1985 GL1200 Limited ECU Replacement/Upgrade - Part 2

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Waiting for the info on the fuel injectors from Injector Experts in Ohio. The owner is an older gent like me. Last piece of the puzzle at this time. Cleaning up the bike, securing wiring and such, thinking of next wiring upgrade, yes going to redo what has been done - using the "better mouse trap syndrome", have a better mouse trap in mind.

Progressing my document on EFI Understanding - Explanation, now some 79 pages. I want this document to be different from the EFI handbooks, a more personal experience and journey.

There are no speed shops or tuning specialists on the Island so I have to become my own tuning expert. Putting this document together as well as having done some others (there are mistakes/misconceptions in them, only a few though) has improved my understanding of an EFI system immensely. It will be a while before I am finished with this document. Each review has me editing the information, correlating the information between the various sections. Going to look at some of my earlier musings and determine what if anything can be incorporated.

I've been putting together the interrelationship(s) between the various components, how these affect the tuning process. It's the what is it, what does it do, what does it interact with, the why and when all this is done. Takes a lot of the angst out of the equation. In doing this I have found a lot of information regarding best practice(s) as well.

Still waiting on fuel injector info - shop is progressing, but have decided to connect and go tomorrow. Tomorrow should be a good engine start, followed by VE table adjustment for a smooth base idle. Next will be a spark (ignition advance) table adjustment. If I have time, will look at the coil dwell and spark duration. Have to get some gas as well.

Been researching individual cylinder fuel trim (ICFT) and individual cylinder ignition trim (ICIT) - popped up on the Speeduino forum. Interesting concepts. ICFT is available for sequential fuel injector staging, but ICIT is not available for the Speeduino ECU.

ICFT is interesting because you could make a case that carburetor and engine cylinder bank (FI models) synchronization is actually a fuel trim procedure. This synchronization is all about fuel management at engine idle. I have been putting together a document reflecting this, heresy you say.

There is always an engine tuning parameter that I come across that needs to be researched and understood. I have mentioned that the better I know the requirements, the better will be the end result.

More to follow.
Today was a good day. Posted my thoughts on GL1200 ignition control module (ICU). Like it, just a few thoughts, more to follow on it.

Checked the Speeduino engine tune making sure that the tune was what I wanted and expected. Had a few connectors disconnected from the work done to date. Timing had been done a few weeks back.

Connected Speeduino to the bike, started it up and have been adjusting the VE and spark tables to suit. Have a sync issue that causes the engine to stumble every now and then. May have to take the rad off and clean up the new crank trigger wheel, only component that can give a sync issue.

Getting the VE and spark tables adjusted will let me set the base idle. Once this is done, determine what parameters I should adjust first and in what order such as enabling the WBO2 sensor.

Had a sync issue. This can only be from the crankshaft sensor. Went into the from top the engine and checked sensor air gap, 0.6 mm all round. Have read that the air gap may be a bit tight, will investigate.

Check the plugs, a wee bit sooty. Have to drop the feeling down to compensate, Req Fuel (RF) may need to be adjusted.

Looking into the dual wheel decoder setup again. Having a camshaft sensor allows for sequential fuelling or the use of coil-on-pugs (COP). I've read that sequential fuel injection is an environmental legislated requirement for new cars. Thinking the motorcycle world is there or heading there.

The camshaft sensor provides the engine phase (know where the intake and exhaust valves are) for the ECU.

If you only use a crankshaft position sensor, the ECU can only be sure of the engine crankshaft angle over a crank rotation of 360°. This limits the engine fueling options to operate the engine fueling up to semi-sequential fueling, and operate ignition in a wasted-spark configuration.

There are 2 revolutions of the engine crankshaft to complete a full engine cycle of 720°. Using a camshaft sensor allows the ECU to correctly determine a complete engine phase for an engine cycle of 720°. This is advantageous, resulting in better ECU operation even if it is not intended to use full sequential fueling, or coil-on-plugs (COP) or coil-near plugs (CNP).

Have ordered an inexpensive Hall effect sensor to install for the camshaft sensor. VR sensors do not well for low speed sensing. If it works will go back to the 8-tooth OEM trigger wheel.

Looked into the fuelling requirements for cold and warm engine starts. There is a cranking enrichment, after start (ASE) and warm-up (WUE) enrichment. These three parameters are a fuel percent multiplier meaning that the amount of fuel that would be needed IAW the VE table is augmented by a certain percentage until the engine is at normal operating temperature.

Cranking enrichment is the initial fuel injector pulse width adjustment and is in play until the engine starts. On engine start, the ECU uses the ASE table to augment the fuel required. For a cold engine this is approximately 20 seconds, a warm engine 1-2 seconds. The ASE is used until the ECU has stabilized the RPM and WUE has kicked in.

