Ignition Problem?

No I have not replaced or otherwise messed with the knock sensors. I've thought about disconnecting them and running without, just to see what happens. Already tried disconnecting the O2 sensors and that didn't do anything except throw an FI error code.


-Jeff
 
I really think the knock sensors should be looked at or replaced. Some vehicles disconnecting them works others do not.
 
wjbertrand said:
Must be. Somewhere deep down in a harness somewhere a wire has broken with no outward sign to give me a clue where to look. It's like finding a needle in a haystack. I sad say, I'm getting close to done with this thing.
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Sad to say with the fact it was "totaled and rebuilt" A lot can happen in a bad wreck that is not found. With all the time you've spent looking for this problem it may be time to let it go.
 
Well the total was declared because of old age (8.5 years) and high mileage (135k) on the bike - it was all cosmetic damage. I've put 12-15K on it since that happened before this problem reared it's ugly head. The salvage title no doubt affects its value though.
 
I'm the kind of person that looks at these kinds of problems like a challenge. I can't stand it when I can't figure out the problem and love trying to figure them out. I could never give a bike away or sell it without figuring out what was wrong with it. I guess I'm a little OCD about these things. LOL
 
bdalameda said:
I'm the kind of person that looks at these kinds of problems like a challenge. I can't stand it when I can't figure out the problem and love trying to figure them out. I could never give a bike away or sell it without figuring out what was wrong with it. I guess I'm a little OCD about these things. LOL
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Yup, that's exactly my mind set.
 
Unplugging the knock sensors had no effect on the problem, other than causing the FI fault light to come on.


Interesting observation this morning: I have the CCS-100 Audiovox cruise control installed on my bike. If I engage it above 4250 RPM or below 4000 RPM it works fine. If manage to engage it in the troublesome range, it will kick off the minute the stumbling happens.


Before we blame the CC itself, know that I've run the bike with it completely disconnected and that had no effect on the problem, so I am looking at this as a diagnostic hint perhaps rather than a fault with the cruise control system. Does this point to ignition vs. a fuel problem?
 
The ignition system and fuel injection timing are controlled from the same trigger from the pulse coil and cam sensor. HMMM
 
Sure seems to be adding up to - some sort of problem with the IPG signal input at the ECM.
Would be nice to hook up an o-scope and have a look at some of the signals (especially the IPG input at the ECM). Would eliminate some of the guess-work.
If I lived closer... I'd bring my scope and my ST (to use as a base-line comparison).
Do you know anyone with a scope? I could grab some traces from my 03 running at 4250 RPM to compare with yours.
 
I've stayed out of this thread because I have nothing to offer... until now? I was describing this issue to the guy at the shop when I picked up my bike today, and he described a similar issue (on another brand of bike) that he "solved" by methodically disconnecting, cleaning, and re-connecting every.single.connection.he.could.get.to. He never found an obvious culprit or smoking gun, but the owner called a month later to report that the gremlin had indeed gone.

Is it possible that it is the cumulative effect of a bunch of marginal connections throughout the harness?
 
wjbertrand said:
Interesting observation this morning: I have the CCS-100 Audiovox cruise control installed on my bike. If I engage it above 4250 RPM or below 4000 RPM it works fine. If manage to engage it in the troublesome range, it will kick off the minute the stumbling happens.
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I don't know a whole lot about the Audiovox CCS-100. What little reading I've done, it seems that when integrating the CCS-100 into the ST's electrical system it can be done in a number of ways. Specifically as it relates to the "Tach" signal, it can be: A) connected to the primary of one of the coils, or B) connected to the ECM tach signal. Which method did you choose? And how/where, specifically, did you make the connection? Also, when you disconnected the CC in the past, did you completely disconnect the CC's "Tach" signal wire? Could you explain more about how you disconnected the CC?

EDIT: I guess, where I'm going with this is - did you solder & shrink wrap connections? Or did you just twist some wires together and then wrap em with electrical tape (don't laugh, I've seen that), or somewhere between? If you integrated with the ECM tach signal, and that integration point introduced any additional impedance, I can see that having a bearing on things.

