1985 GL1200 Limited ECU Replacement/Upgrade - Part 2

[Rednaxs60]

The original thread is getting long and is a bit dated: viewtopic.php?t=67329

Started a thread on the Classic GW forum regarding the CFI ECU Tuning and Data Analysis Software, Tuner Studio (TS) and MegaLogViewer (MLV) https://classicgoldwings.com/threads/cf ... ost-231475

I regularly review these software applications and learn something new every time. Doing some wiring upgrades, and have a trial to do regarding the dash tach indication. When I started this project and did first engine starts, January 2023, had a dash tach indication. This was with wasted spark and paired fuel injectors. The tach input signal to the travel computer comes from 1-3 fuel injectors. Hoping a change back to paired fuel injectors works, keeping sequential ignition.

Have come to realize that paired fuel injectors is probably as efficient as sequential fuel injection. Sequential fuel injection is best for idle/low powers regarding emission standards. The GL1200 ignition sequence is 1-3-2-4. Fuel injected into cylinder 3 at the same time as cylinder 1 does not hang around very long, probably milliseconds, so the gains that may be had with sequential fuel injection are not that substantial.

Sequential fuel injection does have benefits and specifically, that is Individual Cylinder Fuel Trim (ICFT). This is a feature where you can calibrate the amount of fuel a fuel injector will inject into the cylinder based on the calibration of the ICFT table for that cylinder (maximum of four cylinders). This can assist in balancing the cylinders so that each cylinder is doing the same amount of work, very beneficial at idle and lower engine powers. This feature negates, maybe not eliminate the need for a balanced set of fuel injectors; however, we the laymen may not notice an improvement in engine performance.

Will continue to report. If there are questions regarding an EFI conversion/installation, feel free to ask. I like anything EFI.

Cheers

[Rednaxs60]

My detailed review of the TS application has been very illuminating.

Paired injector layout versus semi-sequential fuel injector layout has been referred to as the same. I submit that there are similarities, but a difference that is significant. Paired fuel injectors use two channels for a four cylinder engine, semi-sequential uses 4. Semi-sequential fuel injector layout uses the engine cylinder timing sequence to pair fuel injector circuits. For example 1200 GW firing sequence is 1-3-2-4. Injector circuit one goes to #1 cylinder, #2 injector circuit goes to #3 fuel injector, #3 fuel injector circuit goes to #2 fuel injector and #4 injector circuit goes to #4 fuel injector. When you choose the semi-sequential fuel injector layout, a new drop down box appears allowing the user to choose the correct cylinder ignition timing, in this case 1-3 and 2-4. The ECU uses this setting to pair the appropriate injector circuits for firing. The setting chosen for fuel injector layout depends on what you need to use the layout for. In the case of an '85/'86 1200 GW FI model, injectors 1-3 are used for the tach signal. Semi-sequential cannot be used for this requirement.

Throttle body injection (TBI) versus Port fuel injection layouts. Both are used, but each has pros and cons. TBI fuel injection is widely used because, IMO, it is easier than fabricating a special fuel rail as would be required with Port fuel injection. TBI is better than using a carburetor, uses many more input signals such as a TPS, IAT/CLT sensors, battery voltage corrections, and such. There is the issue of wall wetting/fuel puddling. Tuning for an engine cold start is more challenging. Spraying fuel into a large plenum when the engine is at normal operating temperature will atomize the fuel charge, but the issue is where does this fuel charge go especially in a car intake manifold, to where it is intended, or elsewhere - it is a bit of a crap shoot, but still works well for normal everyday operation. Using TBI fuel injection for a motorcycle EFI conversion project is probably close to Port fuel injection without the fuel injector being close to the intake valve, but not as close as with Port fuel injection.

Port fuel injection is where the fuel from the fuel injector fuel charge is sprayed directly, or as close as directly as possible onto the cylinder intake valve. The cylinder intake valve heats up quite quickly, atomizing the fuel charge quickly. Fuel injectors are generally downstream of the throttle plate(s), as in the '85/'86 1200 GW FI models, and as such, the fuel charge goes to where it is destined for. Very little fuel puddling/wall wetting occurs with Port fuel injection.