Once the engine is at base idle and normal engine operating temperature, the WUE should be at "0" or 100% which means that no more fuel enrichment is required. 100% is used as the value for no additional fuel augmentation because Cranking, ASE and WUE enrichment is a percentage value.

One I have a stable base idle, next parameters to be dialled in are the starting fuel percent multiplier tables, followed closely by the coil dwell tuning, and spark duration.

Hopefully have the fuel injector data soon. The fuel injectors need to be dialled in as well.
Have a sync issue to resolve. It is causing an engine stumble every now and then. Wasn't there before I did some changes, need to retrace my steps. Coils should not be an issue. The other major change was to the resistor caps, removed the resistor and used a piece of #10 copper wire in place. Will replace the resistors in the plug ups and have another go at it. Checked the crank trigger wheel for sensor spacing, 0.6 mm all round - should be good. Will check timing first. Once this issue is taken care of, should be engine tuning go.

Still toying with the idea of going to a dual wheel setup, crank and cam trigger wheel. Couple of reasons.

Will be able to put the OEM trigger wheel back on, worked well. Don't have to, but an option.

Regarding the number of teeth on the crank trigger wheel, read an article on the net that indicated a 12-1 missing tooth crank trigger wheel is common on motorcycles.

A cam trigger wheel as the secondary rotational input will allow for sequential fuel injection in the future. Only have to rewire the injectors to suit, additional in-line resistors too. Sequential fuel injection can possibly improve fuel economy, only fuelling one cylinder at a time, improve emissions as well because of this. Can keep the wasted spark.

It is to be noted that even if you are not going to do sequential fuel injection, or a COP install, the second rotary input signal is beneficial. Instead of the ECU only receiving an engine phase signal (relates to intake/exhaust valve position) every 360° of crank rotation from the missing tooth crank trigger wheel, the ECU will now receive an engine phase signal for a 720° of crank rotation - one full engine cycle, increasing the accuracy of the ignition timing.

Have a cam sensor design in mind that I can do with minimal garage tools. Need a hall effect sensor for the cam sensor. Had the engine running with the dual wheel setup when I first connected the new ECU.
Working and progressing the new ECU install. Have some engine sync issues that I believe are ground related, and will investigate. Installed a different TPS and have to calibrate it to suit. Ground issues with an ECU are routinely asked about. Even thought the grounds all go to the same point, the battery, it seems to be the separation of the grounds that is the issue. Having done some work with the coil(s) and the new coil driver, will investigate the ground point(s) separation.

Working on my EFI document and it is a good learning experience. Into the tuning aspect and what has to be done, and in what order. Not a lot of information regarding this; however, the more I delve into this aspect the more I am learning and I'm able to put together a sequence of events that need to be done and in what order.

I have looked at the engine starting aspect, I'm not very good at this aspect, but I'm working on it. Cold engine starting. This is my first draft at this topic, not a long one, but interesting.

I'm also researching tuning experts so to speak, and what is available, and how these experts got to where they are. Seems it's by the school of hard knocks. EFI training courses are available, but most of us that go down the road of an EFI conversion or upgrade are going to be our own tuners and doing the learning on how to be a tuner by doing a lot of research and reading - the old school way, then put into practice what we have learned.



  • EFI Undestanding-Explanation - 19 Jun 2023.pdf
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Why do you suspect ground issues? If because of false triggering, you might try ferrites on signal and power leads.
Going to address your question.

Had another trial this afternoon. Freshened the tune I am using. Checked the timing again, locked at "0" degrees. Connected everything back up and started the engine for a trial. No vacuum, engine just wasn't right. realized I forgot to unlock timing, things progressed much better after I did this.

Sticking with the VE table, adjusted some other parameters as I went along, but if no difference in the engine operating, reverted back to what I started with. Trying not to stray too far.

Had a "stumble" that started after the engine was operating for a bit. Not when cold, or when WUE kicked off because the engine was at operating temp. Gets worse and more often as time progressed.

If this is the case, a misfire is ignition related. Checked the temp of the coils with a finger check, seems fine. Should check the coil driver as well. Maybe the coil pack is not heating up enough to fail, but enough to not operate correctly, same with the coil driver.

The only mods I have done to the CFI system, is fuel and it is working well, coil pack and coil driver. Thinking to revert back to the original coils, worked well before. Can do a temporary install to test theory.

Have ferrites on the input signal wires:

More to follow.
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Sometimes, we have to be reminded to put the bullet back in our pocket (old Andy Griffin show reference). Shot myself in the foot many times. Latest was setting the tank down on the HT lead to #3 plug on my Trident T150V rescue. Luckily, the local auto parts store has a roll in stock that I can buy from by the foot. Now that old bike has started first kick, three times in a row. Eventually, things fall into place!
Another engine start after sitting all night. Have the engine starting whenever I want (fingers crossed, touch wood and such) Have been working on the tune to get a stable idle around the 950-1000 RPM mark. Leaving the idle alone, very small changes if any, adjust VE table - watch the AFR gauge. Adjust timing to lowest denominator so it won't stall. Small changes and it's starting to settle out. I know I want around the 15 degree BTDC mark at idle, or there about. There's still something not quite right in the lower RPM range - fuel/ignition. Will be looking into this.

