First Post - have mentioned fellows from the NGW forum, but have found most of my information over there, even seen posts from younger versions of Joe and Dan. It's going to be an interesting quest. Have sent an email to DIY regarding the Megasquirt unit.
Still have a fuel/oil smell and some blue smoke on start. Investigated this. Pressurized the fuel system and did a borescope inspection of the backside of the intake valves. All four cylinders dry. Checked numbers 2 and 4 cylinders after sitting for a night on the side stand. Number 4 cylinder dry, number 2 cylinder some oil:
Not a big issue, but annoying. This will be the main item I will take care of this coming winter, rings and remove cylinder glaze. When I had the heads off, you could see the original cross hatch marking, but the cylinders were quite shiny. This work should finish off the mechanical work this bike needs.
Now to the subject of this thread. I have been learning about the CFI system since I bought the bike. I researched it before I bought it and some items came to the fore such as TPS and crank angle senor (Ns) replacement. Other areas that have been looked at and I have replaced are the PB sensors (MAP) with more modern Suzuki MAP sensors - better technology than the older Honda OEM Pb sensors.
The TPS is a linear rheostat so just about anything works. There is a catch with this in that the QA for these TPS components is sketchy at best. New TPS components can be problematic, found this out the hard way, right from the start. A faulty TPS can make the engine have "hard" misfires that feel like the engine is going to stop. Found a web site that had oscilloscope graphs showing good and faulty TPS components that were new. The faulty components had a lot of chatter in the mid range voltage that would send a faulty signal to the ECU and the ECU would react accordingly. Heat also affects these components adversely as well.
The Gr/Gl sensors - commonly called PG sensors - located on the back end of the right cylinder head, are not available but the folks over on the CX500-CX650 turbo forum have found the LX579 Sensors used in Dodge products are a suitable replacement component.
I have replaced the Ns sensor as well. My bike had the 1500 mod where the engine case had to be modded to allow the 1500 sensor to fit. I replaced this with a set of PG sensors from an '85 Aspencade that fit in the timing belt area. I have both installed but only use one. The second one will be a spare in case the one I am using fails. In having the second sensor installed won't have to get into the timing belt area, just have to switch the wiring under the shelter.
The primary components that make up the computerized fuel injection (CFI) system are:
Air temp sensor (T1)
Manifold pressure sensors (PBr/PBl) qty 2 - one for each cylinder bank
Throttle position sensor (TPS)
Coolant temp sensor (Tw)
Crankshaft angle sensor (Ns)
Cam shaft angle sensor (Gr/Gl)
Fuel pump relay
CFI main relay
Fuel shut-off sensor
ECU
I have been reviewing the literature about the Megasquirt unit and it is quite comprehensive, and there is a lot of it. I also read/reviewed the various forum threads regarding EFI projects.
Socrace, thesteve, irishcarbomb, toehead, FirstYearDeek, and taunusrainer (lots of other threads but can't mention everyone) threads have been very informative.
So far I have yet to find a thread on just an '85/'86 GW fuel injected bike ECU upgrade/replacement. My quest will be to, hopefully, achieve this without too much modification/component change out. I am intrigued; however, with socrace's use of Ford COP, and the various spark igniter units mentioned in the Megasquirt literature. The wasted spark coil in the Megasquirt literature is also interesting. Socrace also mentions that the spark igniter units used in the '85/'86 FI systems can be used.
I read on one of the threads where it was mentioned why one should go with EFI and the benefits of such. For myself, I prefer FI over carbs. When EFI came mainstream in the auto industry, my Father being a mechanic, thought he'd won the loto. Cold winter mornings, boosting and getting flooded cars going dropped to a minimum. Carb and EFI have issues. I believe socrace mentioned that dong an EFI project is like owning an older vintage bike, not for the faint of heart, and nothing is inexpensive.
The dual PB (MAP) sensors used by Honda has not been explained, and questioned in a few threads. I have read where a fellow did "marry" the two into one, use a splitter to connect back into the system and everything worked fine. I think this is completely plausible. To upgrade to the Megasquirt unit, this is probably what will have to happen - not a big issue.
Socrace has mentioned that the Honda OEM TPS can be used, but any linear TPS can be also. Have used a TPS for an early model Civic as a replacement for the Honda OEM unit, worked fine once I got a good one.
The '85 LTD has an 8 tooth trigger wheel for the crankshaft sensor (Ns). Read about using a 36-1 but would have to research this. The GL1500 has a 12-1 trigger wheel that would probably fit in place of the '85 LTD Ns 8 tooth trigger wheel. Possible alternative.
