Intermittent Sputtering
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
Intermittent Sputtering
My '02 Road King, which has 83,000 miles on it, just developed a rapidly worsening intermittent sputtering condition. It usually happens during steady cruising, not speed dependent (It will do it at steady part throttle at almost any speed). It seems to me that I'm losing spark, though who really knows... Anyway, I'd like to test the coil, primary and secondary windings. Anyone have an electrical manual for '02 touring models? I just read through the service manual, which is not very helpful for troubleshooting. I will be testing the ignition wires (original) and having a look at the plugs, which aren't all that old, but might be ready for replacement.
I did stop at an Auto Zone and pick up a new set of NGK's. While checking for the plug number I discovered the screw-on terminal on the end of the plugs were loose, which I hoped would solve my problem, but did not. Plug wires appear in good condition but have not been tested for proper resistance yet.
No check engine light and seems to accelerate strongly, which is not really in line with my experience with faulty coils; most of the ones I've run across would idle just fine but not fire the plugs under load. OTOH, my old Ironhead fried its coil and acted similar to this before it finally gave up completely.
Suggestions welcome.
I did stop at an Auto Zone and pick up a new set of NGK's. While checking for the plug number I discovered the screw-on terminal on the end of the plugs were loose, which I hoped would solve my problem, but did not. Plug wires appear in good condition but have not been tested for proper resistance yet.
No check engine light and seems to accelerate strongly, which is not really in line with my experience with faulty coils; most of the ones I've run across would idle just fine but not fire the plugs under load. OTOH, my old Ironhead fried its coil and acted similar to this before it finally gave up completely.
Suggestions welcome.
Outstanding HDF Member
Joined: Oct 2010
Posts: 2,706
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From: Near Frankenmuth, MI
You might have to give a bit more detail than just "sputtering". At an idle, under load, going fast? A miss, a back fire, a pop out the pipes, or carb? Does it hesitate, not accelerate, or stall?
Have you repaired, or replaced, or updated anything lately?
It happens so much I find myself seemingly suggesting it over and over but do an intake leak test. Seals and gaskets on the intake go bad and are often an issue with bad running.
You could have a faltering ignition sensor. Not certain if it's on your model but the throttle sensor on some models becomes contaminated and has to be cleaned or replaced.
Let us know more precisely what is happening and when.
Have you repaired, or replaced, or updated anything lately?
It happens so much I find myself seemingly suggesting it over and over but do an intake leak test. Seals and gaskets on the intake go bad and are often an issue with bad running.
You could have a faltering ignition sensor. Not certain if it's on your model but the throttle sensor on some models becomes contaminated and has to be cleaned or replaced.
Let us know more precisely what is happening and when.
Thread Starter
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
I thought I was pretty specific, but maybe I wasn't clear. I believe the ignition is cutting out. I would like the resistance values of the primary and secondary windings of the coil, if anyone has them, so that I can test the coil.
The sputtering occurs at steady speeds and steady throttle position, does not occur under load or acceleration. "Sputtering" in this case is cutting out. As I said, it feels like the ignition is cutting out.
To that end, I have checked the battery connections, looking for a loose ground or some such, and found none. I have looked over the plug wires which appear ok, although they have 83,000 miles on them.
Again, there is no check engine light. That's about as specific as I can get. Anyone have those test values for the coil?
In addition, I am open to other suggestions.
The sputtering occurs at steady speeds and steady throttle position, does not occur under load or acceleration. "Sputtering" in this case is cutting out. As I said, it feels like the ignition is cutting out.
To that end, I have checked the battery connections, looking for a loose ground or some such, and found none. I have looked over the plug wires which appear ok, although they have 83,000 miles on them.
Again, there is no check engine light. That's about as specific as I can get. Anyone have those test values for the coil?
In addition, I am open to other suggestions.
Thread Starter
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
Just what did youvmean by "ignition sensor"? I know of no such sensor. I assume by "throttle sensor" you mean Throttle Position Sensor. What exactly gets dirty on a TPS, which is a potentiometer?
Road Captain
Joined: Mar 2008
Posts: 712
Likes: 55
From: Punta Gorda, Florida
The R values and acceptable ranges are 2.5-3.1 ohms and 10,000 - 12,500. ohms. Unfortunately, in some case the resistance will read correctly when it is cold, but falter when it gets hot. Check it cold, go for a ride till it start sputtering, then check again.
