Things to Check on ST1300 for FI Light Code 26

On to the next snag. I was testing the knock sensors per the FSM and when I inserted the multimeter probe into the right connector, the blue plastic in the connector just crumbled. There is also some bare wire showing. See the pics below. The good news is that this could be the cause of the code 26. Any idea where I can get a connector to splice in? I looked on the parts fiche and noticed SUB-WIRE, ENGINE - #9 under Crankcase (part number 32109-MCS-700) but I'm not sure if that's the right part or how hard it would be to install. Has anybody ever replaced one of these? It would be the best option if it's not too difficult.

Here's a picture of the left connector which is still okay:


Here's the right connector how it is currently followed by the broken pieces of blue plastic.

 
I was able to get a new sub harness and was planning to replace the existing one that has the bad right knock sensor connector. I had the knock sensors, engine oil pressure, engine coolant temp, engine coolant temp ground, and neutral switch connectors all off. Disconnecting these requires removing the thermostat housing (replaced the thermostat and o-ring while I was in there). I had trouble disconnecting the 10-pin gray connector. It’s very difficult to get off because there are two levers to squeeze to remove it at different angles, plus the access is very limited. I could see that I was getting close to damaging the connector that would remain on the bike, and after what I experienced with the knock sensor connector crumbling, I decided to punt. I ended up cutting the knock sensor connector off the new harness and splicing it into the old harness. I really hated damaging a brand new harness, but if I damaged the 10-pin connector, it could be catastrophic and possibly the end of the road for my 1300. I’m hopeful that this will correct the FI light/code 26 issue, but not sure yet. If it does, I may replace the sub harness in the future if I ever have the throttle body out for other reasons. The only thing left on my winter maintenance is brake and clutch fluid service. Then I can put the plastic back on and take it for a ride to see if the light comes back on. I think I’ll be able to tell without riding it too hard by the mpg reading which is normally around 42-43, but pinned at 40 while having this issue.
 
RobbieAG said:
.... take it for a ride to see if the light comes back on. ......
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You can also just rev it up over 4200 RPM for a short while for a first quick check.....but if the light doesn't come on then, no guarantee it won't light up later on a longer ride over 4200 RPM.
 
Just reading through this for the first time. Glad you got the screw out.

@RobbieAG - The part number you posted for the hex head screw seems to be the number for the JIS screw rather than ne with a hex head. But on the RonAyers and partzilla site for the PA model, that part number is still quoted. ie 91508 mgp d00

The screw is a special one with a built in shoulder to prevent tightening onto the plastic.

Were you able to find these with the hex head please ? I want some for the next time I take off the funnel bases - I usually order a brand new JIS driver for each time I remove those screws !
 
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jfheath said:
The screw is a special one with a built in shoulder to prevent tightening onto the plastic.

Were you able to find these with the hex head please ? I want some for the next time I take off the funnel bases - I usually order a brand new JIS driver for each time remove those screws !
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You can always use a piece of tubing as a spacer.
 
jfheath said:
@RobbieAG - The part number you posted for the hex head screw seems to be the number for the JIS screw rather than ne with a hex head. But on the RonAyers and partzilla site for the PA model, that part number is still quoted. ie 91508 mgp d00

Were you able to find these with the hex head please ? I want some for the next time I take off the funnel bases - I usually order a brand new JIS driver for each time I remove those screws !
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Yes, I was able to get the hex head screws (91508-MGP-D00) from the 2015 police model and installed them. The part number for the JIS head ones I'm showing for my 2005 model is 91508-MM5-000. I got one spare one of those just in case the others didn't work but they did, so this should never happen again.
 
Great news! I finished the brake and clutch fluid service, put the bike back together and took it for a ride. It was only about 15 miles, but I made sure to keep the revs over 4200 for a significant amount of time. So far, no FI light and the mpg average has also returned to normal rather than being stuck around 40 mpg. I realize, the FI light may return, but for now I’m calling it fixed. I feel very relieved that my bike is back to normal. Just goes to show you shouldn’t assume it’s a bad ECU without checking everything else first.

For those who haven’t followed the thread – a summary. I started seeing the FI light on with code 26 during this year’s Blue Ridge Gathering (after owning the bike for 8 years). I was worried that it would be the ECU but first checked everything on my list (on the first post of this thread). It turned out to be a bad connector to the right knock sensor. I fixed it by purchasing a new engine sub harness (around $55), cutting off the connector and splicing it onto the old harness.
 
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Great news!
I've repaired 3 bikes with the dreaded FI code 26 flashing....without replacing the ECU.
Too many folks turn to You tube, or various forums, and are told you must replace the ECU to correct this.
This may not be the case. I've replaced 3 sub harnesses and damaged switches due to heat issues, that corrected the problem for about $50 dollars.
Two of the people purchased ECU's only to find they still had the issue.
After the sub wire harness was replaced, none of them have reported back that their FI light has returned.

Find the cause of failure, instead of throwing solutions at a problem.
:WCP1:
 
Mellow said:
But you're replacing a part to fix it... :rofl1:
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Yes, the correct one part, after you know which is bad. Troubleshooting is a process of elimination.

Added: As an example from a new post: "I changed coils, plug wires, fuel pump, gas filter, fuel pressure regulator, temp sensor and other stuff but the final fix was the crank position sensor."
 
Larry Fine said:
Yes, the correct one part, after you know which is bad. Troubleshooting is a process of elimination.

Added: As an example from a new post: "I changed coils, plug wires, fuel pump, gas filter, fuel pressure regulator, temp sensor and other stuff but the final fix was the crank position sensor."
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That sounds like a Genuine Honda Service Department trouble shooting guide :rofl1:
 
I rode the bike to Ga-STOC last week and the FI light is back (code 26). I confirmed that my connection is still good and it's throwing the same code, so I have to conclude it's the ECM. I'll be on the lookout for a good used one if I can find one. There were no noticeable issues with riding the bike with the light on other than marginally reduced fuel economy. I'm disappointed, but it won't strand you so that's a plus.
 
Robbie, to eliminate possibilities, can you swap sensors, or the sub-harnesses (if they match)?
 
Larry Fine said:
Robbie, to eliminate possibilities, can you swap sensors, or the sub-harnesses (if they match)?
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Yes, I realized that's the only thing on my original list that I didn't do. When I found the bad connector, I figured that had to be it. I'll swap them next time I have the plastics off and hope for the best.
 
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