The Gr/Gl (PG) sensors on the backend of the right cylinder head was mentioned in the Megasquirt manual. Single tooth that will apparently work, but a change to a 12 tooth trigger in place of is recommended.
There is discussion regarding the OEM injectors for the '85 LTD. I had mine cleaned and the flow results came in at 65 ml/min after cleaning. The numbers before cleaning were 64 ml/min. Pressure setting for injector test(s) was 40 PSI. The injector resistance reading was 2.6 ohms for each. The original Honda OEM injectors are quite robust. These injectors are being used in several projects and I have been taking notes regarding the injector impact on tuning the EFI system.
The fuel pump requirement is for 630 cc/min minimum. Static pressure is 34-38 PSI and dynamic 28-34. My system came in at 38 PSI static, and 36 PSI dynamic. When I was searching for the reason I had a fuel/oil smell on start, I pressurized the fuel system and let it sit. Pressure dropped 12 PSI in one hour. Think this is a bit excessive so I am looking for a suitable fuel pressure regulating valve that will fit where the original is.
The idle air control system is a passive system that works quite well for its design. The idle air control (IAC) valve is activated by a bi-metallic element (courtesy of socrace). The IAC valve is wired in parallel with the fuel pump - fuel pump on power to IAC valve. It is never fully closed even when cold and not used for a while. The water system hoses connected to the IAC valve are to prevent freeze up in colder climates, other than this requirement, no need to have a water heated valve. The reed valves work quite well and are operated by cylinder vacuum. I replaced the IAC system hoses, but when I installed the air chamber one of the hoses came off the right side reed valve (had to remove air chamber to repair). These reed valves suck a lot of air and the noise is quite loud. If you did not know better, you would think there was a metal on metal issue, I did, But when I investigated using a stethoscope (Long screwdriver) there was no internal metal noises. The Megasquirt literature I have read indicates that this passive IAC system is acceptable.
Here are twp pics of the IAC valve internals. This is when cold:
This when bi-metallic strip heated opening IAC valve:
There will always be IAC system air going into the engine. The IAC system is not just for operation when cold, but provides air when the throttle is shut, cutting off air to the cylinder(s). A small amount of air bypasses the throttle plate(s). Here is a picture of the IAC system:
You can see the reed valves and where the output from the reed valve(s) is on the cylinder side of the throttle plate(s).
I mentioned that a hose came off the right side reed valve when I out the air chamber back in. The hose size is approximately 1/2 inch or so. This is a picture of what I found:
The lower arrow is where the IAC valve gets its air supply.
I think I've come to the end of my introduction into the Megasquirt world, and the quest for a suitable ECU upgrade/replacement. More to follow.
Cheers
Still have a fuel/oil smell and some blue smoke on start. Investigated this. Pressurized the fuel system and did a borescope inspection of the backside of the intake valves. All four cylinders dry. Checked numbers 2 and 4 cylinders after sitting for a night on the side stand. Number 4 cylinder dry, number 2 cylinder some oil:
Now to the subject of this thread. I have been learning about the CFI system since I bought the bike. I researched it before I bought it and some items came to the fore such as TPS and crank angle senor (Ns) replacement. Other areas that have been looked at and I have replaced are the PB sensors (MAP) with more modern Suzuki MAP sensors - better technology than the older Honda OEM Pb sensors.
The TPS is a linear rheostat so just about anything works. There is a catch with this in that the QA for these TPS components is sketchy at best. New TPS components can be problematic, found this out the hard way, right from the start. A faulty TPS can make the engine have "hard" misfires that feel like the engine is going to stop. Found a web site that had oscilloscope graphs showing good and faulty TPS components that were new. The faulty components had a lot of chatter in the mid range voltage that would send a faulty signal to the ECU and the ECU would react accordingly. Heat also affects these components adversely as well.
The Gr/Gl sensors - commonly called PG sensors - located on the back end of the right cylinder head, are not available but the folks over on the CX500-CX650 turbo forum have found the LX579 Sensors used in Dodge products are a suitable replacement component.
I have replaced the Ns sensor as well. My bike had the 1500 mod where the engine case had to be modded to allow the 1500 sensor to fit. I replaced this with a set of PG sensors from an '85 Aspencade that fit in the timing belt area. I have both installed but only use one. The second one will be a spare in case the one I am using fails. In having the second sensor installed won't have to get into the timing belt area, just have to switch the wiring under the shelter.
