information as you can. As they say on the site, this whole process is
also meant to be a learning experience.
http://www.diyautotune.com/support.htm
The Megasquirt website has the manuals for all the ECU kits they offer
and are required reading to learn what, why and how the
units work. Go to the forums and read the questions/answers
that other people have posted.
There is so much to learn that it will
take some time to get enough information to even figure out what
questions to ask. I spent several -months- reading and downloading
articles etc so I could understand what and how the ECU works and
what options are available.
The old saying, "The more you know, the
more you know
that you don't know enough." applies here. The owners of
diyautotune and the software authors are extremely knowledgeable and
are very willing to share
their knowledge.
The build instructions are on line for downloading. If you are familiar
with electronics you will find that the instructions are complete
although they might be cryptic for a beginner. If you understand how to
read electrical schematics you will find them on the site also. If you
have built an
electronic kit(s) before you shouldn't have much trouble putting the
ECU together.
I would highly recommend that you also buy one of the "stimulator" kits
when you
place your ECU order. A stimulator by any other name would be a simulator.
This piece of test instrument simulates the signals that you would get
from the sensors on your engine. If you buy a stimulator, build it
first as you need it to test the
ECU as you assembled it. You build one circuit at a time on the ECU
board and then test it. If you find a problem as
you go you know exactly which circuit has the problem vs building the
whole ECU and then trying to figure out which circuit is not working
correctly.
I
could have easily built a stimulator from the schematics and using
parts I already have. but I decided
that it would be
time better spent building the ECU itself. And if you aren't that good
at soldering, building the simple simulator will be good practice.
The stimulator I bought only supplies the crank sensor signal to the
ECU. My engine has an 8 tooth crank "wheel" and a camshaft sensor
signal that is required by
the ECU. I designed a simple divide by 16 circuit to simulate the
camshaft
signal using a MC14040 IC and a few other common electronic parts. (16 teeth of the crank wheel pass by the crank sensor to one
pulse from the cam sensor.) My divider is powered by the simulator.
There is a newer stimulator
that has circuitry to simulate various common car engines timing
"wheels".
I'm not sure if it also provides a cam signal or not.
Near the end of building the ECU you have to load the firmware into the
micro-processor on the ECU board. You use a COM port on your computer
to do this. There are several current versions of the free firmware
available. The basic version is very complete and can control both the
fuel and ignition of your engine. There is another version of the
firmware called "Extra" that has even more options that you can use.
There are also two different (free) tuning programs on the site that
you
use
to set the ECU up for your engine. Only one program is required and
they are both quite similar to each other. But at least you have a
choice to see
which one you like best.
Just getting the engine to start is
going to be your first big test. And by using the simulator and using
one of the tuning programs to set up the ECU with your engine
parameters
you will
have a pretty good chance that the engine will start and run. The idea
is to eliminate as many variables as
possible before you install the ECU into the car/motorcycle etc.
Considering that you have to modify the injector and/or ignition wiring
of the vehicle, it's best to have all the settings that the Megasquirt
is capable of already set up and the proper jumpers installed etc.
OK, let's take a look at the kits themselves.
To see an
enlarged view of most pictures, left click on a picture or right click
and select "View Image".
