Megasquirt Support Forum (MSEXTRA)

Hello, I am attempting to add microsquirt v3 to a 700cc briggs and Stratton vanguard 90* V-twin.
We have a set of Gm truck style COP, gm 3 bar Map, gm IAT, gm TPS, 25lb injectors.
We are making a twin spark style pickup with a single magnet and 2 VR sensors on the crank since the cam has no outputs, and there isn’t a easy way to fit a trigger wheel.

I am having a hard time creating/finding a base map for the motor, I have just about all the information for the injectors (jeep pico style) along with all of the information needed for the COP’s, but theres tons of other little settings I'm not familiar with.

Also i still haven’t started wiring so i don’t have power to the microsquirt yet to connect to it and check firmware.

Does anyone have a guide on where to start with creating a base map, or have a base map for a 90* v-twin?

The MS2/Extra setting up manual covers most of the details of making a base map:

http://www.msextra.com/doc/pdf/Megasqui ... Up-3.4.pdf

I had been reading the microsquirt install manual and didn't see that manual. That should clear up a lot of the problems, although it still states start with the preloaded tune in the controller or another sample base map. I was unaware the micro came preloaded with any kind of tune. Trying to track down the “sample” tune now.

*edit: powered up the microsquirt and it loaded in a base map. I should be able to go through and adjust for the sensors and engine specs and get close to starting.

We ordered a dual pickup ignition kit that came with 2 pertronix ignitor pickups, I read the article showing what needs to be done to make them work for a megasquirt setup but im not sure how they would be wired as the 2 pickups for a microsquirt. Could they be wired in like a VR sensor? My understanding is that they are hall effect sensors with a built in processor that turns the signal into a on/off output.

They would be treated as Hall effect sensors that sink current.

Im not sure what you mean by treated as sink current? They are just 2 wire sensors which i believe is just a power and ground so i wasn’t sure how to wire them in as Hall effect.

Matt, I believe you know which project this is going to. Do you think a dual trigger setup with a single tooth is the best way to go with the odd fire v-twin? A missing tooth wheel could be fit to the front of the motor but I'm not sure which way would be a best.

A Pertronix Ignitor actually has three connections. The red wire delivers 12 volt power. The black wire is the output; it switches from floating to ground, so it will need a pull up resistor. The third connection is the ground - which is normally through the backing plate rather than a discrete wire.

A missing tooth wheel is a bit more accurate, but more fabrication.

I was unaware of the casing ground that it had, that clears up a lot. The msextra manual is about 100x more helpful with setup and wiring then the megamanual when it comes to diagrams and clear explanations.

OK so the project is wired up and starting. We had a 8in 36-1 trigger made and used the red hall sensor from DIY. Had a problem with it dying after start till i realized the warm up enrichment table was set to 0%.

We would like to run the motor in sequential so i setup the map sampling and have full sync and it seems to run fine till it gets up to temp and has a secl reset that causes the motor to stumble and die. (before setting up map sampling the motor had a bad miss to it.)

Here is the current tune and the last datalog.

Where is the ECU grounded?

I got it solved yesterday and we had several nice tuning runs using the water brake dyno to hold rpm while working through the rpm range.

The spark plugs that we have always ran where ngk racing plugs which i assumed was the same as a ngk r, looked them up and they weren’t resisted plugs… changed plugs to a ngk r and never had a issue. All grounds are ran to a single bolt on the head.

Do you have any recommendations on a good tuning manual? We are trying to squeeze every ounce of power out of the little v twin. We have only tuned up to 4500 rom currently but im already making 5 more ft/lb of torque over last year with the same exhaust.

For tuning manuals, start with the official MS2/Extra setting up manual.

I'd also recommend this book, but I'm a bit biased.

haven’t updated in a while. ive ran into a wall of sorts trying to get both cylinders to fire at the correct time. its a 90 degree motor with 270 degrees from cylinder 1 to cylinder 2 firing. have 270 set as the odd angle on alternating with wasted spark, but cylinder 1 gets up to temp just fine and the header heats up pretty quick but you can hear a miss in the motor and cylinder 2 header is under 500 deg when cyl 1 starts to glow red. i found a older topic reporting the same problem but there wasn’t a solution.