EDIT2: Have you checked/inspected the connection in the attached photo? Is it clean, corrosion-free, and solidly connected? This 2-pin connector (with one yellow & one white/yellow) isn't depicted in the wiring diagrams, but is in-line between the IPG and the ECM. It's situated beneath the pillion seat, next to the right-side frame member.
 

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Ok a bit more detail on the cruise control. It's connected to the left side ignition coil at the + primary terminal. When I disconnected it I cut the wire clean through. I always twist tight, solder and shrink wrap any electrical connection. My dad was an electronics engineer and he taught me well. I don't think I had checked that particular connector, but I have methodically checked just about every other one I could reach. Thanks, I'll look at it next.

Update: I managed to separate that connector, mine was much more tightly wrapped to the harness than shown in the image above. Anyway, the wires and connector contact look unremarkable, no obvious problems. I pried the harness away from the frame to see if there were any abrasions to the larger harness or to the leads of this connector and again everything looked to be in good shape. I sprayed out both sides of the connector with my plastic safe contact cleaner and clipped the connector back together 2-3 times. Rode the Tenere today though, so I'll test this later.


-Jeff
 
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Ok, spent several hours on the dyno with "PJ" this morning. Looks like a fuel problem at the lower RPM. The dyno showed some rough running as low as 2500 RPM. I thought I could feel some "unsteadiness" there before, but couldn't be sure it wasn't the road. Pretty much eliminated any spark or overall system voltage problems. He's thinking the O2 sensors may be faulty and driving the a/f ratio too low.

When he turned off the fans in the dyno room to drive engine temperature up a bit (still showed 3 bars) the a/f ratio richened and the misfire stopped. Turned on the big fans again and after engine temps came back down a bit it went leaner and started missing again.

So when the engine is cold started, mixture is relatively rich to stoiciometric (12-14) and there's no misfire. It gets into normal operating temps, the a/f ratio leans out (15-17) and it misses. Then driving the temps slightly higher than normal, the a/f again richens and the misfire stops. Not sure why higher temps cause richening? Maybe it's a protective thing the EFI does to try an reduce temps?

He's got friend who designs EFI, systems he's going to consult. I'll wait for the results of that before buying any O2 sensors.


-Jeff
 
I told PJ about that but he didn't really comment. It's possible that the CC just kicks off whenever there's a sudden RPM change. For example, it cannot be engaged with the bike on the center stand and in gear. When it is first activated it causes a slight surge. On the road it works fine with some resistance against the surge, but on the stand it just kicks off.


-Jeff
 
wjbertrand said:
Ok, spent several hours on the dyno with "PJ" this morning.
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Yay! More data! :D

So when the engine is cold started, mixture is relatively rich to stoiciometric (12-14) and there's no misfire. It gets into normal operating temps, the a/f ratio leans out (15-17) and it misses. Then driving the temps slightly higher than normal, the a/f again richens and the misfire stops.
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The oxygen sensors don't work unless they're hot, so the ECM runs open-loop and rich until the engine reaches operating temperature. That leaves a bit of unburned fuel in the system that the PAIR valves can combine with fresh air, causing combustion and adding heat to the exhaust system. Disconnecting the sensors will do the same thing (run open-loop and vary the mixture with engine temperature). If the misfires go away under those conditions, it's a good bet that one or both of the sensors is feeding bogus information back to the ECM.

BTW, if you leave the PAIR system enabled while on the dyno, you may get a slightly distorted picture of how the engine is actually being fueled. PAIR just makes sure that fuel in the exhaust doesn't leave the bike.

None of this explains the dropouts as you fall through 4,250 RPM, but a good data point would be seeing if that goes away while the sensors are out of the picture.

Not sure why higher temps cause richening?
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Rich mixtures burn cooler than lean ones, so it might be a way to induce a small, well-controlled drop in temperature rather than taking the blunderbuss approach and turning on the radiator fans.

It's possible that the CC just kicks off whenever there's a sudden RPM change.
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The CCS-100 does that if you pull the clutch in and the engine revs up; it may do the same if it sees a sudden drop.

--Mark
 
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