Ignition Problem?

Thanks for the list, that helps to think about the problem without having to read 330 posts. I can say that you have been very thorough and it seems impossible to think of anything that you may have missed. I can say that you have had some excellent help. You deserve a rest and a prize for all that you have gone through. :yr1:
 
wjbertrand said:
Decided to post an updated liST of attempted repairs:
Click to expand...

Thanks for posting the LIST of attempted repairs, it helps us with troubleshooting knowing what you've done or tried.
Now for the $64,000 dollar question...I think I may know what is wrong with your bike!!!
My bike did the EXACT same thing, at the EXACT same RPM, and the TAC dropped momentarily, and the engine was cut off for a moment (lights and stuff remained on).
This is the part you may need to order.
Honda - 37700-MCS-003
Its a ten minute repair, and I didn't see it anywhere on your list.
Larry
 
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Wish I had an answer to that one myself, and just like everyone else, I have no idea why its throwing the codes its throwing. All I do know is when my speed sensor starting failing, I was running down the freeway, far from home, at a steady 4000 rpm, when the engine power turned off like a light switch for just a brief second, and during that time the needle on the Tach fell to zero, then bounced back up, then all was normal again. My bike started fine, and ran good until I hit that area in the RPM range, and it stumbled a couple more times before I got home. Something failing in the speed sensor switch was causing the bike to shut down and misfire or cut out (engine, not lights). The replacement is pretty straight forward, and pretty cheap as I remember. Simply remove the right side cover, and hidden behind the smog canister is the group of connectors in a plastic sheath, one of them is to the speed sensor. Simply unplug it, tie a string to it, then go underneath the bike and remove two 8 mm head screws, the switch, and O-ring. A small amount of oil will drain out, but a pie pan was more than enough to catch it. Pull the sensor straight out the back, until you reach the string, then place the string on the new connector and pull it back through and plug it back in. Install the new switch, and plug it in. That's pretty much all there is to it.
I've seen a few of these fail over the last couple years.
This would be the next thing that I would check.
Igofar
 
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Igofar said:
Thanks for posting the LIST of attempted repairs, it helps us with troubleshooting knowing what you've done or tried.
Now for the $64,000 dollar question...I think I may know what is wrong with your bike!!!
My bike did the EXACT same thing, at the EXACT same RPM, and the TAC dropped momentarily, and the electrical stuff was cut off for a moment.
This is the part you may need to order.
Honda - 37700-MCS-003
Its a ten minute repair, and I didn't see it anywhere on your list.
Larry
Click to expand...


Your right, I have not replaced this. One difference to your symptoms is that I do not have any other electrical interruption, lights, sound system, instruments, speedometer, etc. do not cut out, only the wavering tach needle during misfire episodes. I did remove the speedohealer to no effect.
 
Igofar said:
Thanks for posting the LIST of attempted repairs, it helps us with troubleshooting knowing what you've done or tried.
Now for the $64,000 dollar question...I think I may know what is wrong with your bike!!!
My bike did the EXACT same thing, at the EXACT same RPM, and the TAC dropped momentarily, and the electrical stuff was cut off for a moment.
This is the part you may need to order.
Honda - 37700-MCS-003
Its a ten minute repair, and I didn't see it anywhere on your list.
Larry
Click to expand...
Larry just one more question. What led you to the VSS when your bike had the symptoms?
 
My lights, instruments and speedometer did not fail either, the bike cut out (engine stopped running) for a split second and the the tachometer needle dropped to zero, then everything instantly came back on, and the tachometer bounced back up to where it was at 4000-4200 RPM. Even though I lost ENGINE power for a split second, and the Tachometer needle dropped, I did not loose any instrument lights, headlight, etc.
I really think this is something you should check.
 
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woodybelle said:
Larry just one more question. What led you to the VSS when your bike had the symptoms?
Click to expand...

Was curious why my Tachometer needle would instantly drop and my power was cut off in that area at the same time, and started troubleshooting the symptoms.
 
wjbertrand said:
Your right, I have not replaced this. One difference to your symptoms is that I do not have any other electrical interruption, lights, sound system, instruments, speedometer, etc. do not cut out, only the wavering tach needle during misfire episodes. I did remove the speedohealer to no effect.
Click to expand...

Neither did I. Even more reason to believe this may be your electrical issue.
 
It only takes a few minutes to replace, perhaps you could find another ST rider and swap out his part for a short test ride, or maybe pick up a used one at a salvage yard to try?
 