I've been reviewing the TS and MLV apps to further my knowledge of these. Have reviewed and researched injector close angles. Speeduino has this setting, but it is used to set the degree at which the fuel injector ceases fuel injection. The Mega Squirt family of ECUs have a start, middle and end setting. Lets' discuss the end setting. Using the end state for fuel injection means that you want the fuel injector fuel flow to stop at a specific engine timing. This can be before the intake valve opens, when the intake valve is open, or overlaps the start of the intake valve opening. There are a variety of reasons for injecting the fuel charge before the intake valve opens, should atomize the fuel charge completely and when the intake valve opens, the atomized fuel is quickly sucked into the cylinder to be compressed in the compression stroke. Having the fuel charge discharge into the open intake valve has advantages as well, maybe cooling the cylinder, additional cylinder lubrication and so on.

Experimenting with the injector close angle may result in a recalibration of the VE table. It is also recommended that adjusting this setting is done after the VE table is well calibrated.

Experimentation to determine the best engine performance and fuel economy may be needed if you wish to pursue this feature. For myself, I would think having the fuel charge in the runner before the intake valve opens should work the best, just my opinion.

One last item for this post, fuel economy. My '85 1200 GW FI model routinely got 45 to 50 IMPG when cruising and two up riding. This indicates to me that Honda did a good job of tuning the engine and operating with a lean air-fuel mixture. I have floated this idea on two other forums and the response has been that Honda is the "King" of the lean burn, some people seeing AFR readings in the 16 to 19 range, extremely lean.

To achieve this, the VE table cell values need to be reduced to limit the amount of fuel being injected into the engine, and ignition timing must be such that ignition timing to start the fuel burn is just on the fringe of being too advanced, but enough to ensure a complete fuel burn at the 10 to 15 degrees ATDC. I would surmise that closer to 10 degrees ATDC may be better. This will be explored.

A few more thoughts to ponder. Cheers.

[Rat]

I thought so …

Gord

[Rednaxs60]

My research has found that Honda is known as the lean-burn "King" of automobiles. This premise is sound because back in the late '60s/early '70s when the Japanese OEMs invaded North America, the Japanese cars delivered better fuel economy. I heard a story that the Japanese OEMs were questioned about this, and the answer; people want fuel economy. Environmental legislation came to the fore. North American OEMs added external additional parts to meet this requirement, the Japanese and offshore OEMs retooled the engine and added needed external parts, different design philosophy and a better one.

The late '70s and early '80s saw the ringing in of EFI systems. I mentioned on a thread that when EFI systems started to become mainstream, my father, whose livelyhood was being a mechanic - loved growing up at his gargage, thought he'd won the lottery, reduced service calls especially in the winter, carbs were a PITA.

Getting back to the lean-burn. Have read many a forum post regarding this and that Honda engines operate well at 15 to 19 AFR readings. This allows for very good fuel economy, and is a testament to the engine design. My '85 1200 GW FI model routinely achieved a fuel economy of 45 to 50 IMPG solo and two-up when cruising. This is approximately 5 litres per 100 Kms. To accomplish this the engine must be operating in a lean-burn condition, and will be high on the priority list for final engine tuning. Something like the engine tolerances of today and the specified engine oil is say 0W20, whatever happened to 10W30, go figure:

Oil Can.jpg (125.47 KiB) Viewed 1593 times

The Royal Enfield Himalayan is another example of a well tuned, lean-burn engine. It is designed for the back roads around the Himalayans and other similar areas, not many gas stations around. My ex-2021 Himalayan achieved a respectable 90 IMPG. I will own another one, not just yet.

Having mentioned the above and what I posted previously, it is worth exploring these additional tuning features/functions should you embark on an EFI system project.

Cheers

[Rednaxs60]

Project is progressing, Spark Gap X4 ECU from openlogicefi has a been installed, wiring harness connector changed, and engine is operating with the new ECU. There's a lot to know about EFI and its idiosyncrasies.

