FI code 26

I haven't yet figured out how vacuum hoses or the five way T could possibly have anything to do with a FI code 25 or 26, maybe one of our digital tech gurus can explain it to everyones satisfaction. If the failure is totally unrelated to wiring or a failed sensor, seems to me that might point to a failed ECU throwing an erroneous code, but that wouldn't explain the 4k rpm threshold.:confused:
 
I'm of the opinion that while the codes do reflect particular FI issues, I don't believe they are exclusive. That is to say if the knock sensors, ECU and associated wiring have all been replaced and code 26 still comes up then there's every reason to suspect that something else is amiss.


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Igofar said:
Had a bike in the garage this week with the same FI code thrown. Pulled the lines & tee, replaced with new and did a TB (starter valve sync) just for good measure, cleared codes, life is good again, no more FI codes thrown.
Click to expand...

How many hard high RPM miles (not just garage blips) without codes since the Tee clean up?
 
About 200 miles round trip, blasting down the Pacific Coast Highway, and several little twisty mountain roads, along with a couple hours of freeway mixed in, why? :rolleyes:
 
Perhaps the clogged lines/tee were causing the ECU to throw an erroneous code?
I'd love to hear what our digital tech gurus have to say as well.
:bigpop:
 
So it's been awhile since posting on this thread. I've done several things with the constant help of Larry "Igofar". When I last posted I was going to clean the 5 way tee and replace the tubing to/from. Here's the current list of attempts.
- replaced the right knock sensor connector. Still got the code 26.
- swapped the ECU with a used one. Still got the code 26. I did get 235 miles out of the borrowed one though. The borrowed ECU has not been confirmed as good. Reinstalled original ECU.
- swapped the knock sensor from left to right and right to left. Still got the code 26.
- cleaned the tee and replaced the tubing. New air filter. Still got the code 26.
- replaced the plugs to Denso U24FER9's. Still got the code 26. Did this because I had changed my plugs to Iridium NGK CR8EHIX-9 two weeks before the trip to ArkanSToc. Thought there might have been a chance there. No such luck.
- earlier this week I went deep and replaced the engine sub-wire assembly (32109-MCS-700). Big job that took many hours and cuss words which also included coolant flush & fill. Got the code 26 again today. The current ECU is also not down in the pocket that it sits in. It's sitting horizontal under the passenger set to see if taking pressure off of the wires would make a difference. It didn't.

The one last thing I've got on the schedule for this coming week is to do a throttle body sync. I've ordered a Carbtune but I don't know when that will be here so I'm heading to see Vinny and see where that leaves me.

I am stumped, beat down, broken, pissed off, annoyed and many other adjectives. Not really sure what to do after the upcoming sync if that doesn't do it. I'm seriously thinking about taking it a dealer to see if they might be able to do an ECM test with the dual test harnesses they mention in the service manual. Who knows!

Skip
 
I own a ST1100 but I have a ST1300 ( 2003-2006) Service Manual.

So, in the ST1300 manual, the schematic shows one wire going to the knock sensor, and a ground connection. So the knock sensor ground connection is through the engine block.

What shape is the ground strap connection going to the engine ? Any corrosion ? You could add an extra ground wire from the frame to a bolt near the knock sensor to make sure you have a good ground at the knock sensor.

Also, do the connections at the ECM connector for the knock sensor seem OK ? It's either the Red/Blue or Black wire.
 
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skipcurt said:
I'm seriously thinking about taking it a dealer to see if they might be able to do an ECM test with the dual test harnesses they mention in the service manual. Who knows!

Skip
Click to expand...

Never heard of anybody having any luck finding this test harness here in the US. Have seen it advertised on European sites before, north of 1000 Euro!

Closest you might be able to find for testing your ECU is Carmo in Holland (Carmo.nl) per this post.
 
Jim Van said:
So the knock sensor ground connection is through the engine block.
What shape is the ground strap connection going to the engine ? Any corrosion ? You could add an extra ground wire from the frame to a bolt near the knock sensor to make sure you have a good ground at the knock sensor.
Also, do the connections at the ECM connector for the knock sensor seem OK ? It's either the Red/Blue or Black wire.
Click to expand...
I am unfamiliar with the ground strap. Can someone tell me where that is and I will certainly check it. Very early on in this thread I did some electrical testing (not my strong area) with help from others here and the tests did return that the wiring was good. Assuming I did them correctly. I probably should revisit those tests. The immediate wiring from the ECM does appear fine. That was one of the reasons for moving the unit up out of the pocket and sitting it horizontal to take any potential pressure off of the connectors going into the ECM. I had the borrowed ECM in this position when I had the best result of 235 miles without the FI light coming on.

Skip
 
Just look around the engine block & trans. It will be a fairly large diameter wire that is connected between the frame & block, maybe on the back of the trans (?). Since the block is aluminum and the connector is not, corrosion at that connection can occur. I know Yamaha had a recall on the FJR1300 for a similar problem at the "five-star" ground connection.

EDIT : There is a pic in my ST1300 Service Manual that shows the ground strap is connected at the end of the starter.

Also, it helps when diagnosing an intermittent problems such as yours to wiggle the wires while you are checking for continuity like when you did the continuity check from the knock sensor connector to the ECM connector, to try to induce a bad connection, if it may exist. You may need a helper to hold the meter leads while you wiggle the wire going into the knock sensor connector and into the ECM connector. While wiggling the wires, the meter should display a nice steady reading near zero Ohms. Should read about the same as when you touch both meter leads together. In fact, you should read just about the same reading when you Ohm out between the negative battery terminal wire and the engine block.

When you switched the knock sensors, was there much corrosion ( white stuff ) on the threads of the knock sensors ?