The primary components that make up the computerized fuel injection (CFI) system are:
Air temp sensor (T1)
Manifold pressure sensors (PBr/PBl) qty 2 - one for each cylinder bank
Throttle position sensor (TPS)
Coolant temp sensor (Tw)
Crankshaft angle sensor (Ns)
Cam shaft angle sensor (Gr/Gl)
Fuel pump relay
CFI main relay
Fuel shut-off sensor
ECU
I have been reviewing the literature about the Megasquirt unit and it is quite comprehensive, and there is a lot of it. I also read/reviewed the various forum threads regarding EFI projects.
Socrace, thesteve, irishcarbomb, toehead, FirstYearDeek, and taunusrainer (lots of other threads but can't mention everyone) threads have been very informative.
So far I have yet to find a thread on just an '85/'86 GW fuel injected bike ECU upgrade/replacement. My quest will be to, hopefully, achieve this without too much modification/component change out. I am intrigued; however, with socrace's use of Ford COP, and the various spark igniter units mentioned in the Megasquirt literature. The wasted spark coil in the Megasquirt literature is also interesting. Socrace also mentions that the spark igniter units used in the '85/'86 FI systems can be used.
I read on one of the threads where it was mentioned why one should go with EFI and the benefits of such. For myself, I prefer FI over carbs. When EFI came mainstream in the auto industry, my Father being a mechanic, thought he'd won the loto. Cold winter mornings, boosting and getting flooded cars going dropped to a minimum. Carb and EFI have issues. I believe socrace mentioned that dong an EFI project is like owning an older vintage bike, not for the faint of heart, and nothing is inexpensive.
The dual PB (MAP) sensors used by Honda has not been explained, and questioned in a few threads. I have read where a fellow did "marry" the two into one, use a splitter to connect back into the system and everything worked fine. I think this is completely plausible. To upgrade to the Megasquirt unit, this is probably what will have to happen - not a big issue.
Socrace has mentioned that the Honda OEM TPS can be used, but any linear TPS can be also. Have used a TPS for an early model Civic as a replacement for the Honda OEM unit, worked fine once I got a good one.
The '85 LTD has an 8 tooth trigger wheel for the crankshaft sensor (Ns). Read about using a 36-1 but would have to research this. The GL1500 has a 12-1 trigger wheel that would probably fit in place of the '85 LTD Ns 8 tooth trigger wheel. Possible alternative.
The Gr/Gl (PG) sensors on the backend of the right cylinder head was mentioned in the Megasquirt manual. Single tooth that will apparently work, but a change to a 12 tooth trigger in place of is recommended.
There is discussion regarding the OEM injectors for the '85 LTD. I had mine cleaned and the flow results came in at 65 ml/min after cleaning. The numbers before cleaning were 64 ml/min. Pressure setting for injector test(s) was 40 PSI. The injector resistance reading was 2.6 ohms for each. The original Honda OEM injectors are quite robust. These injectors are being used in several projects and I have been taking notes regarding the injector impact on tuning the EFI system.
The fuel pump requirement is for 630 cc/min minimum. Static pressure is 34-38 PSI and dynamic 28-34. My system came in at 38 PSI static, and 36 PSI dynamic. When I was searching for the reason I had a fuel/oil smell on start, I pressurized the fuel system and let it sit. Pressure dropped 12 PSI in one hour. Think this is a bit excessive so I am looking for a suitable fuel pressure regulating valve that will fit where the original is.
The idle air control system is a passive system that works quite well for its design. The idle air control (IAC) valve is activated by a bi-metallic element (courtesy of socrace). The IAC valve is wired in parallel with the fuel pump - fuel pump on power to IAC valve. It is never fully closed even when cold and not used for a while. The water system hoses connected to the IAC valve are to prevent freeze up in colder climates, other than this requirement, no need to have a water heated valve. The reed valves work quite well and are operated by cylinder vacuum. I replaced the IAC system hoses, but when I installed the air chamber one of the hoses came off the right side reed valve (had to remove air chamber to repair). These reed valves suck a lot of air and the noise is quite loud. If you did not know better, you would think there was a metal on metal issue, I did, But when I investigated using a stethoscope (Long screwdriver) there was no internal metal noises. The Megasquirt literature I have read indicates that this passive IAC system is acceptable.
Here are twp pics of the IAC valve internals. This is when cold:
I mentioned that a hose came off the right side reed valve when I out the air chamber back in. The hose size is approximately 1/2 inch or so. This is a picture of what I found:
I think I've come to the end of my introduction into the Megasquirt world, and the quest for a suitable ECU upgrade/replacement. More to follow.
Cheers