ST1300 ECU-Knock sensor problem

[Truman]

Apparently this problem is very common on ST1300 models '07 and earlier. I have not seen or heard of it on the later models, '08 and up. Looks like Honda changed the '08 ECM which solved the problem, but did nothing to address the problem with the ECM in the earlier models. Has anyone questioned Mother Honda about this?

I tried to call Honda and complain about this but kept hitting the customer NO service guy in California. he had no clue about what I was talking about. If everybody on this thread will go the the BBB and file a complaint we might get their attention. It's gona take more that one or two.

 

[Ricardo Sim~es]

Hi everyone. Well, I´ve read that a bad knock sensor can damage a ECM because of the higher voltage produced. Later I´m going to test both of mine sensors and post here the results, with a osciloscope.

Regards

 

[bstig60]

Try writing a nasty review and description of the situation on Honda's Motorcycle Facebook Page. That will definitely get someone's attention as they don't like bad publicity.

Hi everyone. Well, I´ve read that a bad knock sensor can damage an ECM because of the higher voltage produced. Later I´m going to test both of mine sensors and post here the results, with an oscilloscope.

Regards

There are two problems I have seen with the left knock sensor FI code. The first is the sub-harness wiring getting toasted by the heat of the exhaust; the other is an ECM failure causing the code 25 or 26. I had both on my '07. Wiring was repaired and the bike ran about 100 miles before the code came back, according to the PO. I verified the wiring on the sub-harness on both knock sensors all the way back to the ECM. My bike came with a new knock sensor and a new sub-harness which I still have but never installed. I managed to get an ECM from a 2003 bike for a reasonable price, replaced it and the problem went away, that was almost 7000 miles ago. So far, so good.

 

[T_C]

I'v ebeen running good for months since mine showed the code. This morning, it was back. Cycle power, pop the clutch and it went away. Now I was averaging 5k rpm, for quite awhile, so maybe I am actually a victim of the Rostra pulse divider. Hmmm...

 

[tjhiggin]

I did an 85-mile ride yesterday. For 70 miles of highways and country roads, I tried every which way to make that FI light come on. It would not. Thinking victory was in hand, I hit another highway for the 15-mile jaunt home. Wouldn't you know, after a couple of miles at 70 mph, the durn light came on. I was running late for a family function so did not get the code. I'll take another ride in a day or two and get the code.

awaiting the code....bet I will be a 25

Rode bike to work today, 27 mile commute. 41 degrees F, a little nippy!
FI light came on just a few miles after leaving the house. Truman, you are correct. Code 26 with my ECM, code 25 with your old one. A new ECM is in my future, too.

 

[Ricardo Sim~es]

Hello Ricardo, welcome to the ST-owners forum.
Best of luck with your electrical gremlin.

Thanks!!

 

[bstig60]

Rode bike to work today, 27 mile commute. 41 degrees F, a little nippy!
FI light came on just a few miles after leaving the house. Truman, you are correct. Code 26 with my ECM, code 25 with your old one. A new ECM is in my future, too.

Keep checking on eBay for a good used one. They are half or less the price of a new one. This fits 2003-2007. https://www.partzilla.com/product/honda/38770-MCS-L01?ref=585bf39243e9f203eed1ba9765d875f6511b7928

 

[Truman]

Rode bike to work today, 27 mile commute. 41 degrees F, a little nippy!
FI light came on just a few miles after leaving the house. Truman, you are correct. Code 26 with my ECM, code 25 with your old one. A new ECM is in my future, too.

So you're saying you got a 25 with the one i sent you ? Hummm very interesting. if your in the mood one day look on the left side and tell me what color wire in coming from the left side sensor. It should be blue with a red stripe. at lease thats what mine was. The right side was a solid blue. some of the st's were wired backwards just wondering

 

[CKing]

Part of it is fuel mileage and performance, other part is if ignoring F1 light what other warnings are we ignoring that that light may be trying to tell us.

If you ride it long enough, it may start misfiring and lose power. Mine did, and we barely got home.
Had to replace the ECM and spark plugs.

 

[CKing]

Just reading through this post. I can't pretend to have any experience of the knock sensor problem, but I'm intrigued.

