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Agreed about a quick finish. When you put the turbo water pump on I think it has 6 or 7 bolts and all seem to be different. Obviously the water pump bolt committee was in a hurry for production. The new pistons just represent the latest thinking on pistons in 2017 and I am hopeful that they are an improvement.
I keep drooling over those pistons you have created Edinir! The temptation is too much... must....order... PISTONS!!! Arghhh! :bdaypresent:
 

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Very interesting. So how much of the code is reverse engineered? Are you able to adjust fuel and timing as well? Would you be willing to share your findings and collaborate on creating an XDF definition file for tunerproRT? With that it may be possible to tune in real time with an emulator from Moates. Asking because we're thinking about going megasquirt on our bike but would try to work with the stock ECU if the tools are available!
 

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Discussion Starter #44
Very interesting. So how much of the code is reverse engineered? Are you able to adjust fuel and timing as well? Would you be willing to share your findings and collaborate on creating an XDF definition file for tunerproRT? With that it may be possible to tune in real time with an emulator from Moates. Asking because we're thinking about going megasquirt on our bike but would try to work with the stock ECU if the tools are available!
Well I will try to answer your questions but first let me explain something about the stock fuel system.

Honda apparently were so worried about driveaibility and functionality that they pulled out all stops on the design.
Important for any fuel injection system is to measure air flow, well on the CX500 there was simply no room available to place a MAF sensor so they had two options:

Speed Density - injection time mainly based on RPM and Manifold pressure

Aplha-N injection - injection time mainly based on RPM and Throttle opening

So what did they do , they used both ! :)

Speed density for low throttle openings and Alpha-N for high throttle openings.

But even that was not enough, they added a second computer processor to keep eye on the sensors if the outputs of the sensors were not within specification the ECU would go into limp mode so that the engine wouldn't be damaged butt still be driven home safely.

Further things to consider :
- fuel injection is sequential
- ignition is analog and has boost pressure compensation
- CX650 has digital ignition
- No wasted spark
- V-twin is odd firing and odd sequentail injection
- trigger wheel for ignition has only one tooth
- trigger wheel CX650T has 9 tooth but no missing tooth

All of this makes this an odd bal in Fuel Injection control land

I would love the have an eprom emulator running to change real time the parameters.
Problem is that the eprom is a 2716 (2K) eprom and is not supported by Moates and probably the software will also not support dual injection modes.

I would like to run something like a Megasquirt.
Problem it support for V-twins is not so good.
It can run a V-twin but then you lose different options on peak and hold injection driver.
It doesn't support a dual mode injection.

I think anybody who wants to change the fuel/injection system does that to get more horsepower out of the engine. Because the OEM system is already so good the replacement should be better.

My requirements for a full racing replacement system would be roughly

- Sequential fuel injection
- End of fuel injection pulse control
- Dual mode speed density + Aplha-N
- Wide band Lambda sensor
- Odd firing ignition with dwell time control
- Intercooler temperature output/input
- Turbo RPM sensor output/input
- Electric wastegate
- Electric Turbo blow off valve
- Fully indepentend fuel and ignition timing on each cylinder

That being said so far I now rougly how the fuel injection timing is done and which tables in the Eprom have to be changed.
A lot of data inside the eprom I am still unsure about such as voltage compensation, atmosperic pressure compensation etc
 

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Thanks for the thorough explanation PIM! Proves Honda likes to (over?) engineer things. I prefer a straight up SD tune so I'll break out the o'scope and see what signals we have to work with. Hope not to reinvent the wheel much but not many are detailing their experiences modifying the OEM system.
 

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Pim205GTI, I have read and re-read this post with great interest. The burning question is, are you making your research available to others?
 

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Discussion Starter #48 (Edited)
Pim205GTI, I have read and re-read this post with great interest. The burning question is, are you making your research available to others?
I am not trowing my research data and results and findings on the open internet. I have spend a considerable time and money to get this far.

I am now working together with Edlinr on his landspeed records attempts. I help him and he helps me ( and a lot of other forum members )
 

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thanks and I understand how much work you have put into it and that I have come out of nowhere asking for help. Please note that I appreciate all you are doing and what you have shared!