Igofar said:
Wish I had an answer to that one myself, and just like everyone else, I have no idea why its throwing the codes its throwing. All I do know is when my speed sensor starting failing, I was running down the freeway, far from home, at a steady 4000 rpm, when the engine power turned off like a light switch for just a brief second, and during that time the needle on the Tach fell to zero, then bounced back up, then all was normal again. My bike started fine, and ran good until I hit that area in the RPM range, and it stumbled a couple more times before I got home. Something failing in the speed sensor switch was causing the bike to shut down and misfire or cut out (engine, not lights). The replacement is pretty straight forward, and pretty cheap as I remember. Simply remove the right side cover, and hidden behind the smog canister is the group of connectors in a plastic sheath, one of them is to the speed sensor. Simply unplug it, tie a string to it, then go underneath the bike and remove two 8 mm head screws, the switch, and O-ring. A small amount of oil will drain out, but a pie pan was more than enough to catch it. Pull the sensor straight out the back, until you reach the string, then place the string on the new connector and pull it back through and plug it back in. Install the new switch, and plug it in. That's pretty much all there is to it.
I've seen a few of these fail over the last couple years.
This would be the next thing that I would check.
Igofar
Click to expand...


Did you notice that the engine would operate normally at that RPM when it was still warming up or if the throttle were opened more?. Mine will stop acting up the moment I apply additional throttle. I suppose its possible the ECM is changing maps based on RPM and speed??

The part isn't all that cheap, best price I've found is for a new one at ~$75. No used ones on ebay right now. Has anyone got a spare they could loan me? I wouldn't mind spending the money if I can prove this is the culprit, but the spousal unit is becoming less tolerant of the "experimentation" expenses (she wants a new kitchen).
 
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As far as warming up, I can't answer that question, as I always let the bike warm up to three bars before taking off. I don't recall having any issue with it while warming up. However, when it happened to my bike, I was running down hwy 101 around 75-80 mph, at steady throttle, and the bike stumbled and cut out. The moment it happened, I instinctively cranked the throttle open, which brought everything back again. The next couple times it happened, if I remember correctly, was when I was rolling the throttle off or slowing down (off ramp / approaching stop ) and again, applying throttle brought everything back, so yes, the problem stopped acting up when I applied more throttle.
 
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wjbertrand said:
Did you notice that the engine would operate normally at that RPM when it was still warming up or if the throttle were opened more?. Mine will stop acting up the moment I apply additional throttle. I suppose its possible the ECM is changing maps based on RPM and speed??

The part isn't all that cheap, best price I've found is for a new one at ~$75. No used ones on ebay right now. Has anyone got a spare they could loan me? I wouldn't mind spending the money if I can prove this is the culprit, but the spousal unit is becoming less tolerant of the "experimentation" expenses (she wants a new kitchen).
Click to expand...

You may want to reach out to Bob (SupraSabre) on the forum, he has a bunch of spare parts bikes and he may be able to assist you, and he may not be that far away from you.
Perhaps if you offered to pay shipping etc. he may load you one if he has it.
 
Igofar said:
You may want to reach out to Bob (SupraSabre) on the forum, he has a bunch of spare parts bikes and he may be able to assist you, and he may not be that far away from you.
Perhaps if you offered to pay shipping etc. he may load you one if he has it.
Click to expand...

Beat you to it, I've already asked him. Bob lent me a second ECM to test that was from a 2005, just in case the one I borrowed from a 2004 earlier was somehow not compatible. Another thought is that I can replicate the cutting out problem just revving the engine in neutral with the bike on the stand. The speed sensor wouldn't be functioning or sending any kind of signal with the bike completely stopped would it? Did you have a malfunction code / FI light in your case? I may have found a used VSS on ebay just searching "ST1300 sensor". Evidently the seller doesn't know what it is but I think it's a speed sensor because I know what all the other sensors look like at this point and this one doesn't look familiar to me. Does this look like an ST1300 VSS to you?

https://www.ebay.com/itm/2006-03-15...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
 
Yes, that looks like a speed sensor switch, and it even has the o-ring that is needed, however, I don't trust used electrical parts. How do you know that this isn't the broken one that he replaced?
You didn't say if Bob was going to send you a spare switch to try?
As far as replicating it by revving the engine in neutral, I don't think that would be a valid test if the switch were cracked or broken inside. Maybe the speed sensor wouldn't have to send any kind of signal if it were damaged, maybe the damage itself is sending a signal?
I do remember that my bike threw a code, but can't honestly say I remember what it was at this point.
 
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