1985/1986 1200 GW CFI ECU Upgrade - PnP ECU

I mentioned this in my thread: https://classicgoldwings.com/thread...d-1986-se-i-fuel-injection-motorcycles.14941/

The Speeduino Project ECUs are used for PnP applications because of the open source concept, lots of interesting developments being done with regards to PnP ECU designs. This is not to say that a different aftermarket ECU provider would not do the trick; however, I like the Speeduino Project and will use it for the basis of this thread. As with any of my threads that are based on a premise, this thread is for information and maybe the impetus that helps a person decide whether to upgrade/modernize the '85/'86 1200 GW CFI ECU.

I have started my research into what is a PnP ECU is, what it comes with, and what the user will have to do to use it. I will be using the Spark Gap X4 from openlogicefi as the design prototype for this project discussion, I'm using this ECU for the CFI system upgrade/modernization project. This Speeduino ECU clone has all the attributes required for a PnP CFI ECU, IMHO. There are others that can be used, but that is for the next PnP CFI ECU designer to do.

Short preamble. Cheers

Mentioned that I would be using the Spark Gap X4 as the basis for this PnP ECU. Have to look at the configuration of the existing board, extremely small and would need to have the board modified to fit the original CFI ECU case. This is a good thing in that there would be lots of room for additional circuits, one that I can think of is to design a circuit that emulates the CFI diagnostics. Not out of the realm of possibilities, but would take some thought and programming to include.

Most of the aftermarket Speeduino ECUs have connections for a Bluetooth module that allows connectivity between a tablet/laptop or cell phone for monitoring the EFI system. A small footprint like the Spark Gap X4 has very little room to install a Bluetooth adaptor in the case. Having an area such as that of the CFI ECU enclosure/case is beneficial in this instance.

The connector would have to be changed from an IDC 40 pin to a 35 pin connector similar to what is used in the original CFI ECU, IDC 40 pin connector on the left, 35 pin connector on the right:

It's a configuration issue. You would need to use the CFI system wiring harness pinout then add additional connections for ignition, fuel injection and the likes.

A USB connection would need to be installed. Preferably a USB 2 connection, works well.

The PnP ECU would have the MAP sensor on the interface board, as well as the barometric sensor. Original CFI PB (MAP) sensors would no longer be needed. With the PB sensors made redundant, this frees up 2 circuits that can be used for crank and crankshaft Hall Effect sensors in lieu of the original CFI VR sensors. Using Hall effect sensors eliminates the need for a VR signal conditioning module to be installed on the PnP ECU interface board. The ECU requires some components to have a digital square wave signal. The VR sensors input a sinusoidal wave signal that needs to be converted into a digital square wave signal, ergo, the need for a VR signal conditioning module.

You may read about a "stepper" motor. This is an ECU controlled air actuating valve to admit air into the engine at start, idle when the throttle plates are closed, and during periods of deceleration. The control of the stepper motor is done with a "stepper" motor control module that is added to the PnP ECU interface board. The 1200 GW CFI system has a passive that does exactly the same thing, and is always in operation when the engine is operating, and as such there is no requirement for a "stepper" motor control module. The new PnP ECU would have the "stepper" valve module header installed just in case a person would like to install an ECU controlled air system, but why would you.

You may wonder if the additional air from the passive air system affects the engine air-fuel mixture and the answer is yes; however, you compensate for this additional air when you calibrate the VE fuel) table.

The schematic for the Spark Gap X4 ECU is attached, PDF file so it should be readable. The Spark Gap X4 schematic can be viewed at this location: https://github.com/OpenLogicEFI/Har...anagment/Spark Gap/Spark Gap X4/schematic.pdf. This is an example of what the designers have managed to incorporate into these Speeduino and other aftermarket ECUs. There is a significant amount of programming that goes with this, on my list to learn the "C" programming language. Can read it a bit, but there is a lot to learn as well.

Cheers