Ignition Problem?

[bdalameda]

I have seen many cases where trouble codes are not generated by a faulty sensor especially the ignition pulse generator (ignitor by some). Have you checked the sensors with a good multimeter? I believe the meter readings are shown in the maintenance manual.

 

[Tech]

AD's recap & analysis is an excellent starting point. Vibration...a specific frequency @ 4250 rpm..... is a possible cause. It could be tripping a faulty relay.

I have experienced sensors on my 05 4Runner not activating a trouble code.

Looking at the wiring diagram;

Relays, that may be subject to vibration:

Main Stop, Fuel Cut, Bank Angle

The following RPM dependent sensors not yet checked:

CMP(Camshaft), CKP(Crankshaft),

I would check the relays 1st. In my experience, the sensors don't seen to experience intermittent failures.

 

[wjbertrand]

Thanks guys for the additional analysis. To some of the points mentioned and for addition food for thought. I did change out the fuel cut relay and I wiggled/tugged on the tip over and ignition switches. The area around the tip switch doesn't get very warm, even after racing the engine with the bike stationary. So I'm having trouble connecting that to the need for the bike to be fully warm before it starts misbehaving. I would expect whilst underway, that area would remain even cooler than in the garage. I think I will test the crank and cam sensors with my multimeter. Since there were no error codes and the wiring/connector looks fine I didn't explore these further. Can't express my appreciation for your continued thoughts on this.


-Jeff

 

[ST-Traveler]

As soon as this gets diagnosed I will be going to my ST to see if mine is OK. Been following this thread but I don't have any ideas as to the possible cause.

 

[wjbertrand]

I understand that the crankshaft position sensor on the ST1300 is essentially equivalent to what's call an igniter in the Honda car world. The Honda parts fiche describes it as a pulse generator. I went ahead and googled "faulty Honda igniter symptoms", leaving off the "ST1300" part, and found some interesting posts that described three of the four symptoms / factors I am having, i.e. a requirement for some heat, the engine misfiring, hesitation and cutting out, and interestingly enough, the tachometer dropping to zero! The only thing missing was the specific RPM bit. In some cases there were no associated error codes.

I was out of town this weekend so haven't had a chance to test mine, though I doubt I'll find it out of spec based on the set of specific circumstances required for the faults to appear, I've ordered a used replacement off of eBay for ~$14 that came off the same year ST1300 with only 18K on it. Should be here by the end of the week. wish me luck!

 

[Blrfl]

Good luck, Jeff!

Keith and I were talking about this yesterday while we were elbows deep in his engine, and beyond what I said in #84, I'm stumped.

--Mark

 

[Pete in PA]

Yeah, I'm stumped also. That specific RPM thing REALLY throws me off.

 

[ibike2havefun]

Good luck, Jeff!

Keith and I were talking about this yesterday while we were elbows deep in his engine, and beyond what I said in #84, I'm stumped.

--Mark

We agreed that you should drive either 75 or 85 and avoid that RPM band.

 

[wjbertrand]

We agreed that you should drive either 75 or 85 and avoid that RPM band.

85 no problem 75 big problem... That's about where the misfire appears.

 

[Mark]

You know... I don't think any California speed limit is over 75mph... just saying...

 

[dduelin]

When you sort this you should be eligible for some sort of Perseverance In Troubleshooting Award.

 

[wjbertrand]

Latest Update:

I so wanted to report that it was fixed today, but, alas, it's not. Measures I've taken since my last update are; replaced the crankshaft position sensor. Initially I thought this had fixed it because I could not get it to misfire in the garage. Out on the road with about 15 miles riding, I sensed a mild misfire, again still at the 4200 - 4250 RPM spot, but it was much less severe and more intermittent. Before that I tried disconnecting the O2 sensors, clearing the ECM with a battery disconnect and then running it that way. Of course this set a error code but the bike ran fine except it was still misfiring. I slapped the faring back on and rode her to work this morning and the very mild misfire was still there until I got 30 - 35 miles into my 46 mile commute where the misfire reared it's ugly, nasty, stinkin' head again and got really bad - like riding a bucking bronco anywhere around that sensitive RPM. It was cooler this morning so that may have delayed the issue. I also had a full tank of fuel and it seemed like the problem really appeared after a couple miles of lane splitting at low speed.

So changing the crank position sensor is the first attempted repair that seemed to make any difference in the bikes behavior at all. Ultimately it is obviously not the solution but maybe there's a clue there.

The only thing left to try is the fuel pump but I'm really confused why it would act up at a specific RPM, under light to no throttle, and affect the tachometer.

 

[adamk]

Latest Update:
I slapped the faring back on and rode her to work this morning and the very mild misfire was still there until I got 30 - 35 miles into my 46 mile commute where the misfire reared it's ugly, nasty, stinkin' head again and got really bad - like riding a bucking bronco anywhere around that sensitive RPM.

This sounds VERY familiar to what I experienced when I installed the Power Commander on my bike! I darn near got run over trying to pull out onto a 2 lane road when my bike did that exact same thing. When the Power Commander guys flew up to Seattle and put my bike on the dyno they were able to reproduce that same behavior. The bike looked like a bucking bronco on the dyno! I don't recall what the rpm range was when it started to happen. But, as soon as they pulled the PC from my bike the problem went away. They never were able to determine the cause. They gave me a refund and stopped selling the PC for the ST1300....

