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Discussion Starter #1
I'm getting an irritating misfire when I'm working the bike hard in the canyons and mountain roads.
Bike temp is averaging 180F, and it starts happening at about 3000 feet elevation.
I live at sea level, but I've been riding my bike in these same areas for years, this problem is new. Same PC3r and same fuel map-Kyle's Sato lowmount map.

Symptom:
Starts cutting out slightly at about 7000-7500. Continues cutting out till about 8000+.
Stops cutting out from 8000 and up, and seems fine below 7000, altho I feel slight occasional surging at a steady speed.

What I've done:
Replaced spark plugs, and air filters.
Honestly, I can't really 'feel' a difference, but they were due.
First pic is the old plugs, with about 7500 miles on them. Second pic is the new plugs with 250 miles on them. Do they look ok?
The fpr is new, but I checked it anyway, even put a little vacuum on the nipple - it held rock steady at 9Hg.

This is where I need help.
My line of reasoning is to check the following:
Bypass PC and ride the bike to see if that changes it.
While I have the tank raised, I'll check all the fuel injector connectors and pulse gen connector. I'll check coils, ECU, and CDI connectors.

Somehow I feel like it's not connectors.

Other facts about my bike:
2000 SP1 that's been well maintained for the last 10 years and 35,000 miles. It's at 51,000 now. Regular fluid changes, valve inspections, etc. My PC3r is at least 12 years old, but is secured snuggly in tail. Not bouncing around.

Suggestions and input appreciated. :smile2:
 

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Make sure the spark plug tips are tight, and the ends of the wires fully engage the plugs when seated in the bore. Swap out with a known good set of coils. I had a problem in my car where, high load, higher rpm would misfire. Spent quite a bit of $$$ on the fuel system, until I replaced the coils, and no more misfire.
 

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With such an issue I would normally suspect an ignition related problem and would begin by performing a Peak Voltage Test between the Ignition Pulse Generator and the ECM. I would perform this same test twice, both before and after disabling the PC3R, while noting any differences between the two test results. See Page 17-4 of the Service Manual for details. However, your comment about the problem beginning at an elevation of about 3,000 feet would lead me to the fuel system. Have you considered testing the BARO/MAP sensors? See Page 5-57 of the Service Manual for further details.

The BARO sensor is responsible for sensing changes in barometric pressure and alters the ECM behavior accordingly. It accomplishes this by varying its output voltage in response to altitude changes. It is possible that the sensor may fail at a specific point over its intended operating range, causing the ECM to incorrectly adjust the fuel settings at or above certain altitudes. Such a failure may cause the symptoms you are describing.

See the graph on Page 5-57 of the Service Manual to get an idea of how the sensors should behave when operating normally. Page 5-11 illustrates test points on the ECM to confirm output voltages.

BTW, the plugs look fine, though a bit on the rich side.
 
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Discussion Starter #5
Update.
I reset/zeroed the three buttons on the outside of the PC3r. Then I hooked my computer up to look at the fuel map.
It's been running the Kyle Sato lowmount map, and on the surface, everything looks as it should. I recalibrated the throttle position sensor too.

Then I took a serious ride Saturday morning. It ran very well thru the rpm ranges at all altitudes.
But later that afternoon, when the weather got hotter and hotter as I was coming down in elevation, the misfire started happening again. especially at low rpm. I could hardly keep it running below 4000rpm. Got on the freeway and at constant speed it pretty much smoothed out until I hit the city streets again. Had to keep cranking the throttle some to keep it from dying and it was surging from 1000 to 3000rpm when held at quarter throttle. Made it home.

I believe it's safe to say altitude isn't in the picture anymore, however, heat seems to be. All the times this has happened it has been hot weather and the bike's been working hard.

I'm going to ride once more with the PC3r unhooked and see what happens. After that, as per the advice above, I'll see if I can get a peak voltage adapter for my multimeter, and test the coils and pulse generator.
 

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Discussion Starter #6
Just got back from a test ride and it's not the PC3r. I'm still getting a terrible stumble when I try to start from a standing stop. Imagine trying to start in second gear with OEM sprockets. That's what it feels like and I have -1+2 sprockets. In first gear, I have to really feather the clutch to get going or it will stumble and die. And of course, then the notorious SP1 clutch judder starts up - complicating acceleration even more.

I realize the symptoms are kinda changing, a little erratic. I'm still leaning towards electrical.
Peak voltage test to come next.
Maybe I'll end up doing the coil over plug mod. Don't know yet, have to (keep trying to) figure the real source of the problem.

Special thanks to Wibbly and Enxss for their detailed advice.
 

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It could be a battery/charging system thing as well.

If you have a small multimeter you can install it on the bike and monitor voltages as the issue is occurring.
 

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Discussion Starter #8 (Edited)
It could be a battery/charging system thing as well.

If you have a small multimeter you can install it on the bike and monitor voltages as the issue is occurring.
This is good because the problem occurs most as load increases.