Had a couple of issues to solve. First was related to the Hall Effect sensors (HES). I was getting no engine sync. Contacted openlogicefi, prompt reply from Aaron - good service. The v0.4.4 board has a jumper that you configure for a 1 kOhm pull-up resistor for the HES. The X4 board needs to have the same jumper closed, but you need to drop a dob of solder on the jumper to do this. Next was the "no sync" issue.

The OEM CFI system always gets a bad rap, and is generally the scapegoat for a lot of issues. Many times we, the owners of the '85/'86 1200 GW FI models, tend to go down the rabbit hole regarding troubleshooting. Good example is the TPS. Blamed for fuelling issues on start, poor fuel economy and the likes when in reality, the TPS has nothing to do with the engine feeling, just indicates to the ECU when the throttle plates are closed or being opened.

Aaron at openlogicefi, owner, operator and designer - one man show, and I had correspondence regarding this issue. I was looking at the X4 as a probable cause, he was certain it was not (he was correct). As an aside, good service from Aaron, highly recommend his products as a consideration for an EFI install.

Remembered seeing the CFI system reset on one of the engine start trials. This has happened before, but I paid no attention to it since I'm dealing with an FI system to start with.

This time I decided to delve into a possible grounding issue(s), shouldn't be necessary since the OEM wiring harness is being used for an EFI system, so I thought.

Lots of information on-line regarding wiring an ECU into an EFI system. How to ground the ECU properly, where to ground it and the engine electrical system(s), and what can/could happen if not correct.

The issue I was having was because of a significant voltage drop in the ECU because of the interaction with other components in the electrical system such as fuel pumps, coil-on-plug (COP) units, fuel injectors, rad fans, starter and such. This voltage drop was causing the ECU 5V reference voltage to be non-existent and as such, the Hall Effect sensors were not sending a signal to the ECU for engine sync, hence, no engine start.

The ECU requires a "clean" stable power supply, and is a "power pig" - fact of life.

The high power grounds, "dirty" grounds impact on this. Outside influences can drop the voltage in the electrical system sufficiently to rob the ECU of adequate power, ergo, ECU shuts down and does not come back on-line until power is restored - system reset. This voltage drop occurs quite quickly.

Found on-line a quick test to perform to determine if there is an ECU ground issue. The ECU has sensor reference ground circuits, and if a sensor reference ground circuit is not used it must be tied to the main ECU ground.

The X4 has three ground reference circuits of which I have used two, one for the input sensors such as CLT/TPS/IAT and Hall Effect sensors (HES), the third is not used an is tied to the main ECU ground through the OEM wiring harness.

The test is to disconnect the ECU from the wiring harness and do a continuity check between the ECU main ground and the sensor ground pins. Continuity - yes, not good - no continuity - yes, good. I had continuity. Recommended troubleshooting fix is to disconnect the ECU main ground and any other ground tied to the ECU main ground and go directly to the battery. This bypasses the wiring harness that has a plethora of green ground wires throughout.

Once done, check for continuity. In this case no continuity - good, can move on. Reconnect the ECU, tried a start, engine started and all seems to be good.

The takeaway from the above is that a simple one minute test such as this can progress your troubleshooting and in the right direction. The CFI system has probably had operating issues because of the OEM wiring and I have not been aware of, or disregarded - easy to do especially if a fault is intermittent.

I also wonder if the ground wiring for the 1200 GWs, carb or FI, could be an issue resulting in some of the charging system problems. The ignition control unit, regulator/rectifier, CFI ECU are all electronic components and electronics components do not like electrical system fluctuations, something to ponder and consider.

I had a flashback moment and compared the original OEM CFI ECU to the new Spark Gap X4. It's amazing what can be stuffed into a small package nowadays, and the capability of these new ECUs is significant. Pictures of the new verse old ECUs:

Old-New 1.JPG (147.06 KiB) Viewed 1373 times

Old-New 2.JPG (131.29 KiB) Viewed 1373 times

Old-New 3.JPG (94.25 KiB) Viewed 1373 times

There are a couple of features that the original ECU had such as a self-diagnostic program - very helpful, and you may or may not retain a dash tach readout (working on this one).

Have an issue with the TPS reading, not what it is supposed to be investigation required.