You tried an ECU swap with someone, right? If not, there will be a lot of donor bikes at WeSTOC!

 

[Art Franz]

I don't have any ideas at all on where to go with this, just want to try to help.

I only read the thread quickly but didn't see that you actually tried a different ECM. I've got one that runs the bike although I've never ridden it on the road. It's on a wrecked 06 that I still have intentions of getting back on the road again someday. You're free to borrow it if you like. Reply here and PM me the details.

Latest Update:

I so wanted to report that it was fixed today, but, alas, it's not. Measures I've taken since my last update are; replaced the crankshaft position sensor. Initially I thought this had fixed it because I could not get it to misfire in the garage. Out on the road with about 15 miles riding, I sensed a mild misfire, again still at the 4200 - 4250 RPM spot, but it was much less severe and more intermittent. Before that I tried disconnecting the O2 sensors, clearing the ECM with a battery disconnect and then running it that way. Of course this set a error code but the bike ran fine except it was still misfiring. I slapped the faring back on and rode her to work this morning and the very mild misfire was still there until I got 30 - 35 miles into my 46 mile commute where the misfire reared it's ugly, nasty, stinkin' head again and got really bad - like riding a bucking bronco anywhere around that sensitive RPM. It was cooler this morning so that may have delayed the issue. I also had a full tank of fuel and it seemed like the problem really appeared after a couple miles of lane splitting at low speed.

So changing the crank position sensor is the first attempted repair that seemed to make any difference in the bikes behavior at all. Ultimately it is obviously not the solution but maybe there's a clue there.

The only thing left to try is the fuel pump but I'm really confused why it would act up at a specific RPM, under light to no throttle, and affect the tachometer.

 

[wjbertrand]

I don't have any ideas at all on where to go with this, just want to try to help.

I only read the thread quickly but didn't see that you actually tried a different ECM. I've got one that runs the bike although I've never ridden it on the road. It's on a wrecked 06 that I still have intentions of getting back on the road again someday. You're free to borrow it if you like. Reply here and PM me the details.

Thanks Art, that's a really kind offer. I did try swapping ECMs with a different ST1300. The result was that his ST ran perfectly fine with my ECM installed and mine continued to misfire with his ECM installed in my bike. Based on that we've eliminated the ECM from suspicion.

 

[Pete in PA]

OK, the new CPS made a change. Maybe with a stronger signal it's overcoming a wire problem. Might be a chafed/burned/mouse eaten wire. Check the wires from the CPS back as far as you can.

 

[wjbertrand]

OK, the new CPS made a change. Maybe with a stronger signal it's overcoming a wire problem. Might be a chafed/burned/mouse eaten wire. Check the wires from the CPS back as far as you can.

Thanks, I did examine that. The lead from the crank sensor joins to and gets wrapped into a large harness bundle on the left side. No additional dedicated connectors between the one that plugs into the sensor itself and the main harness. I've inspected every mm of harness and wire I can access, short of peeling back the entire thing from stem to stern and cannot find any evidence of rodents, tears, cuts or anything else. Other than a bit of dust all the harnesses look perfect. If I saw some damage on the outside of the harness I'd dig in there but with no obvious signs or clues, I've no idea where to begin.

As I ride the bike more, I am becoming less and less convinced that the replacement crank sensor did anything, it seems to have resumed bucking and stumbling just as bad as before.

Turns out the company that sells those High Flow brand replacement fuel pumps on eBay and amazon is actually based here in Ventura. Stopped by on my way home from work last night and picked up a ST1300 specific kit for $65. I can't make sense of some of the symptoms, i.e. specific RPM and the tach behavior, with respect to a dodgy fuel pump but most of the bucking and missing posts here and on the other ST forums seem to have been solved replacing it.

One interesting observation last night. Whilst waiting for the traffic signal I revved the bike in neutral to the troublesome 4250 RPM and predictably it stumbled but when I closed the throttle again, the damn thing stalled. It took a bit of cranking (almost missed the signal) to get her to re-fire too. I have been having an occasional stalling issue with the bike for the past few months but it's been very sporatic, may 4 or 5 occurrences over the last few months. Pull up to a stop and *** - no engine.

 

[SupraSabre]

How about the fuel injectors?

 

[wjbertrand]

How about the fuel injectors?

I dunno? Checked the electrical stuff. Gotta think they're mostly ok. Would all 4 go bad at once? When she stumbles it feels like total power loss as opposed to a partial loss.


-Jeff

 

[SupraSabre]

Jeff,

Make a list of parts you have tested/swapped, and things you haven't tried.

I could probably put together parts for you to swap around and try (coils/spkplg wires, fuel injectors, main cpu, etc.)

Once you get that list, I'll take a look at my parts and send them to you. you can swap out and see if anything fixes your issues and we can go from there. I will need them back, but that would let you test things without having to buy them first.

My '04#1 is sitting waiting for a new waterpump and a whole lot of other work, so it won't be going anywhere soon. I figure maybe in the winter, I'll get back to it. In the meantime, maybe this will get you fixed up.