Been considering the charging system too. It's a little lower on the list of possibilities, simply because I continue to have ample cranking power and my battery is only about 6 months old.

I'll include a stator test and reg/rec check on my to do list. Rick's, (the ones that sell the mosfet reg/rec) offer a nice little voltmeter that I've been thinking about for sometime now.

But for the moment, I need to get a peak voltage adapter and see what the coils are putting out.
 

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Have you tried performing a Self-Diagnostic on the injection system since your last ride? See Page 5-7. If so, are you getting any error codes?
 

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Discussion Starter #10
Have you tried performing a Self-Diagnostic on the injection system since your last ride? See Page 5-7. If so, are you getting any error codes?
The FI light has acted normally, no codes. I haven't done the test yet. Done it a few times in the past, cleared all the codes last time I had an issue that got resolved.
 

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Discussion Starter #12 (Edited)
While I was waiting for the peak voltage adapter to arrive, I tested the reg/rec to eliminate it as a source of the problem. I had low 14's at idle, and mid 14's at 5000 rpm. Battery is at 13.1 V at cold rest.
I'm ruling out the charging system.
Peak Voltage adapter came last night, I'll be testing the coils, pulse generator, and if I can figure out how-the cdi box, this weekend.

I was able to start and warm the bike up for the reg/rec test. It will run normal under no load except for the random stumble.

Edit: You were right Wibbly, the plug caps unscrew from the wires, and the wires unscrew from the coil.
The wires showed .3 ohms. But I couldn't get a reading from the cap. Is the cap supposed to add a lot of resistance or am I not doing it right?
btw, this was done a a spare coil I had laying around, not the ones on my bike. Yet.
 

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There are four points where you can perform the Peak Voltage Test. One is at the harness connector where it plugs into the ECM. The second is at the two pin connector leading directly from the Ignition Pulse Generator. These first two points both measure the output of the Ignition Pulse Generator. Wire "Y". Page 7-0.

Points three and four measure the Peak Voltage being applied to the primary winding in each of the two ignition coils. Wires "Bu/Y" & "Y/Bu". In essence what you are measuring here is the output of the Converter Unit. The actual output of the ignition coils is many times greater than the 100 volts minimum output required from the Converter. The output of the secondary winding in each of the two ignition coils will need to be done by a visual inspection of the arc produced at the spark plug when it is connected to the plug wire and grounded.

The two points that you cannot test are the output of the ECM which triggers the Converter Unit; "Bl/Bu & Bl/Y". Is this what you are referring to when you question testing the CDI output?

As a suggestion, before performing any of the tests, trying starting the bike and letting it run in a dark area, e.g. at night, with the lower cowlings removed and visually inspect the ignition coils and plug wires for any high voltage leakage occurring from the secondary winding. The high voltage will 'flash' over the surface of the coils and/or plug wires if they are bad. You will only see this if it is very dark. Given your comment about heat being a possible factor, you may want to repeat the observation after bringing the bike to operating temperature if you do not see leakage when it is cold. This would be true for the Peak Voltage Tests as well.
 

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Discussion Starter #14
There are four points where you can perform the Peak Voltage Test. One is at the harness connector where it plugs into the ECM. The second is at the two pin connector leading directly from the Ignition Pulse Generator. These first two points both measure the output of the Ignition Pulse Generator. Wire "Y". Page 7-0.

Points three and four measure the Peak Voltage being applied to the primary winding in each of the two ignition coils. Wires "Bu/Y" & "Y/Bu". In essence what you are measuring here is the output of the Converter Unit. The actual output of the ignition coils is many times greater than the 100 volts minimum output required from the Converter. The output of the secondary winding in each of the two ignition coils will need to be done by a visual inspection of the arc produced at the spark plug when it is connected to the plug wire and grounded.


The two points that you cannot test are the output of the ECM which triggers the Converter Unit; "Bl/Bu & Bl/Y". Is this what you are referring to when you question testing the CDI output?

As a suggestion, before performing any of the tests, trying starting the bike and letting it run in a dark area, e.g. at night, with the lower cowlings removed and visually inspect the ignition coils and plug wires for any high voltage leakage occurring from the secondary winding. The high voltage will 'flash' over the surface of the coils and/or plug wires if they are bad. You will only see this if it is very dark. Given your comment about heat being a possible factor, you may want to repeat the observation after bringing the bike to operating temperature if you do not see leakage when it is cold. This would be true for the Peak Voltage Tests as well.
Update
I removed the left radiator last night to reveal an old solder-splice in the pulse gen wire. Need to unwrap it and see that it's sanitary, and dig deeper to finish visually inspecting all the connections and wires involved.Then I'll hook up my PC3r again, warm the bike up, turn out the lights and see what I can see.
I hadn't used a peak voltage tester before, so I did some initial tests to see how it works and make sure I was doing things right.
I didn't warm up the bike. All these numbers were on a cold engine. Since heat may be an issue for my problem, I may run these tests again with the bike all warmed up.