In the first post, you say that the wiring harness has been repaired and the fault is with the ECU. Can I ask what made you come to that conclusion ? If I had a bike that had an obvious 'repair' in the wiring harness, I'd be looking at the repair for the source of the fault !
Is the engine actually knocking ? (some people call it 'pinking' in the UK) ? If so when ? On earlier bikes it was common to have them pink when hot and under load at speed.
Having done the usual tests I assume that you have the shop manual ? PM me if not. .
I have a note that I wrote in my workshop manual which suggests that the codes for 25 and 26 are the wrong way round. I didn't delve any further into this - just added the note from something that I read. I assume that you have read this post and comments from nckingz1300 Link. He's in Aberdeen with an 04 that showed a similiar fault.
Mark (Brfl) put a link on that post which suggests that the fault codes for 25 and 26 are reversed - but there are different versions of the manual so care might be needed in reading this.

John

The shop manual is reversed, the wiring colors are incorrect, and at the end of diagnostic check, it says "install a known good ECM". Good luck with that.
Note: I did find overheating on the right knock sensor. Replaced with connectors from Honda automotive.

 

[Ricardo Sim~es]

Hello everyone. Well, I did a check with a osciloscope and find out that the right sensor doesn´t "answer" with the same voltage of the left. You can see on the image the diference between. To ensure that is the sensor that is damaged, I´m going to switch both and test again.

The bad sensor is indicated as blue colour.

Regards everyone.

 

[bstig60]

Did you check this at the ECM or at the sensor?

 

[Ricardo Sim~es]

I've checked on the Grey conector.

 

[2xthefun]

I have the same issue living in Florida. My question is i read that the some people bought used ECM. How come all those bikes still running perfectly {no red light}? All those ECM-s come off a bike. Our bike-s just dont like the ECM they came with originally?

 

[bstig60]

I have the same issue living in Florida. My question is I read that some people bought used ECM. How come all those bikes still running perfectly {no red light}? All those ECM-s come off a bike. Our bikes just don't like the ECM they came with originally?

Some of the ECM's develop a fault and throw a code 25 or 26. If you check the wiring and it is OK, then most likely a known good ECM is the cure. It was with mine and with many others. Many have also had issues with the wiring for the right sensor overheating as it was too close to the exhaust. This will give the same FI code. I had both problems. The wiring was repaired and the ECM replaced with a used one.

 

[2xthefun]

Some of the ECM's develop a fault and throw a code 25 or 26. If you check the wiring and it is OK, then most likely a known good ECM is the cure. It was with mine and with many others. Many have also had issues with the wiring for the right sensor overheating as it was too close to the exhaust. This will give the same FI code. I had both problems. The wiring was repaired and the ECM replaced with a used one.

Thank You !

 

[Gus1300]

To ensure that is the sensor that is damaged, I´m going to switch both and test again.

Ricardo, how did your swapped test pan out? Still see the difference? I'm going to dig into my Code 25 this winter (two knock sensors on the shelf) and hope it's not the ECM but so far it's not looking promising! In the meantime, under 4k RPM keeps the light off, and the chance for a performance award minimal.

 

[leonides]

Let me intrude and aport some info on this matter.
When I first have the FI light on it shows code 26.
I reach to the left sensor, tested and it was OK, then I switch left to right and vice versa. Check all the electric cables etc.
The light was off for about 300 miles until I reach 80 mph. Following the tips from Igofar I reset the ECU. I was happy for another 200 miles until I reach 90 mph.
I had the code 26 again.
So my solution will be a pain to the pocket: new ECU.
Best price at Partzila.
Good luck.

 

[bstig60]

Let me intrude and aport some info on this matter.
When I first have the FI light on it shows code 26.
I reach to the left sensor, tested and it was OK, then I switch left to right and vice versa. Check all the electric cables etc.
The light was off for about 300 miles until I reach 80 mph. Following the tips from Igofar I reset the ECU. I was happy for another 200 miles until I reach 90 mph.
I had the code 26 again.
So my solution will be a pain to the pocket: new ECU.
Best price at Partzila.
Good luck.

Keep an eye on EBay for a good used one.

 

[leonides]

Keep an eye on EBay for a good used one.

Yes, you can find some at a very good price, but they are not going to offer you any warranty on it, and you may inherit a new problem from the former owner.
thanks for the advice.
P.B.