I am going to give it a crack myself before hitting the bike further with my purse (aka microsquirt) so I thought I should at least ask. Build thread to follow...
 

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I am not trowing my research data and results and findings on the open internet. I have spend a considerable time and money to get this far.

I am now working together with Edlinr on his landspeed records attempts. I help him and he helps me ( and a lot of other forum members )
PIM - just found your thread. Very good read. It is also of interest because I am looking into an ECU upgrade/replacement for the ECU on my '85 GL1200 LTD. Honda did over engineer the FI system, and with the '85 GL1200 LTD, integrated the LCD dash, and travel computer. I want to keep this integration of these components.

My reason for doing an ECU upgrade/replacement project is that these units are 35 years old and if fails, the bike might as well be a boat anchor. So I have looked into the Megasquirt products as well as the Speeduino project. I have settled on the Speeduino project and finding out there is more to adapting then just a buy and try. Need parameters for a lot of the components, and a lot of other info. Giving myself a year or two as the bike is operating well at this time. The only issue I have presently is with the TPS, had to replace the OEM component with an aftermarket one. Using an aftermarket TPS has installation issues. I also installed an external alternator that makes space for an aftermarket TPS install very tight.

Have a second ECU that has a 5V fault that I will be looking into.

Always get good ideas from the various threads.

Cheers
 

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After reading your thread, I looked for EEPROM readers on line. Think I'll get one as these are not expensive, and take the chip out of the second ECU I have. Have to find one that will take a 24 pin EEPROM.

As an aside I was at a local electronics shop for a different reason and asked if they had an EEPROM reader. The fellow behind the counter, an older chap, mentioned that it had bean a long time since anyone had asked for such a device. Showing my age I guess.

Cheers
 
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I finally found time to get into the EPROM. Found a few tables, built an XDF for TunerPro and headed to the dyno. The system was commanding around 15:1 with the mods we'd performed but after a few tweaks we have 11.5:1... the one thing I couldn't find (ran out of dyno time) is the transition from SD to alpha-n where it invariably went from 12:1 to around stoich and then back down to the ratios we want. Not a big deal but I would like to find that eventually.



202570
 

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Discussion Starter #53 (Edited)
the one thing I couldn't find (ran out of dyno time) is the transition from SD to alpha-n where it invariably went from 12:1 to around stoich and then back down to the ratios we want.
The transistion is directly related to the throttle opening and is happening at very low settings, maybe 20% or so.
So if you go for flatout horsepower / WOT you do not care to much about the "Speed Density" region

I would read the Honda Fuel Injection Manual, it explains really well how Honda designed this ECU
 

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Pim - is this the manual you mention? CX500T Fuel Injection Manual.jpg
 

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The transistion is directly related to the throttle opening and is happening at very low settings, maybe 20% or so.
So if you go for flatout horsepower / WOT you do not care to much about the "Speed Density" region

I would read the Honda Fuel Injection Manual, it explains really well how Honda designed this ECU
Thanks Pim. I was handling it like a normal map and yes it did seem that changes in the lower regions were having more effect. We all agreed that it's not the most important region to "fix" but when we get back in town, we'll try to improve on out understanding of the system and clean up the tune. Doin everything at the last minute as usual... too many responsibilities!

BTW, I found an emulator that works with the 2716... haven't been able to use it so I'll post more on that later. Also, AT28C16 EEPROMs work fine and help effect changes quickly.
 

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I am knees deep in my /82 CX500T resurrection project. I got the bike 8 years ago and it wasn't running. It did however crank over and had excellent compression so I decided to go for it.
Last week I had the opportunity of being brought another one that had been sitting for a long time and I was asked to get it running. Without much work I was able to get that done and took the opportunity to test out my electronic components. All the PB Sensors, ignition module, coils, regulator all tested good but when I plugged in the ECU the "Fuel System" light never lit up and the engine would not start. Cranks over but that's it.
I started to suspect that I might have a problem when I tore the tape off the main wiring harness and found that the ground wire had overhead and melted a mass of wires together inside the loom.
Is there another way of setting these up besides the original ECU and what would I need to do that?
Or...is there anyone out there that can repair this one?
 

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Curlay, you should start a new thread.
 
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