Jim V. ( old electronics tech )
 
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Jim Van said:
EDIT : There is a pic in my ST1300 Service Manual that shows the ground strap is connected at the end of the starter.

Also, it helps when diagnosing an intermittent problems such as yours to wiggle the wires while you are checking for continuity like when you did the continuity check from the knock sensor connector to the ECM connector, to try to induce a bad connection, if it may exist. You may need a helper to hold the meter leads while you wiggle the wire going into the knock sensor connector and into the ECM connector. While wiggling the wires, the meter should display a nice steady reading near zero Ohms. Should read about the same as when you touch both meter leads together. In fact, you should read just about the same reading when you Ohm out between the negative battery terminal wire and the engine block.

When you switched the knock sensors, was there much corrosion ( white stuff ) on the threads of the knock sensors ?

Jim V. ( old electronics tech )
Click to expand...
I will look into the ground strap this week Jim. When I get up to Vinny's garage I'll see if we can get two hands on each end of the wiring and see what we come up with. I did not see any corrosion when the sensors were removed.

Skip
 
So the latest update is that the throttle body sync was unsuccessful. We also cleaned the battery contacts including the connections. We could not access the ground strap by touch or sight without getting into major part removal so it is unchecked.

Today I bit the bullet and sent her to Southern Motorsports in Chattanooga for diagnostic check and hopefully repair. They are highly recommended by several people I've spoken to so I'm hoping for the best. I gave them a detailed list of actions performed with dates and mileage since September when this all started. They were very accommodating and polite, didn't talk down to me and I left feeling comfortable with them but sad that I had to leave her behind. This is the first time she's been to dealer for work since I took possession on '09 and 70k miles. I'm hoping for the best and hoping not to break the bank on this one. So please, no dealer bashing or comments about whether you'd visit a dealer or not. I feel like I've given it my best to try and solve the problem but I want it fixed so I can get back to normal riding with full confidence in my ST.

I'll let you know the outcome.

Skip
 
You've given it a serious effort to be sure.

From the number number of folks who have had an unsolvable code 25/26 issue it would be great to get another viewpoint.

I hope they find something quickly and without spending a kings ransom.


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I have unsuccessfully tried to fix a f25 code. Mine will go for along time without showing up then will go off 4 or 5 times in a day. I haven't found what causes it. Real anxious to hear what you find to be the problem.
 
UPDATE:
I have finally picked up my beloved ST1300. In fact it was last Saturday I went and picked her back up from the dealer after being there for 7 wks. Sure seemed like forever! Over those weeks I've endured countless phone calls back and forth only to have it pushed back another week and another week due to holidays, vacations, illness and wintry weather.
After being there for two weeks they finally got to my ride and they said Mother Honda said to replace the knock sensors and ECU with more emphasis on the ECU. I told them to start with the sensors (because it was the cheaper of the two) and see where that brings us. That didn't fix it.
Next was the ECU. They quoted me $1046 for a brand new unit. I had done a little internet shopping and came up with a brand new one for $721 and of all places it was at the same dealer where my bike was. In the end they sold it to me for the internet price. I think the guy was a bit embarrassed. So, they replace the ECU and end up having to wait about a week because they can't get it out to test ride due to rain, snow, ice and/or cold weather. They finally give the green light to come and pick it up last Saturday and I did but I don't have any time in my schedule to test ride her myself until Wednesday. I go out for an 80 mile ride and the light never came on and seemed to run well. Today I will say that it is fixed but I do really feel like I need a nice all day ride to put her through the paces of a real test. Hopefully very soon.

It kind of ticks me off because I swapped the ECU with a loaner and still got the code. Granted the loaner was never verified as good but later down the road, Stan said he tested it on his bike and never got the light. Completely baffles me.

Anyhow, I'll post back with the results of my next all day ride. Thank you, thank you, thank you to all who have helped and contributed to this thread. I hope that down the road it may help someone else out.

Skip
 
So glad to hear that the problem is solved albeit in a somewhat frustrating way.

Maybe it was the combo of new sensors and new ECU that made the difference.


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There is a guy in the Montréal area to whom local garages send automobile ECM's for repair. My brother-in-law just got his ECM back from there after it his truck would not start. It runs fine now. Based on the damage he found inside the ECM he told the garage to look for a bad ground connection because this is what caused the damage and he was right- the main ground harness between the body and the engine was rotted out.

So my question is- has anyone taken the ST1300 ECU to a shop that repairs these computers for the automobile industry to see if they can fix it? I can't see there being any mysterious difference between an automobile ECM and a motorcycle ECU. I would be curious to see what they would say.
 
Andrew Shadow said:
There is a guy in the Montréal area to whom local garages send automobile ECM's for repair. My brother-in-law just got his ECM back from there after it his truck would not start. It runs fine now. Based on the damage he found inside the ECM he told the garage to look for a bad ground connection because this is what caused the damage and he was right- the main ground harness between the body and the engine was rotted out.

So my question is- has anyone taken the ST1300 ECU to a shop that repairs these computers for the automobile industry to see if they can fix it? I can't see there being any mysterious difference between an automobile ECM and a motorcycle ECU. I would be curious to see what they would say.
Click to expand...

I have not but I was able to get the old ECU to bring home.
 
As a thought !, with my 2 pence through in. From what i have read, The knock sensors may have had an issue , by which the sensors may have broken down inside , causing Fluctuations in voltages & currents which feedback to the ECU ( say a grounding fault,etc.) which can prematurely cause breakdown in contacts ,issues and failures inside the ECU. I have had something similar this before with my VW Passat ECU.

Glad to here you fixed it and fingers crossed it lasts for you.

regards

Tony
 
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