FI Code 26

You have a few options. These options depend on you and your resources. 1. Try someone else's ECU. 2. Run a new wire from the ECU plug to the sensor. On your bike the wire colors are, Black for the Right Sensor, Red and Blue for the Left Sensor. Your code 25 means Left Sensor. I cut the wire about 6 inches back from the Gray 26 pin ECU plug and used an ordinary butt splice to install a new wire. I crimped a female spade connector on the sensor end. With a whole new wire this will only leave the 26 pin ECU plug or the ECU itself. Also, the butt splice provides an excellent test point for your multi-meter. 3. Take it to a dealer. Now, I am sure there are other options. It all depends on you and your wallet.
 
I paid $105 for my ECM on ebay from a wrecked bike. Usually they are about $200 +/-. If you want to ride up here from Wellington sometime, we'll put mine in your bike and see what happens.
 
Thanks for offering to let me try your ECM. Let me know when is a good day and time. If you can PM me we can set something up. My 07 uses the same ECM as your bike so it should work. Alternatively we can put my ECM in your bike and see if the FI light comes on. It shouldn't take long to check since the light is coming on every time the rpm's go over 4k now.
 
This little story may be nearing its end... A very nice person who just happened to have a spare ECU lying around called me today. The PayPal transactions are done. Hopefully by late next week, I will know something. After that I will evaluate whether to keep my beloved ST or go for the '14 FJR. It is all about confidence now.
 
Your report concerning fuel mileage is consistent with what I get. My ST has always been slightly better on fuel than Dad's FJR. When riding in the NC/TN mountains I usually get 50-51 mpg, unless I am riding it very aggressively. Dad's FJR would get 49-50 mpg. Now that we installed the Power Commander on the FJR his mileage has dropped slightly. A worthwhile trade-off. I have made no firm decision yet about getting rid of the ST. Completely out of left field a certain boat came available... Where to spend the money I don't actually have?
 
This is the latest on my ECM problem. On the way back from Alabama my FI light code 25 seemed to be coming on consistently so I thought that would make it easier to diagnois. STgolfer was good enough to let me test my ECM by putting it in his bike. Before swapping the ECM I had to move a Centech fuse box I have mounted on a MCL bracket at the back of the bike. While doing that I checked the mounting of the ECM with pictures in the manual and determined it was mounted backwards. I had probably moved it while adding farkels at some point. The flat side is suppose to be facing the back of the bike. While turning it around I unplugged the gray connector and plugged it back in. The next day while driving to Stgolfers no F1 light and no F1 light came on his bike when my bikes ECM was used. Drove home no FI light. I am beginning to think/hope it could have been some kind of wire strain or bad connection at the ECM plug. Today I decide to test it and go for a longer ride. No problems all morning then on the way back on some slightly bumpy two lane the FI light comes on again. I pull into a gas station pull the passenger seat off and decide to see if unplugging and plugging in the ECM would make any difference. It didn't. One thing I noticed with the bike in neutral and testing it is that the RPM drops about 500 RPM (from about 4,500 to 4,000) just before the FI light comes on. I hadn't really noticed that when riding the bike maybe the momentum of the bike when running makes it less noticable or prevents the RPM's from dropping as much. I have noticed that once the FI light comes on it pretty much keeps doing it for the rest of that days ride no matter how many times the bike is started and restarted . However if it sits overnight it may become intermitent again. At this point I am thinking it could be the ECM but it is probably a bad wire or connector that is being affected by heat and vibration. Alternativly I am thinking it could have something to do with the battery although I replaced the battery before the trip to Barber. On the trip I was not able to use a trickle charger and the FI problem seemed to get progressivly worse. Since I have been home I have been able to use the trickle charger and the FI light has become intermitent again and only comes on for the first time after the bike has been running for a couple of hours. I have seen ECM's affected by low voltage/bad batteries in cars maybe this could be a factor. I am going to leave the bike off the trickle charger and see if I can make the FI light come on right away by by testing it in the morning on the center stand. If it comes on right away it could be the battery. If I connect it to the trickle charger and it doesn't do the same thing the next day then this also would suggest some relationship to the battery not being fully charged. I am also going to test all the wiring connections again and use dielectric grease. If it continues after that then I guess I am going to have to start buying parts such as a new engine subharness.
 
All of your symptoms match exactly with mine. How long did the two of you run the swapped ECU? When I unplug the ECU I effectively cycle the power and reset it. Then it takes some unspecified and inconsistent amount of time before the code shows itself again. BUT... Once the bike and the ECU is hot the fault will stay every time I exceed 3900 RPM. I have replaced the ENTIRE wire from the knock sensor back to the plug. I have swapped the Left and Right knock sensor wires at the ECU plug. No matter what I do the code is always for the right knock sensor. It has to be the ECU or the gray plug. I am betting ECU.
 