Connected the OEM aftermarket coils I had in before. Doing the finger/hand test for temp, cool as can be. May look at changing the coil driver to test.
Yesterday, spent some time on the engine tune. Cranked in on the ignition timing at idle to 17 deg BTDC, brought the idle to a much better 950-1000 RPM. Engine starts much better. Will be trialing the engine with a different coil driver today-tomorrow (nice weather time for a ride on the Spyder). Have been thinking about the MAP value, still around 60 Kpa. Want this lower at idle speed - in the 40 Kpa range. Will be checking all vacuum hose connections - vacuum hose is new.

Spark plugs still a bit sooty. Have adjusted the Required_Fuel (RF) value by changing the fuel injector size in Tuner Studio. No definitive change from this as of yet.
Been a couple of days, the ECU install is progressing. Have been leaving it connected and starting the engine every morning, this is progress.

Paying attention to spark (timing) and fuel. Getting to a base idle, still have a stumble every now and then, but it will be smoothed out.

Required_Fuel (RF) setting being adjusted regarding number of injector squirts, injector flow rate, and injector staging. Will have to determine a testing procedure specifically for this.

Looking at the TPS setting. There is no definitive setup procedure for a new install. Will determine a procedure to address this.

Have decided to keep the newer coil driver - Bosch 211, and going back to the OEM coils. Better fitment and have been working well.

Noticed that the After Start Enrichment (ASE) was on for longer than needed when engine was at operating temp. Engine would run rough when the ASE was on, when it was off the engine smoothed out. This is a fuel percentage increase and when on, the engine was too rich. Adjusted the percentages to compensate for the time on. There is an ASE time function where you can adjust the amount of time the ASE is on immediately after engine start, this has been adjusted as well. Will adjust between the two as I go forward.

ASE has to be balanced against the Warm Up Enrichment (WUE) function that is used by the ECU until the engine is at normal operating temperature. Both will come on when the engine is started so the percentage form both have to be considered and the percentages adjusted to suit.

There is an Inlet Air Temperature (IAT) density fuel correction table to be considered as well. This is a fuel enrichment percentage depending on the ambient air temperature. Will have to consider this as I move forward.

The issue with all the fuel enrichment percentage tables is that these are always in play and cannot be turned off; however, these can be zeroed out.

There are volage correction tables for dwell and fuel injectors. These will be addressed in the near future.

Lots happening, but have to keep focused.

More to follow.
Have been making small inroads with the new ECU. Engine starts every time, but still has a stumble to it. O2 sensor does not appear to be working, will remove and test.

Have the information back on the fuel injectors, very interesting. The company that did the work for me has the OEM injectors flowing at 316 cc/min at 43.5 PSI instead of the 280 cc/min at 43.5 PSI (3 BAR). The fuel injectors were also tested at 58 PSI (4 BAR) flowing 363 cc/min.

The injector data has been forwarded and is what I was expecting:
Injector Data 1.JPGInjector Data 2.JPG

The owner did a comparison of the injectors to determine the fuel injector variance between each injector at 3 and 4 BAR. This picture shows the difference between the injectors, the 3 bar on the left:
Injector Data 3.JPG
This indicates that tuning the engine with the new ECU may not be as easy as thought. I was sent a picture of a set of Bosch 42 lb/hr fuel injectors for a comparison and the difference is significant:

Injector Data 4.JPG
Not going to let this information deter me. The issue is how far down this rabbit hole do I go. I mentioned to the owner that I would not be changing the injector setup, and that a change in injectors would have to fit what is there. Think I'll sleep on it.

It was mentioned that if there was another set of four injectors, to send them down and match up the best four. Would like to have 8 to send down, improve the odds. May be best option.

Was interested in the battery voltage that the Speeduino was registering. The tuning software indicates that the voltage at idle is 13 VDC. Multimeter between alt output and battery indicates 14.3 VDC. Don't know if this affects the tuning process. Have to chew on this as well.

More to flow.
Short morning work. Have adjusted the battery voltage in Tuner Studio to match the multimeter. Didn't notice a difference, but it is more accurate.

Going to swap out the fuel injectors for an aftermarket set I have to determine if the OEM fuel injectors are a bit off. Won't change any of the settings as this is being done to determine the status of the OEM fuel injectors and if the stumble can be attributed to the OEM fuel injectors. The stumble is at low RPM and idle. The OEM fuel injectors are some 38 years old.

