For anyone who’s interested, here’s a brief description of my setup.
When I started all of this, Megasquirt was fuel only. I very seriously considered using SDS, as they have an excellent product with probably the best support in the industry, but I needed custom features that they couldn’t provide, and modifying their firmware is not an option.
Megasquirt was, and still is, to a degree, open source. I have no formal training in electronics or computer programming so I had to teach myself what I know. MS1 firmware is written in Motorola assembler. MS2, and the later variants are written in “C” or a combination of “C” and assembler. I do not speak “C” but have become relatively comfortable in assembler, so I stick to the MS1 hardware and base my code on it. I was able to use the megasquirtnspark code to develop my own version for TFI ignition control. Something similar is available in the MSnS Extra code.
I have modified the MS1 V2.2 board with a daughter board to accommodate a second MAP sensor for continuous barometric correction. I also have another A/D input for on the fly fuel or ignition trim and pulse inputs for vehicle speed and ignition diagnostic monitor. There is a permissive input from the transmission controller for decel fuel cut, and (on the motorhome) exhaust brake control. Fuel and ignition tables are now 12x12 as opposed to 8x8 for the original MS1.
I wrote assembler code for “Megaview” to use it as a “digital dashboard” so I can monitor just about all the variables real time without having to connect a lap top. I’ve modified Phil Tobin’s “Tuner Studio” to tune everything with. I had originally modified “Megatune” but TS is much more flexible and powerful.
The transmission controller is my own design, and really the reason why I got into programmable EFI in the first place. I got so frustrated with the shift scheduling and TCC control with the E4OD in my motorhome that I looked for an aftermarket controller. At the time, I talked with Karl Baumann about his unit, but I needed some features that it didn’t have so decided to build my own. The MS GPIO transmission controller wasn’t out at that time, but it may be able to control the E4OD now. My first design used a “Basic Stamp” and some math co-processors, programmed in Q basic. It worked well enough, but after getting into MS, I built a second generation one based on the MS design, and code knowledge I’d gained from it.
The controller is what I call “semi-automatic”. Lever positions in P,R,N, and L work as OEM. In Drive, progressive gear shifting is controlled by a 4 way joy stick. Pulse back, shift up, pulse forward, shift down. TCC control is on the same stick. Pulse left, TCC lock, pulse right, TCC unlock.
TCC control is subject to permissives for being in a gear that will support engine braking, engine revs above 1200 RPM and closed throttle position.
I wasn’t able to develop a successful code for line pressure control, so I use an external commercial hydraulic variable force solenoid controller that I just send a 0-5v signal to. I have separate tables for steady state pressure, 1-2, 2-3, 3-4 shifts, TCC lock, and decel pressures. I ran out of outputs on my engine controller so I use the transmission controller for manual idle speed control on the engine, sort of like a hand throttle. I was able to modify “Megatune” to tune it with the laptop.
It’s all quite specialized, but if anyone is serious about doing something similar, I’d be happy to provide any help that I can.
When I started all of this, Megasquirt was fuel only. I very seriously considered using SDS, as they have an excellent product with probably the best support in the industry, but I needed custom features that they couldn’t provide, and modifying their firmware is not an option.
Megasquirt was, and still is, to a degree, open source. I have no formal training in electronics or computer programming so I had to teach myself what I know. MS1 firmware is written in Motorola assembler. MS2, and the later variants are written in “C” or a combination of “C” and assembler. I do not speak “C” but have become relatively comfortable in assembler, so I stick to the MS1 hardware and base my code on it. I was able to use the megasquirtnspark code to develop my own version for TFI ignition control. Something similar is available in the MSnS Extra code.
I have modified the MS1 V2.2 board with a daughter board to accommodate a second MAP sensor for continuous barometric correction. I also have another A/D input for on the fly fuel or ignition trim and pulse inputs for vehicle speed and ignition diagnostic monitor. There is a permissive input from the transmission controller for decel fuel cut, and (on the motorhome) exhaust brake control. Fuel and ignition tables are now 12x12 as opposed to 8x8 for the original MS1.
I wrote assembler code for “Megaview” to use it as a “digital dashboard” so I can monitor just about all the variables real time without having to connect a lap top. I’ve modified Phil Tobin’s “Tuner Studio” to tune everything with. I had originally modified “Megatune” but TS is much more flexible and powerful.
The transmission controller is my own design, and really the reason why I got into programmable EFI in the first place. I got so frustrated with the shift scheduling and TCC control with the E4OD in my motorhome that I looked for an aftermarket controller. At the time, I talked with Karl Baumann about his unit, but I needed some features that it didn’t have so decided to build my own. The MS GPIO transmission controller wasn’t out at that time, but it may be able to control the E4OD now. My first design used a “Basic Stamp” and some math co-processors, programmed in Q basic. It worked well enough, but after getting into MS, I built a second generation one based on the MS design, and code knowledge I’d gained from it.
The controller is what I call “semi-automatic”. Lever positions in P,R,N, and L work as OEM. In Drive, progressive gear shifting is controlled by a 4 way joy stick. Pulse back, shift up, pulse forward, shift down. TCC control is on the same stick. Pulse left, TCC lock, pulse right, TCC unlock.
TCC control is subject to permissives for being in a gear that will support engine braking, engine revs above 1200 RPM and closed throttle position.
I wasn’t able to develop a successful code for line pressure control, so I use an external commercial hydraulic variable force solenoid controller that I just send a 0-5v signal to. I have separate tables for steady state pressure, 1-2, 2-3, 3-4 shifts, TCC lock, and decel pressures. I ran out of outputs on my engine controller so I use the transmission controller for manual idle speed control on the engine, sort of like a hand throttle. I was able to modify “Megatune” to tune it with the laptop.
It’s all quite specialized, but if anyone is serious about doing something similar, I’d be happy to provide any help that I can.
