Weber 750 & Megasquirt ECU

[Friendly]

While Tony is building an Electronic Unit for the NA Weber motor, I am looking for a replacement for the Polaris Unit on my Turbo 750.
I have elected to try a scratch built Megasquirt II Version 3 board ECU.

Tony is using a Microsquirt, Mine is the Megasquirt.
If you go to the web link, you can read as much as you would like about the two ECU's. The primary difference in our two applications is I am going to use the IAC stepper motor which the Microsquirt does not readily use.

I am going to keep the Megasquirt build on this tread so people will not confuse the two processors.

I would like to thank John (All In)who graciously offered to assemble this unit for me, but I did not think I could answer all of the option questions for John as he would build this ECU. So I will try it myself.

http://www.megasquirt.info/

It normally takes 8 to 12 hours to assemble the unit. If you know what your are doing it would be similar to painting by numbers. I hope I can do this and put it here where it may help someone else.

Corrective Criticism is welcome.

[WHY]

Thanks for the post Mark. Your quite right about the IAC, yours can be a stepper but the Microsquirt can only run either a pwm F-idle valve like Ford uses or a fast idle solenoid cam on the throttle shaft or as I have decided to do and that is go total manual on fast idle (open the throttle a little at the start) and let the ECU supply the rich fuel mixture until the engine warms up. Will have a few pics in a day or two on the ECU and fuse block mounting.

Tony

[HobbyCAD]

I like these Mega and Microsquirt ECU's. Only problem for me, they bankfire the injectors, so one can only use it for even amount cylinders. What product is out there to build a custom ECU for my 3-cyl Yamaha?

[Friendly]

Originally Posted by HobbyCAD

I like these Mega and Microsquirt ECU's. Only problem for me, they bankfire the injectors, so one can only use it for even amount cylinders. What product is out there to build a custom ECU for my 3-cyl Yamaha?

As Tony as stated, the Sequential board will allow COP ignition and injection firing on up to 8 cylinders.

Heres the link
http://www.megasquirt.info/

[WHY]

Francois

Go to the Megasquirt introduction page, they state that the Megasquirt will also operate 3 and 5 cylinder engines by sequential firing of injectors and coils .

Tony

[WHY]

Hi Mark

Finally found the answer to my last question on my Walbro/Weber set up. The sensor that bolts to the intake manifold is BOTH the MAP and IAT, thought it was AIT only until I got suspicious about the 4 pins in the connector, found a drawing and some specs on a parts site and they stated it was both. So--- have started wiring the set up.

Tony

[All_In]

I was looking forward to this project, but understand why you would wish to build it.

Very exciting!!

[panda_nzzz]

I built my Mega squirt ECU. Very easy to build and great instructions.
You really do need a wide band O2 set up to fully tune it. I got one and it takes all the guess work out of it.
Roy

[Friendly]

Originally Posted by panda_nzzz

I built my Mega squirt ECU. Very easy to build and great instructions.
You really do need a wide band O2 set up to fully tune it. I got one and it takes all the guess work out of it.
Roy

Roy,
I hope you will contribute to the thread, I am wading through this. Now I have to remember where I put the Weber Manuel.

For anyone following this thread,
The Megasquirt is assembled in 5 stages.

1 Power Supply Construction and Testing (steps 1-23)
2 Serial Communications Construction and Testing (steps 24-26)
3 Clock Circuit Construction and Testing (steps 27-41)
4 Input Section Construction and Testing (steps 42-55)
5 Output Section Construction and Testing (steps 56-80)

Average time to build is 8 to 12 hours. I will only be working a few hours in the evening so it will take longer for me.

Here is the Canvas for our solder by numbers.

[panda_nzzz]

I will help if I can
I think if I was going to do another one I would consider removing the connector for the wiring. If any electrical part is likely to fail it will be at the connector. It does make it a pain if you need to remove it but may be worth the effort if it stops an engine out.
Roy

[Friendly]

Originally Posted by All_In

I was looking forward to this project, but understand why you would wish to build it.

Very exciting!!

John,
I may still need you to build this, but to be honest with you, after reading through the assembly Manuel, I realized that you were going to be asking me lots of information to build it for the Weber, that I did not think I could give you a good answer, because without building the board, I wouldn't be able to comprehend what you would be asking.
Like should the ignition output be ignition out, or ignition out inverted? ,VR,,Halls, Optical, High Gain Circuit, 5 volt, 12 volt , coils , coils with modules, COPs , on and on. The Megasquirt is so versatile, it can be set up for most any motor, but you must understand where to jumper the connections.
I believe I can figure it out, but I am a very visual type learner.

1 Megasquirt arrived in small box, see comparison of the sizzors

2 The parts nicely packaged with part numbers as well as step numbers such
R1, R2 , R17 may all be the same resistor, so they will all be in the same bag and you just assemble them like painting by numbers

[Friendly]

I bet you are talking about the 37 pin DB connector that I soldered in already!
I purchased a stimulator with the kit so I can test the components as I build this thing. It plugs into the DB37 connector. I will have to leave it in place. I would rather trace a problem to something I just put in, instead of the whole board.

[WHY]

Hi Mark

Well this morning about 2 a.m. I woke up and realized I had made a wrong connection on the fuse block (really 2 a.m. ) . So this afternoon I went out to the hangar and corrected the connection right away and the rest of the day was just one screw up after another. If I didn't screw up at least once or twice, I got worried about what I had missed something. At the end of the day about 8 pm I had made a "little" progress so it was not a total loss.

Tony

Tony

[Friendly]

Originally Posted by WHY

Hi Mark

Well this morning about 2 a.m. I woke up and realized I had made a wrong connection on the fuse block (really 2 a.m. ) . So this afternoon I went out to the hangar and corrected the connection right away and the rest of the day was just one screw up after another. If I didn't screw up at least once or twice, I got worried about what I had missed something. At the end of the day about 8 pm I had made a "little" progress so it was not a total loss.

Tony

Tony

Sorry to hear you had a ruff day. I did not see you post until this afternoon. In our work, we have to train sweep a house., no one likes to be the man on point because he is first to get shot. lol, the rest of the team learns from him getting shot where the enemy is and then we shoot the enemy.
We tell our point man what a good job he did but he is still not real happy about it.
You going on point with the wiring harness makes me laugh a little and say, I hope he finds all those bugs before I get to them. lol
Keep me posted so I can learn.

[Friendly]

I just followed the numbers and added components. Double check for polarity and the power supply went well. The ECU is not soldered in. It has a socket so it can be replaced and makes for easy testing of the circuits.

1 Adding components
2 40 pin scocket
3 Bottom of PCB
4 Finished Power Supply, 23 steps and ready for testing