[PSIG]

Honda was the king of lean-burn. Some of their engines were well over 20:1 AFR. Just a hair rich of lean-burn limit, enough added timing advance to cover for the slower lean-burn, and you're in the neighborhood. Some experimenting with injection end-point angle may help some at specific cruise speeds. Have fun!

[Rednaxs60]

I can work with this.

[Rednaxs60]

Project progressing. Have been addressing some wiring issues. Wanted a second Speeduino ECU for bench projects. Perused the various Speeduino suppliers and settled on the Spark Gap X4 by openlogicefi. Has all the features I wanted, specifically an on-board MAP and baro sensor, and a dedicated fuel pump connection. A few other favourable features/functions. Nice compact unit using the Arduino Mega Pro. Comes complete with OEM wiring harness connector and a case.

Had an issue when installing, could not get an engine sync. Corresponded with Aaron at openlogicefi, but no solution was could be found. Aaron was very patient and provided as much information as possible. Good service, happy with the product.

Thought about the issue and remembered seeing the dash go through a start initialization, meaning that the ECU had reset. I had seen this before but it was a one of type scenario.

Looked into the wiring, specifically the grounds. Did continuity checks of the wiring to the new ECU wiring harness connector, all good. Searched on-line for ECU wiring recommendations, and searched the Speeduino forum.

The issue was excessive voltage drop in the electrical system. I noticed that the ECU reset was only after 4 tries to start the engine. More research and a video by Andy Whittle regarding ECU grounding brought the issue to the fore. He recommended a quick test to determine if there was an ECU grounding issue. Disconnect the ECU from the wiring. Check for continuity between the ECU main ground wire and the sensor ground. Continuity - not good, no continuity - good. I had continuity - not good.

Removed the main ECU ground and the unused reference ground from the original wiring harness and connected these directly to the battery. Checked for continuity as mentioned, no continuity - good. Connected the new ECU to the CFI system, engine started, and full sync - all good.

Doing this quick test between grounds is recommended.

The grounding system for my Gold Wing is not that difficult to understand; however, all grounds go to one of two frame grounding points, then through the frame to the engine ground, then to the battery. If there are "dirty" (noisy) high power grounds such as the fuel pump, these affect the health of the ground system and affect the ECU that requires a "clean" constant power supply.

Note to self, do not expect an existing EFI wiring to be suitable for a new ECU installation, may be good, maybe not. I expect that the Honda CFI ECU had sufficient filtering that compensated for this issue.

Still working on and contemplating the digital dash tach signal.

Cheers

[Rednaxs60]

Question regarding fuel injector close angle. I have gleaned from this forum that this parameter setting applies to all fuel injectors equally. If additional fuel injector tuning is required, can be done with ICFT.

Question is with the degree setting. I have seen injector close angle diagrams that, going from left to right, start at "0" degrees to "720" degrees, other diagrams start at "720" degrees to "0" degrees. Both diagrams have "360" degrees in the middle.

I realize that fuel injectors do not close immediately, but wind down so to speak, and that a time of approximately 8 ms is needed to fully atomize fuel at idle - give or take. This atomization time will change as the RPM increases meaning that the amount of time to atomize fuel will probably decrease meaning that the fuel injector close time will need to be changed. Realize that there are other factors that can affect this parameter.

@PSIG mentioned in a post that fuel injector close times can been in the range of 100 to 160 degrees leading me to think that the diagram with, from left to right, the degrees are shown as "0" to "720". Having mentioned the above and for example, using 180 degrees as the idle start point that as the RPM increases minimizing atomization time, a fuel injector close time at 1000 idle RPM can be 180, 2400 RPM - 170, 3200 RPM - 160, and 150 for 4500 RPM and greater. This is with an understanding that up to 1000 idle RPM the fuel injectors will close at the 180 degrees, the ECU interpolates between 1000 and 2400, 2400 and 3200, 3200 and 4500. After 4500 the fuel injector close angle will be fixed at 150. Picture attached:

Valve Openings.jpg (68.69 KiB) Viewed 240 times

As with parameters such as this, experimenting will be required to optimize this parameter. I ask this question to further my understanding of engine tuning.

As an aside, the road trials and engine tuning is progressing well.

Cheers

[PSIG]

In a general sense, I would simply say that multiple load/rpm points should be tested for optimal efficiency. If working with code that only allows one end-point setting, pick the most advantageous load/rpm point (smooth idle, cruise economy, etc).

Note at higher loads and speeds, the angle would typically be later, as the mass flow (runner/port velocity) will be higher and 'travel' of the air/fuel charge quicker with reduced wall wetting and fuel dwell. Sort-of the similar relationship of O2 sensor lag/delay. Determine by testing.

[Rednaxs60]

Testing/road trials going well in between life's needs such as getting ready for Xmas.

Thinking about the loss of tach function.

The CFI system uses the injector signal from numbers 1 and 3 fuel injectors for the tachometer signal to the travel computer, once every engine cycle. I have searched on-line and this forum for information. There are several threads that discuss a circuit for a tach signal, using automotive relays and there was a mention of using fuel injectors as well.

I have a couple of fuel injectors available that I used previously that may fit the bill, and can connect these to the #1 fuel injector harness. Not concerned if the injectors are operating dry, but do need the ECU signal to trigger the injectors, or auto relays.

More to be thought about.

Any suggestions?

[PSIG]

Thinking about the loss of tach function.
The CFI system uses the injector signal from numbers 1 and 3 fuel injectors for the tachometer signal to the travel computer, once every engine cycle.

Any suggestions?

My approach would be to determine the signal characteristics required by the tach circuit. Then a source that would supply that signal type, once per crank revolution.

My interpretation of your description is one pulse-per-rev, yes? So, the right signal form (voltage, current, flyback, etc), based on your hardware configuration and operation. What does it need > where can I get that.

[Rednaxs60]

Rolled the test bed engine out today to determine what angles the intake valve opens/closes. Using #1 TDC as "0" degrees, intake valve starts to open at approximately 360 degrees after #1 TDC. It closes at approximately 560 degrees ATDC. The TS fuel injector close angle is set generically to 360 degrees. This information indicates that most of the fuel is injected onto a closed intake valve and should atomize well. Expecting that Speeduino uses #1 TDC as "0" degrees for the close angle, the fuel injector starts to flow fuel at approximately 160 degrees: 360 - 200 = 160. Not a lot of overlap between injector close angle and intake valve opening. Could move the injector close angle such that it closes at approximately 340 to 350 degrees, but this is one of those issues that leaving the close angle where it is is probably best, it's fine tuning for way down the road so to speak.

Thoughts/comments?