For testing, I followed the manual section 17. Started with the pulling the plugs - good spark.
At the coil connectors I got ~170V front and rear.
At the yellow wire-grey ECU connector I got about 15V. At the pulse gen connector I got about 15V. I was surprised to see a reading that much higher than the 0.7V minimum in the manual.
Is this ok?

I have an old coil. I unscrewed the wire from the coil, and the cap from the wire. With the cap in my hand, I saw a slot in the receptacle the plug snaps into. I unscrewed it and discovered behind it lies a resistor. It tested at 5.2K Ohms.

So I did the same to my bikes plug wires. They look very clean, resistors tested at 5.2K ohms, wires at .3 ohms. So I put 'em back together and started testing voltage.

Here's a picture of the spare coil.
 

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You've been busy. :smile2:

At the coil connectors I got ~170V front and rear.

Just to confirm, was the measurement taken under load? In other words, did you have the Primary Winding of the Ignition Coil in the circuit by using an adapter cable such as that illustrated on Page 17-5?


At the yellow wire-grey ECU connector I got about 15V. At the pulse gen connector I got about 15V. I was surprised to see a reading that much higher than the 0.7V minimum in the manual.

This does seem a bit high but it should be fine. In the case of the Ignition Pulse Generator (IPG), the Timing and the Duration of the pulse is more important than the actual peak voltage, assuming that the peak voltage is above the minimum 0.7V.

The function of the Ignition Control Module, which is an integral part of the ECM, is to process the input signal received from the IPG. It does this by taking the input from the IPG and dividing it into two channels; one for the front cylinder and one for the rear cylinder. It then adjusts the timing of the output for these two channels in response to engine speed. In the process, it normalizes the output voltage of the two channels to a Normally High logical output of 5.0 volts (Bl/Bu & Bl/Y). When an ignition pulse is required it toggles the output to a Logical Low of, ideally, 0.0 volts. This is what triggers the Converter Unit (CDI) to pulse the ignition coils. Incidentally, this is why you can not perform a Peak Voltage Test between the output of the ECM and the input of the Converter Unit (CDI).


... I saw a slot in the receptacle the plug snaps into. I unscrewed it and discovered behind it lies a resistor.

FYI. The resistor is there, in part, to act as a Noise Suppressor for the high voltage pulse produced by the secondary winding of the ignition coil.


Try running the bike in the dark as I suggested previously and see what you can see. It is possible that although the plug wires are metering as expected the insulation may be breaking down due to age and other factors, thus allowing high voltage to leak out sporadically. This is why I offered the suggestion.

BTW, do you know the Impedance of the Peak Voltage Tester that you are using?
 

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Discussion Starter #16
Just to confirm, was the measurement taken under load? In other words, did you have the Primary Winding of the Ignition Coil in the circuit by using an adapter cable such as that illustrated on Page 17-5?


BTW, do you know the Impedance of the Peak Voltage Tester that you are using?
I didn't have that tester they show in the manual. Hopefully, you can see what I came up with in the picture. Is that what you mean?

Testing the pulse gen voltage, I tapped into the pulse generator side of the connector.

It's an Electronic Specialties 640 DVA. I couldn't really find any specs on it.
 

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The setup shown in your images will work fine when testing the Ignition Pulse Generator (IPG). It is the testing of the Converter Unit (CDI) output that I was questioning.

Unlike the IPG, when testing the output of the Converter Unit (CDI) the voltage measurement must be taken under load. This means that the ignition coil must remain in the circuit. To accomplish this do not simply disconnect the two pin connector leading from the ignition coil to the bike's wire harness and then measure the voltage at the wire harness side of the connector. You need to connect a set of jumper wires between the two connector halves and then measure the voltage across the jumper wires. Attached is a quick sketch to help illustrate this.
 

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Discussion Starter #18
To accomplish this do not simply disconnect the two pin connector leading from the ignition coil to the bike's wire harness and then measure the voltage at the wire harness side of the connector.
?

Spark plugs were in the cylinders, and hooked up. All connectors were plugged in. Except the fuel pump.
Coils were completely connected. The +red and -green wires coming from the voltage tester, are tapped into the Bl/Y and Gr coil wires respectively.
The jumper wires I used have the ends stripped and soldered and filed down thin enough to slip into most connectors without unplugging them.

I thought this would accomplish the same thing as your sketch. No?
 

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While I was waiting for the peak voltage adapter to arrive, I tested the reg/rec to eliminate it as a source of the problem. I had low 14's at idle, and mid 14's at 5000 rpm. Battery is at 13.1 V at cold rest.
I'm ruling out the charging system.
OK, the Vdc values look good, but did you also test the altenator resistance and Vac output (over the yellow wires)?

The altenator gets "cooled" by engine oil and as things get hotter and hotter this may affect the unit. Espcially if it in a deteriorated state.
 
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