Cheers

[Rat]

I wish I could help … but …

Gord

[Rednaxs60]

No worries. Great project bike and keeps the creative "juices" flowing. It's like the movie The Martian - there are issues that need to be addressed, fix one at a time and you may be able to come home.

The progress is going in the right direction. Wiring may change before next riding season, but don't want to keep the bike off the road too long, need to progress the engine tune.

Have to decide how to mount this ECU in the same place as the original ECU. It's a fraction of the size. Still working on the tach issue. The fuel injector and coil wave forms appear to be similar. Honda triggered the tach issue with numbers 1-3 fuel injectors. I'm thinking that fuel injectors 1-3 are fired once every engine cycle (720 degrees). More on this as the project develops.

I have used Tuner Studio Tune Analyze Live feature to adjust the VE (fuel) table as I ride. Not the end all be all, but brings the tune into focus faster than a start/stop manual adjustment methodology. This feature compares the VE table cell values and uses the AFR table cell values to determine if the VE table cell values should be changed or not. I will be adjusting the spark (ignition timing) table to advance the timing just enough to ensure a good burn at the correct time. Tuning to AFR values is not a recommended tuning process, but you do what you have to.

Hopefully be out this weekend for some enjoyable riding weather permitting.

The modification to the OEM CFI system has been extensive, modernization. Changed the wiring harness connector, fuel supply system upgrade, different spark unit (coil driver), coil-on-plug (COP) units, sequential fuel and ignition, Hall Effect sensors in lieu of the OEM VR sensors, one cam sensor instead of the two OEM sensors (different application), ECI on board MAP sensor (1) instead of the two PB sensors, and some wiring changes as mentioned. Do not believe I will be reverting back to the OEM CFI design any time soon.

Have a new schematic that is quite detailed for this project. As long as the new CFI system is well documented, not an issue. Will be thinking about divesting myself of a lot of components for a CFI system that has not been modified such as ECUs - have two good ones. Will be doing a list of what I have available and will be letting go. Can't keep everything.

Cheers

[Rednaxs60]

Did a show and tell at a friends place this week. He is laid up, new hip. Showed him the 3 ECUs, OEM, Speeduino Interface board with an Arduino microcontroller and the new Spark Gap X4 with the Arduino Mega Pro. As mentioned technology has come a long way:

Old-New ECU.JPG (111.35 KiB) Viewed 1302 times

Spark Gap MAP Sensor.JPG (96.58 KiB) Viewed 1302 times

The second picture shows the difference in the MAP sensors. The larger Map sensor is the go to sensor, the smaller MAP sensor is a good alternative.

I review the EFI conversion threads on these forums to determine if there is more info to think about, maybe use, as I progress my engine tune. Look at the VE (fuel), spark (ignition timing), and AFR tables cell values. Fuel enrichment, coil dwell settings, correction factors, and the likes.

My friend mentioned that I am a bugger for punishment in that a lot of DIY EFI conversion efforts would be collecting dust by now. There are a lot of bench projects that are mostly used for concept development, but the proof of a bench project is installing the bench system in the vehicle and making it work - the interesting part. Should start a survey to determine how many EFI GW conversions have been done, in the conversion stage, thinking about it, or tried but it's now a dust collector.

I was asked at the start of my project if I was going to do a fuel or ignition install first then progress to the "full monty" upgrade. I mentioned that the project was all or nothing.

There is a forum called "Discord". Hardware, ECU development, component discussions, and much more is found here. Web site: https://discord.com

The amount of information is considerable, but it's a window into various topics. Reading for when you can't get to sleep.

I'm trundling down this EFI highway and will get back on topic next post. The better half asked if my project bike would ever be finished, probably not.

Cheers

[Rednaxs60]

I have put together a basic document regarding a basic OEM CFI ECU replacement project keeping the OEM CFI system wasted spark and paired fuel injectors. The aftermarket Speeduino ECU that forms the basis for the replacement is the Speeduino interface board v0.4.4 with an Arduino Mega 2560 sister board. I have configured this Speeduino ECU and used it on my '85 FI model. The document is in PDF format and I have it posted in my thread on the Classic GW forum. I am entertaining comments/suggestions to improve it: https://classicgoldwings.com/threads/85 ... ent.15615/

Cheers