The ECM was only run in STgolfers bike for maybe a minute. Just long enough to see if it would trigger the FI light above 4000RPM. I was hoping the light would come on on the way there so it might be more of a valid test, I think the fact that you get the same code when switching the knock sensor wires is probably a good indicator it is the ECM. I may try that in my bike but I would have to do it in a way I could ride the bike for half a day to see if if the light comes on and then check the code. I'm not ready to start cutting the factory wires yet. Maybe do some kind of posilock tap. Also I think I read somewhere the wire used to connect to the knock sensor is shielded although I don't remember it looking that way.
 
The factory wire does have an uninsulated shield. I did not go back with a shielded wire, I opted for a high temp insulation instead. The ONLY reason I cut the wires to begin with was that the Genuine Honda Service Manual was WRONG!!! and I was testing the wrong wire at the ECU plug. This caused me to diagnose the wire as Bad (no continuity) between the sensor and the ECU. Of course, this also meant I cut the wrong wire. Before I was done, I had cut both wires to run a new wire... Curses to Honda for their mistake in the manual! Your idea for the posilock tap is a good one. I think that you are going to wind up with a new ECU.
 
Redfish, thanks for you suggestions. Hopefully your replacement ECU will arrive shortly and this problem will be resolved. I'll probably keep an eye out for one at a good price. In the meantime I will do a few more diagnostics such as trying to switch the knock sensor leads and see if the code changes. I'm sure eventually it will get sorted out. Its just a matter of trying to get it done without spending to much time or money on it.
 
Winston Lee asked a good question that I thought was worthy of its own thread, so I moved it here: CLICKY

--Mark
 
After working all night on the ride home I ran a lower gear to get my RPMs above 3900. Within 8 seconds I had my Red FI light. Wife had new to me ECU on kitchen table waiting for me at 4:45 am. Quickly installed. Ran bike. Ran bike some more. NO CODE. Will ride more before work this afternoon. I think I (we) got it.
 
Good to hear, glad a forum member was able to help you out.
 
One of our very own st-owners members came to my rescue on this one. This man PM'ed me and made me a wonderful deal knowing that I was over a barrel and would be forced to pay almost any price. Out of respect for this gentleman I will not reveal his "identity" unless he does so himself. I will say that I slept much better with the knowledge that Ole Blue was running properly. Oh, it is true by the way. You meet the nicest people on a Honda...


Edit: Ran as much as I could above 4000 RPMs this afternoon. Never saw that Red FI light. Never not once. I kept cringing, expecting that power dip and that hateful flash of red from the dash, but it never happened. Feeling better all the time.
 
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I'm not sure if you could easily tell if the ECU is potted or not but it would be interesting to do a post mortem on it if it could be opened up.

Guess this means that you can put off acquiring that FJR for awhile...
 
Scooter said:
I'm not sure if you could easily tell if the ECU is potted or not but it would be interesting to do a post mortem on it if it could be opened up.

Guess this means that you can put off acquiring that FJR for awhile...
Click to expand...

I am so bitter about the whole thing that I have considered using the old ECU for target practice.

You are correct (I hope!) in that I may not have to replace the ST with a new FJR. If that new red color looks good enough, I may have to do it anyway. I sure enjoyed riding the ST to work this evening though. I could rev it past 3900 without that sickening stumble and that ugly red light.
 
Redfish I'm glad you can get back to enjoying your bike. I remember somebody posting that the mechanic at the dealership told him that 9 times out of 10 it is the ECU. Looks like he is right based on your experience and some of the other threads on knock sensor codes.
 
Since I was just reading another thread on this very issue I thought I would give this thread a bump and an update. I have had zero issues with the ECU. I have not seen any FI codes. The bike is running beautifully and it has been getting a (very) few miles.
 
I'm a little confused here. I've seen posts on this forum and a "Manual correction" posted in ST-Wiki that suggest the Honda SM has the knock sensors associated with the failure codes 25 & 26 reversed. However, someone who unplugged a sensor lead to see which code was displayed verified the manual is correct in that respect, although one or two of the troubleshooting procedures and the wire colors described in the manual are apparently incorrect. https://www.st-owners.com/forums/showthread.php?43161-FI-Issues-(Code-25)/page2
Wire colors should be easy enough to check - the wire at the sensor should be color coded the same as the wire at the ECM connector, unless a color coding switcheroo occurs at the 10-pin connector between the lower sub harness andthe harness connected to the ECM. :confused:
I would like to be able to troubleshoot and correct the problem by removing tupperware from just one side, so it would be nice to know which side before I start.
 
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