Using three sets of spark plugs, use propane torch (the blue bottle) to burn anything off. Noticing that the plugs are not sooting up after a short engine run. Getting there.

Need to check the O2 sensor, AFR gauge reading not changing.

Have researched the Required_Fuel (RF) parameter. There are two numbers, one for the RF and the other for injector squirt time:
RF Calculation.jpg
Read through a lot of forum posts to determine what the RF value is all about. In the pic, the RF value is 6.2 milliseconds (ms), which is the time the fuel injectors will be open for one revolution of the crankshaft. The second value 3.1 ms is the fuel injector base pulse width that an injector will be open during an engine cycle - 2 crankshaft rotations.

The pic shows the RF calculator with my settings. The 3.1 ms value is based on (RF value X 2)/fuel injector base PW. The fuel injector base PW is determined by dividing the RF value by the squirts per engine cycle. Tuner studio automatically multiplies the RF value by 2. The injector staging, Alternating or Simultaneous, affects the fuel injector base PW.

The RF calculation shown above is for the Speeduino ECU application, how another aftermarket ECU determines these values may be different.

Read up on how the PW is calculated. This depends on the tuning software and the ECU being used.
Time for a short update. Have been working on getting the engine, OEM CFI system and new ECU integrated. The issue with engine timing is at the crux of my slow progress.

Have had an issue with timing, engine tune for years with the OEM CFI system. There is no ability to adjust the various CFI system tune to address issues.

The CX500/650 forum that I frequent is having issues with the '82/83 FI turbo models and the ECUs. There is a company in the Netherlands, Carmo, was sent an ECU and it is not repairable. Back to my ECU project.

Have been setting the engine timing by locking the timing in the tuning software, and setting the trigger angle for the "T" and "F" crank markings. This has been moderately successful, but not exactly what is needed.

Connected vacuum gauges to the engine to supplement the indicators in the tuning software. As was usual, the vacuum gauges indicted that there is an issue with valve timing and/or vacuum leaks, came in around 8 in HG. This has been historic for the past 8 years. Have chased a fuel smell on start(s), and lack of a fast idle.

Used starting fuel to check for vacuum leak(s), and did notice a very small change in engine RPM where the injector holders connect to the heads, and the air chamber. Going to get some new o-rings and install. Have been using what is available from a local hydraulic shop. Going to request one size larger.

The vacuum gauges shown here:
Cylinder Bank Balance.jpg
The vacuum gauges indicate that there is a vacuum leak and/or a valve timing issue. Not being able to change the engine tuning such as timing, makes this problematic. Have not seen other '85/'86 FI models with different results.

Making sure that I have not damaged the engine did a compression test 160 ish all round. Made sure the engine components were aligned properly. Then went back to engine timing.

Set engine timing for the crank "T" and "F" markings. Checked the timing using cylinders 3/4 as well as per the OEM service manual - pleasantly surprised it worked.

Started the engine with the various setting(s) and found that when I reduced the trigger angle (TA) from the base setting, and noticed the same annoying engine stumble. Increased the TA from the base TA and the engine started to come to life.

The vacuum gauges indicated a change as well. The vacuum reading(s) are now in the black area between the initial red warning of vacuum leaks and/or valve timing, and the red area for ignition timing - progress.

Check the spark plugs. Colour is brown to light brown. Once I get the engine timed as well as possible and address any vacuum leaks, can do further tuning.

Stumbled onto this scenario, but glad that I have. Thinking the better the engine vacuum at idle, the better the engine should operate on the road.

The 1200 engine with the CFI system is not intuitive, and is designed such that it is not to be played with.

More to follow.
Something like a car. Had a Jeep Liberty a few years back. Liked it, but it had a fault in the "black box" that controlled the ancillary functions. The techs at the shop did everything possible to fix the issue, but were relegated to RXR. Even talked to the wizards in Detroit with no joy. I've always been of the opinion that once your vehicle gets electrical/electronic "gremlins", time to trade it in.

Not that we "play with it", but we need an alternative to some essential parts to keep these venerable older bikes on the road. My friend up the street a couple of houses has a 2019 Mustang, perfect running order, so what does he do, you guessed it - modified it under the hood. Only issue he has is the tuner in Vancouver BC can not smooth out the engine at idle for street driving. He was told after the last dyno runs that it was as good as it will be, trying to digest this.

To be fair to this older gentleman, me, the OEM should have made a diagnostic unit that would allow me to "play" with the engine tune - shame on them.

I mentioned that the fellows on the CX 500/650 forum are feeling the crunch as well, ECUs are starting to fail.

I have mentioned somewhere about the ignition control module (ICU) that is on the carb GWs. These are long in the tooth and only available used when found. The Speeduino NO2C unit, slightly smaller profile than the OEM ICU, could be used for ignition/engine timing. Be a fun project, and there are efficiencies to be had.