Thread Starter
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Tourer
Joined: Jul 2007
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From: New Egypt, NJ
Thanks, Harry. The good cold/faulty hot is part of what's making me suspect the coil. it runs smoothly cold & gets rough once it gets hot. PITA to check hot the way it's tucked up in there! By the time I get the tank loose it will probably be cooled off enough to go back to "good"!
Road Master
Joined: Apr 2009
Posts: 851
Likes: 1
From: Indiana
I had same symptoms on my bike and eventually found my base gaskets were weeping causing my plugs to carbon foul. Check for any air leaks & make sure battery is load tested. Electronically, I would start with pick up sensor, ignition module, and then coil.
Last edited by 95custmz; Nov 18, 2012 at 12:01 PM.
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Road Master
Joined: Apr 2009
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From: Indiana
There is a way to test coil in garage for temperature variations. Use freeze spray(which can be found at aotumotive store) and hair dryer to mimic hot and cold temps. while bike is at idle.
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Outstanding HDF Member
Joined: Oct 2010
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From: Near Frankenmuth, MI
I thought I was pretty specific, but maybe I wasn't clear. I believe the ignition is cutting out. I would like the resistance values of the primary and secondary windings of the coil, if anyone has them, so that I can test the coil.
The sputtering occurs at steady speeds and steady throttle position, does not occur under load or acceleration. "Sputtering" in this case is cutting out. As I said, it feels like the ignition is cutting out.
The sputtering occurs at steady speeds and steady throttle position, does not occur under load or acceleration. "Sputtering" in this case is cutting out. As I said, it feels like the ignition is cutting out.
Cutting off (out) completely tends to be a spark issue.
I'd check the timing sensor under the cone. These fail with temperature and are tested much the way you are thinking with the coils. You can run the bike at an idle and hit the sensor with cold, and then using a blow dryer warm it too to see if it gives you the issue your having.
Also at the point where the wiring comes out of the nosecone you can have broken or melted wires right there due to the sharp bend in the wiring, and the hot pipes being right there.
Sometime with an issue that pops up when a bike is real hot can be due to a wire that is in a bent position and vibrates itself in two. When cold the insulator keeps the wire contacting. Once warm the insulation expands just enough to stop the contact. They're hard to find. Easier if the bike is running when you tug and twist the wires to replicate the problem. You may even notice a narrowing and a fainter color on the over bent and stretched insulation spot.
Thread Starter
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Tourer
Joined: Jul 2007
Posts: 497
Likes: 8
From: New Egypt, NJ
Thanks for the clarification. I'll take a look at the TPS & see what it looks like. As for a sensor in the nose cone, I dunno if you're thinking Evo or what, but there's nothing in there in an '02 Twin Cam. Not in later ones, either, I don't think. At least there wasn't in the '11 I worked on.
I have no backfiring, just cutting out -- like you, I'm thinking spark -- hence the coil resistance test. Gonna start simple & replace pkugs first, then road test. test coil while cold as well, then while hot if it still cuts out. Maybe "cuts out" would have been a better description, but it doesn't stall or stop running completely - yet.
We'll see how it shakes out. I have a feeling I'm going to end up rolling the "diagnostic dice" and throwing a coil at it in the end but will test everything I can first.
Another thing making me think possibly a coil is that sometimes it doesn't jump right to life when it starts. Don't know how to explain other than a "soft start", which doesn't really make sense, I know, but it just doesn't seem to have a real strong spark at times.
I'll post results when I have some, maybe later this afternoon, gotta drop my wife at the airport here in an hour or so & might have time to look at it after that.
I have no backfiring, just cutting out -- like you, I'm thinking spark -- hence the coil resistance test. Gonna start simple & replace pkugs first, then road test. test coil while cold as well, then while hot if it still cuts out. Maybe "cuts out" would have been a better description, but it doesn't stall or stop running completely - yet.
We'll see how it shakes out. I have a feeling I'm going to end up rolling the "diagnostic dice" and throwing a coil at it in the end but will test everything I can first.
Another thing making me think possibly a coil is that sometimes it doesn't jump right to life when it starts. Don't know how to explain other than a "soft start", which doesn't really make sense, I know, but it just doesn't seem to have a real strong spark at times.
I'll post results when I have some, maybe later this afternoon, gotta drop my wife at the airport here in an hour or so & might have time to look at it after that.